SO: ORG.-GEOCHEM. 1993 vol. 20, no. 1, pp. 77-89
LA: English
AB: White and pigmented filamentous bacterial mats dominated by several undescribed species of Beggiatoa were sampled during research submersible dives to cold hydrocarbon seep sites on the upper continental slope off Louisiana (130-550 m). Mats occur at the interface between reducing sediments and the oxygenated water column. They are localized at sea floor features related to seepage of biogenic methane and crude oil, but there is little evidence that the organisms utilize the hydrocarbons directly. Granules of elemental sulfur (S super(0)) are visible within cells of Beggiatoa, and mat material is characterized by high contents of S super(0) (up to 193,940 ppm). The Beggiatoa biomass is isotopically light ( delta  super(13)C = -27.9ppt PDB). Our geochemical data suggest that the Beggiatoa species are part of a complex bacterial assemblage in cold seep sediments. They oxidize H sub(2)S derived from the bacterial sulfate reduction that accompanies bacterial hydrocarbon oxidation when O sub(2) is depleted in sediments, and fix isotopically light carbon from CO sub(2) that is the result of bacterial hydrocarbon oxidation. Beggiatoa mats appear to retard loss of hydrocarbons to the water column by physically retaining fluids in sediments, a function that could enhance production by other bacteria of the H sub(2)S and CO sub(2) needed by Beggiatoa.
AN: 3660462

                                                                    472 of 1521  
TI: Degradation of organic matter by several size fractions of plankton from the lower Dniester River and the Dniester Estuary
AU: Potapova,-N.A.
AF: Inst. Hydrobiol., Ukrainian Acad. Sci., Kiev, Ukraine
SO: HYDROBIOL.-J.;GIDROBIOL.-ZH. 1994;1993 vol. 30, no. 3, pp. 13-24;vol. 29, no. 2, pp. 12-22
LA: English
ER: B (Brackish); F (Freshwater)
AB: The picoplankton fraction (0.2-2.0  mu m) and the nannoplankton (2.0-4.0  mu m), consisting chiefly of bacteria, play the dominant role in the degradation of organic matter in the waters of the lower Dniester River and the Dniester estuary. The oxygen uptake by these organisms in the absence of larger planktonic organisms is comparable with that of whole water (which has not been filtered to separate the fractions) and exceeds that of whole water in about 25 percent of the cases.
AN: 3658493

                                                                    473 of 1521  
TI: Transfer of mercury between the atmosphere and lake or soil surfaces
AU: Xiao,-Z.F.; Munthe,-J.; Schroeder,-W.H.; Lindqvist,-O.
CA: Goeteborg Univ., (Sweden). Dep. of Inorganic Chemistry
SO: 1990 4 pp
NT: NTIS Order No.: N90-26419/3/GAR.
LA: English
ER: F (Freshwater)
AB: A flux chamber technique for the measurement of volatile mercury species is described. It is used to measure the direction and magnitude of the flux of mercury over lake and soil surfaces. Measurements carried out over four oligotrophic lakes with different mercury concentrations in their fish as well as different humic contents are described. The measuring apparatus is outlined and described. The measurements are concluded to be reasonably reliable. Significant diurnal and large seasonal variations in surface emission fluxes of vapor phase mercury are found in the waters from the four Swedish forest lakes. (DBO)
AN: 3657764

                                                                    474 of 1521  
TI: Calcification, photosynthesis, and global carbon cycles
AU: McConnaughey,-A.
AF: U.S. Geol. Survey, Box 25046, MS 413, Denver, CO 80225-0046, USA
CO: Past and Present Biomineralization Processes. Considerations about the Carbonate Cycle. IUCN-COE Workshop, Monaco (Monaco), 15-16 Nov 1993
SO: PAST-AND-PRESENT-BIOMINERALIZATION-PROCESSES.-CONSIDERATIONS-ABOUT-THE-CARBONATE-CYCLE.-IUCN-COE-WORKSHOP,-MONACO-MONACO,-15-16-NOVEMBER-1993. Doumenge,-F.;Allemand,-D.;Toulemont-A.-eds. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1994 no. Spec. Iss. 13 pp. 137-161
ST: BULL.-INST.-OCEANOGR.-MONACO no. Spec. Iss. 13
LA: English
ER: M (Marine)
AB: Photosynthetic carbon uptake from natural waters can induce calcification, but more commonly with aquatic plants and algae- invertebrate symbioses, calcification functionally precedes the photosynthetic utilization of bicarbonate. In this capacity, calcification generates protons, which are used to convert bicarbonate to carbon dioxide. Organisms which rely on this physiology tend to calcify in approximately 1:1 molar ratio to photosynthesis, in mildly alkaline, calcium rich waters such as the oceans. The use of calcification as a proton generator constitutes one of the most important adaptations to aquatic photosynthesis and probably accounts for most of the calcification which occurs globally. Because calcification counteracts the alkalinization and carbon dioxide depletion which accompanies photosynthesis, variations in the global rates of calcification influence aquatic and atmospheric carbon dioxide levels. Over phanerozoic timescales, calcification by photosynthetic organisms has played a major role in converting most of the carbon in the biosphere into limestone.
AN: 3656146

                                                                    475 of 1521  
TI: Symbiosis, calcification, and environmental interactions
AU: Buddemeier,-R.W.
AF: Kansas Geol. Surv., Univ. Kansas, Lawrence, KS 66047, USA
CO: Past and Present Biomineralization Processes. Considerations about the Carbonate Cycle. IUCN-COE Workshop, Monaco (Monaco), 15-16 Nov 1993
SO: PAST-AND-PRESENT-BIOMINERALIZATION-PROCESSES.-CONSIDERATIONS-ABOUT-THE-CARBONATE-CYCLE.-IUCN-COE-WORKSHOP,-MONACO-MONACO,-15-16-NOVEMBER-1993. Doumenge,-F.;Allemand,-D.;Toulemont-A.-eds. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1994 no. Spec. Iss. 13 pp. 119-135
ST: BULL.-INST.-OCEANOGR.-MONACO no. Spec. Iss. 13
LA: English
ER: M (Marine)
AB: Enhancement of calcification by algal symbiosis is important to our understanding of evolution and the geologic record, contemporary ecology and biogeochemical cycles, and the potential future effects of human alteration of the global carbon cycle. Recent trends in coral reef research have oversimplified the diversity of algal symbiosis and largely ignored the potential effects of inorganic chemical controls on calcification at all scales. This paper describes and justifies a revised conceptual framework for the investigation of biocalcification and its symbiotic enhancement, with particular emphasis on coral reef issues.
AN: 3656143

                                                                    476 of 1521  
TI: Phosphorus dynamics following restoration measures in the Loosdrecht Lakes (The Netherlands)
AU: Van-Liere,-L.; Gulati,-R.D.; Wortelboer,-F.G.; Lammens,-E.H.R.R.
AF: Limnol. Inst., Rijksstraatweg 6, 3631 AC, Netherlands
CO: Int. Symp. on Trophic Relationships in Inland Waters, Tihany (Hungary), 1-4 Sep 1987
SO: TROPHIC-RELATIONSHIPS-IN-INLAND-WATERS. Biro,-P.;Talling,-J.F.-eds. 1990 vol. 191 pp. 87-95
ST: HYDROBIOLOGIA vol. 191
LA: English
ER: F (Freshwater)
AB: External phosphorus loads to three shallow lakes in the Netherlands were reduced by eliminating waste-water discharge and by dephosphorization of the supply water, with which water level is controlled. Concentrations of total-phosphorus and chlorophyll a were significantly reduced during 1980-1986 in L. Breukeleveen, but not in L. Vuntus and L. Loosdrecht. In 1983-1986 the phosphorus flow through several trophic levels was determined. Changes over these years were not significant. External input to the lakes still contributes substantially to the phosphorus input. Release from the sediments also contributed to the cycling of the phosphorus. Excretion by large crustacean zooplankters was important in phosphorus recycling, and delivered 20-30% of the daily phytoplankton phosphorus demand. A similar contribution is expected from fish. If one wants recovery of the lakes to be accelerated, additional measures are needed. (DBO)
AN: 3655624

                                                                    477 of 1521  
TI: Exchange of phosphorus across the sediment-water interface
AU: Bostroem,-B.; Andersen,-J.M.; Fleischer,-S.; Jansson,-M.
AF: Dep. Limnol., Uppsala Univ., Box 557, S-751 22 Uppsala, Sweden
CO: Phosphorus in Freshwater Ecosystems, Uppsala (Sweden), 25-28 Sep 1985
SO: PHOSPHORUS-IN-FRESHWATER-ECOSYSTEMS. Persson,-G.;Jansson,-M.-eds. 1988 vol. 170 pp. 229-244
ST: HYDROBIOLOGIA vol. 170
LA: English
ER: F (Freshwater)
AB: In this article, principles of phosphorus retention and phosphorus release at the sediment-water interface in lakes are reviewed. New results and hypotheses are discussed in relation to older models of phosphorus exchange between sediments and water. The fractional composition of sedimentary phosphorus is discussed as a tool for interpretation of different retention mechanisms. Special emphasis is given to the impact of biological, particularly microbial, processes on phosphorus exchange across the sediment-water interface and to the significance of biologically induced CaCO sub(3) precipitation to phosphorus retention in calcareous lakes. (DBO)
AN: 3655607

                                                                    478 of 1521  
TI: The sulfur cycle of freshwater sediments: Role of thiosulfate
AU: Jorgensen,-B.B.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: LIMNOL.-OCEANOGR. 1990 vol. 35, no. 6, pp. 1329-1342
LA: English
ER: B (Brackish); F (Freshwater)
AB: The formation and pathways of thiosulfate (S sub(2)O sub(3) super(2-)) in anoxic sediment were studied in the Odder River and Brabrand Lake, Denmark. Time-course experiments were done in slurries with four  super(35)S tracers: SO sub(4) super(2-), H sub(2)S, and S sub(2)O sub(3) super(2-) with either the inner (oxidized) or the outer (reduced) S atom labeled. The two sediments gave similar results. Of all the S sub(2)O sub(3) super(2-) consumed in Brabrand Lake sediment, 6% was oxidized, 50% was reduced, and 44% was disproportionated. S sub(2)O sub(3) super(2-) disproportionation is an inorganic fermentation in certain SO sub(4) super(2-)-reducing bacteria by which the inner and outer S atoms are simultaneously transformed into SO sub(4) super(2-) and sulfide, respectively. Altogether, 28% of the S sub(2)O sub(3) super(2-)-S was converted into SO sub(4) super(2-) and 72% was converted into sulfide. S sub(2)O sub(3) super(2-) inhibited SO sub(4) super(2-) reduction by 75%. The immediate products of anoxic sulfide oxidation were 34% SO sub(4) super(2-) and 66% S sub(2)O sub(3) super(2-). Half of the oxidized sulfide was ultimately converted into SO sub(4) super(2-) and half was recycled back to sulfide via S sub(2)O sub(3) super(2-). Two-thirds of the S in the sulfide-thiosulfate "minicycle" remained at an oxidation state of -2. S sub(2)O sub(3) super(2-) is thus a key intermediate in the S cycle, both as a main product of anoxic sulfide oxidation and as a shunt between oxidative and reductive pathways.(DBO)
AN: 3655581

                                                                    479 of 1521  
TI: Ammonium recycling limits nitrate use in the oceanic subarctic Pacific
AU: Wheeler,-P.A.; Kokkinakis,-S.A.
AF: Coll. Oceanogr., Oregon State Univ., Corvallis, OR 97331-5503, USA
SO: LIMNOL.-OCEANOGR. 1990 vol. 35, no. 6, pp. 1267-1278
LA: English
ER: M (Marine)
AB: Seasonal and diel changes in nutrient concentrations and nitrogen assimilation rates were used to assess the effects of NH sub(4) super(+) on NO sub(3) super(-) assimilation. Surface-water NO sub(3) super(-) concentrations ranged from 6 to 17  mu M while NH sub(4) super(+) concentrations ranged from 0 to 0.4  mu M. Total N assimilation ranged from 84 to 732 nM/d but showed no seasonal trend. NH sub(4) super(+) and urea concentrations were <1% of total dissolved inorganic N, but use of this "regenerated" N still accounted for 44-89% of total N assimilation. Rates of NO sub(3) super(-) assimilation were negatively correlated with ambient NH sub(4) super(+) concentrations, and concentrations of NH sub(4) super(+) between 0.1 and 0.3  mu M caused complete inhibition of NO sub(3) super(-) assimilation. NO sub(3) super(-) was more important as a source of N in spring than in summer. We attribute this pattern to a summer increase in turnover rates for NH sub(4) super(+). Turnover times for the dissolved NH sub(4) super(+) pool were half as long in August as in May. Grazing and recycling in the euphotic zone apparently both play significant roles in preventing depletion of NO sub(3) super(-) in the oceanic subarctic Pacific. (DBO)
AN: 3655579

                                                                    480 of 1521  
TI: Implications of high dissolved organic matter concentrations for oceanic properties and processes
AU: Jackson,-G.A.
AF: Inst. Mar. Resour., Scripps Inst. Oceanogr., La Jolla, CA 92093, USA
SO: OCEANOGRAPHY 1988 vol. 1, no. 2, pp. 28-33
LA: English
ER: M (Marine)
AB: It has recently been argued that the dominant forms of reduced oceanic nitrogen and carbon may be overlooked by traditional techniques used to measure dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Suzuki et al. (1985) and Sugimura and Suzuki (1988) have reported that concentrations of DOC and DON in the ocean are 2 to 5 times those measured with previous techniques. Williams and Druffel (1988) have discussed the measurement issues and their implications for the nature of dissolved organic carbon in the sea. In this article, some of the implications of the new DOC and DON values for oceanic biology and chemistry are examined. (DBO)
AN: 3655148

                                                                    481 of 1521  
TI: The measurement of oceanic particle flux - Are "swimmers" a problem?
AU: Lee,-C.; Wakeham,-S.G.; Hedges,-J.I.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: OCEANOGRAPHY 1988 vol. 1, no. 2, pp. 34-36
LA: English
ER: M (Marine)
AB: About 10 years ago, the use of sediment traps to measure oceanic particle fluxes and composition began to proliferate. This technique has now become widespread. Research on particle composition and flux using sediment-trap and other large-particle sampling technologies has clearly shown the importance of particulate matter in global biogeochemical cycles. It has become a major goal within the oceanographic community to understand the processes controlling particle production, transport and destruction on both small and large scales. Particularly important to these studies is an accurate estimate of particle production and flux in surface waters. Initially, sediment traps were used to collect particles without careful regard to in-situ bacterial decay of material in the traps. As it became clear that organic material in particles could be significantly degraded during the two-week and longer periods over which traps were deployed, poisons and preservatives became more commonly used to prevent decomposition. Typical poisons currently used are HgCl sub(2) and NaN sub(3), while common preservatives are formalin and salt. We are currently investigating the effectiveness of these and other compounds in preventing decomposition and alteration of particulate organic compounds collected in sediment traps. However, with the use of poisons and preservatives, another potentially more significant bias is introduced to sediment trap collections. This is the collection of "swimmers": zooplankton and other marine animals that swim into the trap and die. Under some circumstances, particularly in shallow traps placed in coastal areas, much of the material collected can be swimmers. We observed this in trap samples collected in the California Current during the VERTEX V experiments. (VERTEX was a multidisciplinary study of VERtical Transport and EXchange of material in the upper ocean.) Even in deeper or less productive waters, swimmers can be present in trap samples. (DBO)
AN: 3655147

                                                                    482 of 1521  
TI: Methane oxidation activity in various soils and freshwater sediments: Occurrence, characteristics, vertical profiles, and distribution on grain size fractions
AU: Bender,-M.; Conrad,-R.
AF: Max-Planck-Inst. Terrestrische Mikrobiol., Marburg, FRG
SO: J.-GEOPHYS.-RES.-D-ATMOS. 1994 vol. 99, no. 8, pp. 16531-16540
LA: English
ER: F (Freshwater)
AB: CH sub(4) oxidation activities from various soils and freshwater sediments were measured at low ( less than or equal to 2 parts per million by volume (ppmv)) and high ( greater than or equal to 1000 ppmv) CH sub(4) mixing ratios. Most of the tested soils acted as sinks for atmospheric CH sub(4). A correlation between the CH sub(4) oxidation activity and the numbers of methanotrophs was only observed at high (1000 ppmv) CH sub(4) mixing ratios. This indicates that the counted methanotrophs were not the bacteria which are oxidizing atmospheric CH sub(4) ( less than or equal to 1.7 ppmv). The CH sub(4) oxidation was due to prokaryotic microorganisms active only under oxic conditions. The CH sub(4) oxidation activity decreased at O sub(2) mixing ratios below 1-3% and was rather insensitive for the variation of O sub(2) at mixing ratios >3%. Undisturbed, stratified soils, and freshwater sediments showed vertical profiles of CH sub(4) oxidation activities with a distinct maximum. Sediments showed an exact correspondence between the number of methanotrophs and the maximum of CH sub(4) oxidation both being localized at the surface sediment layer. The oxic soils showed maxima of CH sub(4) oxidation activities generally located in subsurface layers. The maxima of CH sub(4) oxidation activities were slightly shifted below the maxima of the numbers of methanotrophs indicating that the counted bacteria (incubation under 20% CH sub(4)) might not represent the active population which oxidizes atmospheric CH sub(4). Plowed, agricultural soils showed no distinct maxima, neither of the CH sub(4) oxidation activities nor of the numbers of methanotrophs. The grain size fractionation by centrifugation or wet sieving of slurries of two forest soils showed that the bulk (80-96%) of the CH sub(4) oxidizing activity was attached to the smaller mineral fractions (clay, silt, fine sand) of these soils. Within the mineral fractions, greater particles had higher specific activities of CH sub(4) oxidation than smaller particles.
AN: 3654389

                                                                    483 of 1521  
TI: Historical evolution of the Southwest Florida coastline and its effect on adjacent marine environments
AU: Frederick,-B.C.; Gelsanliter,-S.; Risi,-J.A.; Wanless,-H.R.
AF: Geol. and Geophys., Rosenstiel Sch. Mar. Atmos. Sci., 4600 Rickenbacker Causeway, Miami, FL 33149, USA
CO: Symp. on Florida Keys Regional Ecosystem, Miami, FL (USA), Nov 1992
SO: SYMPOSIUM-ON-FLORIDA-KEYS-REGIONAL-ECOSYSTEM.-NOVEMBER-1992. Prospero,-J.M.;Harwell,-C.C.-eds. 1994 vol. 54, no. 3 pp. 1074-1075
ST: BULL.-MAR.-SCI. vol. 54, no. 3
NT: Abstract only.
LA: English
ER: M (Marine)
AB: An examination of historical aerial photography (1928-present) reveals three significant types of change in the coastal/wetland environment on the southwest coast of Florida between Cape Sable and Chatham River: coastal erosion, erosion of shorelines and islands in larger interior bays, and landward expansion of mangrove communities. There are two types of coastal erosion. Progressive erosion from winter storms has affected significant portions of this west-facing coastline. Hurricane surges penetrating tidal creek complexes have created local patches of catastrophic erosion within the wetland environment. Coastlines and islands within larger interior bays are eroding, especially along the north and east shores. This erosion has resulted from both recurrent winter storm waves and episodic hurricane scour. Eroded sediment is largely organic and is oxidized, dissolved or transported out of the system. Shore erosion within bays has resulted in the expansion of tidal prisms and in the enlargement of channels connecting to the offshore marine environment. During the past 52 years of historical records, some mangrove community boundaries have remained relatively stable while others have dramatically expanded across adjacent transitional and freshwater marshes. As much as 86 meters of landward expansion is recognized. Mangrove community expansion occurs by both episodic, storm-generated seedling introduction and progressive expansion. Gently sloping coastlines provide a setting to record the temporary advance of infringing mangrove communities in this wetland coastal landscape. Erosion of these coastlines is providing a significant volume of dissolved and particulate organics and nutrients into adjacent mangrove, transitional, and freshwater wetlands and into the adjacent marine environments. Organics and nutrients discharged into coastal marine waters are pulsed southward by winter storms into Florida Bay and the Florida Keys. Future global warming, with increased rates of sea-level rise and increased frequency of hurricanes, should dramatically increase rates of erosion of this wetland coastline and increase the importance of this area as a source for organic and nutrient discharge.
AN: 3654097

                                                                    484 of 1521  
TI: The ocean's role in global change: Progress of major research programs
CA: National Research Counc., Washington, DC (USA). Ocean Studies Board
SO: WASHINGTON,-DC-USA NATIONAL-ACADEMY-PRESS 1994 85 pp
LA: English
ER: M (Marine)
AB: During the past decade, the debate about whether Earth's climate is changing has intensified. Global - or even regional - climate shifts will have far-reaching implications for world economics, energy utilization, national defense, and the health of terrestrial and marine ecosystems. Although the role of the ocean in global climate is not fully understood, there is general agreement that it is significant. Climate models predict that increases in greenhouse gases may lead to significant regional and possibly global climate changes. The scientific community has initiated large-scale research programs based on studies of the ocean and its relation to global climate and climate related processes. This report, which describes the research programs, is divided into two main sections: programs that study processes that occur over periods ranging from days to hundreds of years - the contemporary system; and those that seek to understand long-term variations ranging from thousands to millions of years - the geological perspective. Some programs have both long- and short-term elements. A third section discusses crosscutting data-collection issues important to all programs.
AN: 3654090

                                                                    485 of 1521  
TI: An apparent contradiction in the role of phosphorus in Cenozoic chemical mass balances for the World Ocean
AU: Delaney,-M.L.; Filippelli,-G.M.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 4, pp. 513-527
LA: English
ER: M (Marine)
AN: 3653863

                                                                    486 of 1521  
TI: Accumulation of Th, Pb, U, and Ra in marine phytoplankton and its geochemical significance
AU: Fisher,-N.S.; Teyssie,-J.-L.; Krishnaswami,-S.; Baskaran,-M.
AF: Oceanogr. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: LIMNOL.-OCEANOGR. 1987 vol. 32, no. 1, pp. 131-142
LA: English
ER: M (Marine)
AB: The bioaccumulation of U, Th, Ra, and Pb in four diverse nanoplanktonic algal species and a picoplanktonic blue-green alga was determined with radiotracers. Among the nanoplankton, differences of 1-2 orders of magnitude in volume/volume concentration factors (VCFs) were observed for a given nuclide, but larger differences were observed among the four nuclides, with VCF values of Th > Pb > Ra  greater than or less than       U. The picoplankton cells, with greater surface: volume ratios, had significantly higher VCF values. The mean VCF values in the nanoplankton of Th and Pb were 1.5 x 10 super(5) and 3.6 x 10 super(4) in the light and 2.8 x 10 super(5) and 7.3 x 10 super(4) in the dark. The VCFs of Th and Pb in the picoplankton were both about 2 x 10 super(6), irrespective of light. Retention half-times of  super(228)Th and  super(210)Pb in fecal pellets of Artemia salina, fed radiolabeled diatoms, were 20-50 d, but >120 d for  super(228)Th at 4 degree C. The results suggest that sinking plankton and their debris could account for most of the natural series radionuclides sedimenting out of oceanic surface waters. (DBO)
AN: 3652005

                                                                    487 of 1521  
TI: Hydrogen distributions in marine sediments
AU: Novelli,-P.C.; Scranton,-M.I.; Michener,-R.H.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794, USA
SO: LIMNOL.-OCEANOGR. 1987 vol. 32, no. 3, pp. 565-576
LA: English
ER: M (Marine)
AB: Hydrogen concentrations have been measured in sulfate-reducing sediments of a British Columbian fjord and in Skan Bay, Alaska, as well as in the hemipelagic sediments of the eastern north tropical Pacific off the Mexican coast. In the sediments of both the Mexican shelf and Canadian fjord, hydrogen levels were lowest near the surface, increased with depth and reached a maximum pore-water concentration of about 25-35 nM before sulfate was totally depleted. Deeper in the sediments, H sub(2) levels decreased again. In Skan Bay sediments, concentrations of pore-water hydrogen increased almost linearly with depth to a maximum level of 60 nM. Measured rates of hydrogen production in Skan Bay sediments varied little with depth (about 200 nM/d), and in Skan Bay the hydrogen pool had a turnover time of, at most, several hours. Model-predicted net rates of hydrogen production in Skan Bay are not significantly different than zero. These results are consistent with the hypothesis of interspecies hydrogen transfer between hydrogen-producing and -consuming bacterial populations, which predicts low ambient hydrogen concentrations and tight coupling between production and consumption. (DBO)
AN: 3651967

                                                                    488 of 1521  
TI: Dynamics of seston constituents in the Ariege and Garonne rivers (France)
AU: Chauvet,-E.; Fabre,-A.
AF: Cent. Ecol. des Ressour. Renouvelables, C.N.R.S., 29 rue Jeanne Marvig, 31055 Toulouse Cedex, France
SO: HYDROBIOLOGIA 1990 vol. 192, no. 2-3, pp. 183-190
LA: English
ER: F (Freshwater)
AB: Water contents of suspended matter, algal pigments, particulate organic carbon and particulate phosphorus were measured in the rivers Garonne (2 sites) and Ariege (1 site) throughout an annual cycle. The general trend of the parameters was similar at the three sites. Depending on the sites, the period of algal growth (chlorophyll a + phaeopigments > 25  mu g/l), lasted from two to six weeks in August-September. The algal peaks reached 50 to 90  mu g/l of total pigments. High contents of particulate organic carbon (> 2 mg/l) occurred at the end of summer (coinciding with algal growth), and during the November and May floods. In summer 50-75% of the suspended matter was organic, in spring this was 10 times less. The high linear correlation between particulate organic carbon and pigment contents (r = 0.87; P = 0.0001) suggested an algal origin of at least part of the particulate carbon. Algal carbon was minor in the annual fluxes of particulate carbon (25 to 39% depending on the sites), but relatively high in comparison with other rivers. The mean particulate phosphorus content calculated over the year was 24  mu g/l; it varied from 15  mu g/l during the high water period to 28  mu g/l during the low water period. Likewise the percentage of particulate phosphorus in the suspended matter varied from 0.17 to 0.40. A negative linear correlation existed between particulate phosphorus content and specific discharge (r = -0.46; P = 0.0001). The very marked seasonal trend of the parameters and the interactions led us to differentiate two modes of the rivers' functioning: a 'hydrologic' phase and a 'biological' phase. The hydrologic phase (high water) was dominated by the processes of erosion and transfer over the whole catchment area and the flood plain, while the biological phase was characterized by a high primary production in the river bed. (DBO)
AN: 3651589

                                                                    489 of 1521  
TI: Towards a joint global ocean flux study: Rationale, objectives, planning, implementation
AU: De-Baar,-H.J.W.; Van-Aken,-H.M.; Fransz,-H.G.; Ganssen,-G.M.; Gieskes,-W.W.C.
CA: Nederlands Inst. voor Onderzoek der Zee, Texel (Netherlands)
SO: 1988 59 pp
NT: NTIS Order No.: PB91-142901/GAR.
RN: NIOZ-1988-14 (NIOZ198814)
LA: English
ER: M (Marine)
AB: The oceanic inventories and fluxes of carbon are of major importance for the global C cycle in past, present and future. The global scale of the problem and the intricate interactions between physical, biological, and chemical forces warrant both an international and a truly multidisciplinary approach. Objective of the ICSU/SCOR/JGOFS program is 'To determine and understand on a global scale the time varying fluxes of carbon and associated biogenic elements in the ocean, and to evaluate the related exchanges with the atmosphere, the sea floor and continental boundaries'. Planning for 1989-1999 is focusing on (1) Process studies in selected areas; (2) Time Series observations to be continued or newly started; (3) Global Survey largely through satellite observation. The merits of selected study areas in regions as the Antarctic Ocean, the Pacific Basin, the Northwest Indian Ocean and the North Atlantic Ocean are being exploited. Implementation is now well underway with the North Atlantic Pilot Study where ships from six countries participate in a study of the temporal and spatial shifts of C fluxes related to the spring and autumn plankton blooms. (DBO)
AN: 3651499

                                                                    490 of 1521  
TI: Are wetlands the key to the ice-age cycle enigma?
AU: Franzen,-L.G.
AF: Dep. Phys. Geogr., Goeteborg Univ., Reutersgatan 2C, S-413 20 Gothenburg, Sweden
SO: AMBIO 1994 vol. 23, no. 4-5, pp. 300-308
LA: English
ER: F (Freshwater)
AB: The Vostok record of carbon dioxide (CO sub(2)) and methane (CH sub(4)) indicates that these greenhouse gases play a decisive role in the glacial/interglacial interplay during the Quaternary. A new theory presented here suggests that the ice-age cycles are generated by the peat growth in temperate wetlands. Glaciations on the other hand are believed to be responsible for the successive transformation of landscapes into types suitable for wetland initiation. In this respect, comparisons between the global distribution of wetlands with areas subjected to glaciation during ice ages shown a remarkable correspondence. If the theory presented here is correct, with the rapidly increasing concentrations of, e.g. CO sub(2) from anthropogenic sources, we are only at the beginning of an incomparable interglacial epoch.
AN: 3651429

                                                                    491 of 1521  
TI: Comparison of the kinetics of ferrous iron oxidation by three different strains of Thiobacillus ferrooxidans
AU: Chavarie,-C.; Karamanev,-D.; Godard,-F.; Garnier,-A.; Andre,-G.
AF: Dep. Genie Chim., Ec. Polytech. Montreal, P.O. Box 6079, Succ. A, Montreal, PQ H3C 3A7, Canada
SO: GEOMICROBIOL.-J. 1993 vol. 11, no. 1, pp. 57-63
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Three different strains of Thiobacillus ferrooxidans were grown in aqueous ferrous sulfate solutions at 30.5 degree C and at pH 2.0 in a bioreactor. Their specific growth rate followed Monod kinetics. Their maximum specific growth rate ( mu  sub(m)) was between 0.138 and 0.148/h and their saturation constant (K sub(s)) was in the range from 0.338 to 0.479 g Fe super(2+)/L. Comparing our data with other data from the literature, we concluded that the kinetics of ferrous iron oxidation is independent of the strain used. A good approximation of the growth kinetics on ferrous iron of Thiobacillus ferrooxidans between 20 and 32 degree C and pH 2.0-2.5 is obtained by using  mu  sub(m) = 0.14/h K sub(s) = 0.4 g Fe super(2+)/L.
AN: 3651367

                                                                    492 of 1521  
TI: Significance of sedimentation for the termination of Phaeocystis blooms
AU: Wassmann,-P.
AF: Norwegian Coll. Fish. Sci., Univ. Tromso, N-9037 Tromso, Norway
CO: Workshop on the Ecology of Phaeocystis-dominated Ecosystems, Brussels (Belgium), Jan 1991
SO: J.-MAR.-SYST. 1994 vol. 5, no. 1, pp. 81-100
LA: English
ER: M (Marine)
AB: The role of sedimentation for the termination of Phaeocystis blooms is exemplified through case studies from the literature as well as from anecdotal evidence. Scenarios of high and low sedimentation following Phaeocystis blooms exist. Mass sedimentation was found in the Barents Sea and the Ross Sea, but vertical flux below the euphotic zone was insignificant in a north Norwegian fjord and the Weddell Sea. In general, no regular and recurring pattern of sedimentation events can be expected during Phaeocystis blooms. Factors influencing the fate of senescent Phaeocystis blooms are probably water depth, turbulent energy supply, aggregate formation, release of flagellated cells from colonies, microbial degradation, zooplankton grazing as well as lysis of colonies and cells. The role sedimentation plays for the termination of Phaeocystis blooms seems to be determined by the physical and biological characteristics of the specific ecosystem where the bloom occurs. In general, Phaeocystis-dominated ecosystems tend to endorse pelagic rather than benthic mineralization.
AN: 3650770

                                                                    493 of 1521  
TI: Microbial populations of hydrothermal fluid and plumes in the North Fiji Basin with reference to chemosynthesis
AU: Naganuma,-T.; Seki,-H.
AF: Deep Sea Res. Dep., Japan Mar. Sci. and Technol. Cent. (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237, Japan
SO: MAR.-GEOL. 1994 vol. 116, no. 1-2, pp. 243-253
NT: Special issue: North Fiji Basin: STARMER French-Japanese Program.
LA: English
ER: M (Marine)
AB: Bacterioplankton abundance of the hydrothermal plumes in the North Fiji Basin (NFB) was anomalously high in bottom waters at several sampling stations. Good correlation between the manganese concentration and the bacterial viable counts was found for the bottommost waters. Sulfur bacterial strains, supposedly major chemosynthetic microorganisms associated with hydrothermal activity, were isolated from the bottommost water. The bacterial population growth and the CO sub(2)-uptake by the sulfur bacterial strains suggested the sulfur bacteria in the plumes were facultatively autotrophic. Also, a sulfur bacterial strain from the hydrothermal fluid was shown to be thermophilic-eurybaric. Biogeochemical roles of the planktonic sulfur bacteria in the hydrothermal area were pointed out as: (1) a food source to filter-feeders of the vent fauna; and (2) a possible first settler of the hydrothermal ecosystems.
AN: 3650709

                                                                    494 of 1521  
TI: Trace element distributions in some saline lakes of the Vestfold Hills, Antarctica
AU: Masuda,-N.; Nakaya,-S.; Burton,-H.R.; Torii,-T.
AF: Dep. Chem., Fac. Fish. Sci., Hokkaido Univ., Hakodate-city, Japan 041
SO: BIOLOGY-OF-THE-VESTFOLD-HILLS,-ANTARCTICA. Ferris,-J.M.;Burton,-H.R.;Johnstone,-G.W.-eds.;Bayly,-I.A.E.-eds. 1988 vol. 165 pp. 103-114
ST: HYDROBIOLOGIA vol. 165
LA: English
ER: M (Marine)
AB: The distributions of trace elements in Shield, Ace and Burton Lakes of the Vestfold Hills were investigated. Three aspects are discussed as follows: (1) the vertical distribution of 18 trace elements in the three lakes, (2) the behaviour of trace elements in the lakes, especially that of manganese in Shield Lake, and (3) the origin of trace elements in antarctic saline lakes. High concentrations of trace elements were found in these coastal saline lakes, when compared to open ocean water. We suggest that the peak of total extractable manganese, found at 20 m in Shield Lake, was related to the oxic/anoxic water interface brought about by microbiological activity. Solid phase manganese at the upper oxic layer may have precipitated and then reached the anoxic boundary to be there reduced to manganese ion. This dissolved manganese may then have diffused upwards to be reoxidized to a solid form. This cycle, repeated many times, may have produced the Mn profile. The alkali, alkaline earth elements and Cl were probably derived from relict seawater. Other elements were present in similar concentration ratios to those of South Polar aerosols. Residence time calculations indicate that fallout of aerosol particles, themselves derived from various sources, is capable of accounting for the measured concentrations of some trace elements in Shield Lake. This source of trace elements may be significant for other antarctic saline lakes. (DBO)
AN: 3648417

                                                                    495 of 1521  
TI: Iodine distribution in an antarctic meromictic saline lake
AU: Butler,-E.C.V.; Burton,-H.R.; Smith,-J.D.
AF: CSIRO Mar. Lab., Div. Oceanogr., GPO Box 1538, Hobart, Tas. 7001, Australia
SO: BIOLOGY-OF-THE-VESTFOLD-HILLS,-ANTARCTICA. Ferris,-J.M.;Burton,-H.R.;Johnstone,-G.W.-eds.;Bayly,-I.A.E.-eds. 1988 vol. 165 pp. 97-101
ST: HYDROBIOLOGIA vol. 165
LA: English
ER: B (Brackish)
AB: Water samples collected from a range of depths in Ace Lake in the Vestfold Hills, Antarctica were analysed for iodine species by a polarographic method. Contrary to thermodynamic prediction, iodide was the predominant species in oxic surface waters. Total dissolved iodine was closely correlated with bacterial density down the water column. This observation and other data are used to postulate a scheme for the biological mediation of iodine distribution in the lake. (DBO)
AN: 3648416

                                                                    496 of 1521  
TI: Mangrove forests and faecal rain
AU: Chow,-B.A.; Bacon,-P.R.
AF: Univ. West Indies, Mona, Jamaica
SO: CARIBB.-MAR.-STUD. 1992 vol. 3, pp. 57-58
LA: English
ER: M (Marine)
AB: The findings are presented of studies conducted in Oyster Bay, an estuarine lagoonal site on the north coast of Jamaica with fringe Rhizophora to determine the importance of Aratus pisonii frass (the animal component of litter-fall) in the energy flow pathway in the mangrove forest ecosystem. The rhythmic daily feeding migration of A. pisonii up into the canopy results in the presence of Aratus faecal pellets in the Rhizophora litter production. Faecal pellets and other small frass components immediately into the detrital pool, in contrast to plant litter which undergoes a lengthy fragmentation and mineralization process.
AN: 3648316

                                                                    497 of 1521  
TI: Export of biogenic carbon to fish and to the deep ocean: The role of large plankton microphages
AU: Fortier,-L.; Le-Fevre,-J.; Legendre,-L.
AF: Dep. Biol., Univ. Laval, Ste-Foy, PQ G1K 7P4, Canada
SO: J.-PLANKTON-RES. 1994 vol. 16, no. 7, pp. 809-839
LA: English
ER: M (Marine)
AB: The turnover time of biogenic carbon in the ocean can be defined as the time elapsed between the photosynthetic uptake of dissolved inorganic carbon and the return of this carbon as CO sub(2) in surface waters of the atmosphere. Three compartments can be defined: short-lived carbon (< 10 super(-2) year), long-lived carbon (10 super(-2)-10 super(2) years) and carbon sequestered in deep water or sediments. Pelagic organisms that package small particles into larger ones lengthen the turnover time of biogenic carbon and, in some cases, transfer the carbon from a given compartment to a longer-lived one. The lengthening of turnover time should be a direct function of the ratio between the size of organisms and that of their food particles. Under some circumstances, large species of euphausiids and copepods, in the North Pacific and the Southern Ocean, contribute to the lengthening of carbon turnover time. However, the most efficient re-packagers of small particles into larger ones are salps, appendicularians, doliolids and thecosome pteropods, which feed on particles at least 3.5 orders of magnitude smaller than their own size. It is hypothesized that the capacity of these large microphages to swim explosively allows them to control phytoplankton blooms and prevent the development of particle concentrations that could clog their filtering apparatus. Salps, appendicularians and, to some degree, thecosome pteropods are frequent in the diet of some larval and adult fish, and thus contribute to some extent to the direct transformation of short-lived microbial carbon into longer-lived harvestable resources. Yet, the main ecological role of large non-crustacean microphages may reside in the production of fast-sinking, resistant, faecal pellets (in particular those of oceanic salps) that often make up the bulk of the vertical flux of organic material into deep waters, where biogenic carbon can be sequestered for long periods.
AN: 3648242

                                                                    498 of 1521  
TI: Benthic phosphorus regeneration, net primary production, and ocean anoxia: A model of the coupled marine biogeochemical cycles of carbon and phosphorus
AU: Van-Cappellen,-P.; Ingall,-E.D.
AF: Sch. Earth Atmos. Sci., Georgia Inst. Technol., Atlanta, GA, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 5, pp. 677-692
LA: English
ER: M (Marine)
AB: We examine the relationships between ocean ventilation, primary production, water column anoxia, and benthic regeneration of phosphorus using a mass balance model of the coupled marine biogeochemical cycles of carbon (C) and phosphorus (P). The elemental cycles are coupled via the Redfield C/P ratio of marine phytoplankton and the C/P ratio of organic matter preserved in marine sediments. The model assumes that on geologic timescales, net primary production in the oceans is limited by the upwelling of dissolved phosphorus to the photic zone. The model incorporates the dependence on bottom water oxygenation of the regeneration of nutrient phosphorus from particulate matter deposited at the water-sediment interface. Evidence from marine and lacustrine settings, modern and ancient, demonstrates that sedimentary burial of phosphorus associated with organic matter and ferric oxyhydroxides decreases when bottom water anoxia-dysoxia expands. Steady state simulations show that a reduction in the rate of thermohaline circulation, or a decrease of the oxygen content of downwelling water masses, intensifies water column anoxia-dysoxia and at the same time increases surface water productivity. The first effect reflects the declining supply of oxygen to the deeper parts of the ocean. The second effect is caused by the enhanced benthic regeneration of phosphorus from organic matter and ferric oxyhydroxides. Sedimentary burial of organic carbon and authigenic calcium phosphate mineral (francolite), on the other hand, is promoted by reduced ocean ventilation. According to the model, global-scale anoxia-dysoxia leads to a more efficient recycling of reactive phosphorus within the ocean system. Consequently, higher rates of primary production and organic carbon burial can be achieved, even when the continental supply of reactive phosphorus to the oceans remains unchanged.
AN: 3646144

                                                                    499 of 1521  
TI: Microcommunities and microgradients: Linking nutrient regeneration, microbial mutualism, and high sustained aquatic primary production
AU: Wetzel,-R.G.
AF: Dep. Biol. Sci., Univ. Alabama, Tuscaloosa, AL 35487-0344, USA
SO: NETH.-J.-AQUAT.-ECOL. 1993 vol. 27, no. 1, pp. 3-9
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Nutrient regeneration is essential to sustained primary production in the aquatic environment because of coupled physical and metabolic gradients. The commonly evaluated ecosystem perspective of nutrient regeneration, as is illustrated among planktonic paradigms of lake ecosystems, functions only at macro-temporal and spatial scales. Most inland waters are small and shallow. Consequently, most organic matter of these waters is derived from photosynthesis of emergent, floating-leaved, and submersed higher plants and microflora associated with living substrata and detritus, including sediments, as well as terrestrial sources. The dominant primary productivity of inland aquatic ecosystems is not planktonic, but rather is associated with surfaces. The high sustained rates of primary production among sessile communities are possible because of the intensive internal recycling of nutrients, including carbon. Steep gradients exist within these attached microbial communities that (a) require rapid, intensive recycling of carbon, phosphorus, nitrogen, and other nutrients between producers, particulate and dissolved detritus, and bacteria and protists; (b) augment internal community recycling and losses with small external inputs of carbon and nutrients from the overlying water or from the supporting substrata; and (c) encourage maximal conservation of nutrients. Examples of microenvironmental recycling of carbon, phosphorus, and oxygen among epiphytic, epipelic, and epilithic communities are explained. Recalcitrant dissolved organic compounds from decomposition can serve both as carbon and energy substrates as well as be selectively inhibitory to microbial metabolism and nutrient recycling. Rapid recycling of nutrient and organic carbon within micro-environments operates at all levels, planktonic as well as attached, and is mandatory for high sustained productivity.
AN: 3646141

                                                                    500 of 1521  
TI: Release rates of trace elements and protein from decomposing planktonic debris. 1. Phytoplankton debris
AU: Lee,-B.-G.; Fisher,-N.S.*
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: J.-MAR.-RES. 1993 vol. 51, no. 2, pp. 391-421
LA: English
ER: M (Marine)
AB: The release rates of Ag, Am, Cd, Ce, Co, Pb, Se and Zn from decomposing diatom cells were determined using gamma-emitting radiotracers; rates were compared with C and protein loss rates over time. Additionally, experiments were designed to evaluate various artifacts involved in the experimental use of radioisotopes, handling of biogenic debris, and the use of poisons. The release rates of C at 18 degree C exponentially decreased with time from 17.5% d super(-1) at 1 d to 2.7% d super(-1) at 6 d; those of protein slowed from 9.2% d super(-1) at 1 d to 2.0% d super(-1) at 6 d. Rates at 18 degree C were 2-4 times faster than rates at 4 degree C. Rate changes at both temperatures were much less pronounced from 6-25 d. Retention half-times (t sub(r1/2)s) of Ag, Am, Ce, Co and Pb in diatom debris were significantly greater than those of Cd, Se and Zn under the same conditions; t sub(r1/2) values decreased inversely with temperature. The t sub(r1/2) values of C and protein were generally comparable to those of Cd, Se and Zn, whereas the ratios of the other metals to C and protein increased significantly over time. Microbial activity very strongly enhanced Co scavenging onto decaying particles in the dark. The elemental loss rate data suggest that Cd, Se and Zn should generally follow the fate of organic C and protein in decomposing planktonic debris. These elements should be biologically recycled and have longer residence times in surface waters than the other metals which are more particle-reactive and which do not follow organic C and protein release.
AN: 3645577

                                                                    501 of 1521  
TI: The ecological significance of bacterial reduction of sulfate in bottom sediments of the Dnieper-Bug lagoon
AU: Samoylenko,-V.N.; Golovko,-T.V.
AF: Inst. Hydrobiol., Ukrainian Acad. Sci., Kiev, Ukraine
SO: HYDROBIOL.-J.;GIDROBIOL.-ZH. 1994;1993 vol. 30, no. 5, pp. 105-110;vol. 29, pp. 85-94
LA: English
ER: B (Brackish)
AB: The development of anaerobic zones and the bacterial reduction of sulfate ion in the Dnieper-Bug Lagoon were studied. The basic precondition for sulfate reduction is the presence of readily decomposable organic matter. When the rate of sulfate reduction exceeds 100 mg S super(2-)/m super(2)-day, both sulfate dissolved in the water and sulfate in the interstitial water of the sediments becomes involved in the process. The development of anaerobic zones causes a sharp deterioration of oxygen conditions and slows the decomposition of organic matter to one-half to one-fourth the original rate.
AN: 3645474

                                                                    502 of 1521  
TI: The possible involvement of methylcobalamin in the production of methyl iodide in the marine environment
AU: Manley,-S.L.
AF: Dep. Biol. Sci., California State Univ., 1250 Bellflower Blvd., Long Beach, CA 90840, USA
SO: MAR.-CHEM. 1994 vol. 46, no. 4, pp. 361-369
LA: English
ER: M (Marine)
AB: Methyl iodide (CH sub(3)I) is a biogenic iodocarbon of marine and estuarine waters, and is an important component in the biogeochemical cycling of iodine. A possible significant abiotic marine source of CH sub(3)I is the reaction of methylcobalamin (CH sub(3)-B sub(12)) with either iodide or molecular iodine (I sub(2)) in seawater. These reactions were shown to occur in seawater and buffered water. The reaction between iodide and CH sub(3)-B sub(12) was apparently second order. The pH had a slight but significant effect on the reaction rate at pH between 7 and 8, and a more pronounced effect at a pH < 7. Chloride, bromide, iodate and bicarbonate had no significant effects on CH sub(3)I production at the standard reaction pH of 8.5. Iodate in the reaction mixture did not affect the reaction rate at pH > 7.5, however, at pH < 7.5 the presence of iodate increased the rate of CH sub(3)I production (9 fold at pH 5) due to the probable formation of I sub(2). The addition of aquocobalamin to the reaction mixture (CH sub(3)-B sub(12) + iodide) enhanced CH sub(3)I production (63% at pH 5; 38% at pH 8.5) presumably by catalyzing the oxidation of iodide to I sub(2). Molecular iodine also reacted with CH sub(3)-B sub(12) to form CH sub(3)I. The separate addition of CH sub(3)-B sub(12), I super(-) or I sub(2) to coastal seawater, for a final concentration of 0.22 mM, 4.8 mM and 25 mu M, respectively, resulted in the detectable formation of CH sub(3)I. The significance of these reactions to the formation CH sub(3)I in the oceans is discussed.
AN: 3644929

                                                                    503 of 1521  
TI: Formation of volatile sulfides in freshwater environments
AU: Caron,-F.; Kramer,-J.R.
AF: Waste Manage. Syst., At. Energy Canada Ltd., Chalk River Lab., Chalk River, ON K0J IJ0, Canada
SO: SCI.-TOTAL-ENVIRON. 1994 vol. 153, no. 3, pp. 177-194
LA: English
ER: F (Freshwater)
AB: Organic Volatile Sulfides (OVS) of biogenic origin are ubiquitous in the environment and are an important contributor to the global atmospheric sulfur cycle. We show that OVSs are widespread in the freshwater environment. The species H sub(2)S, COS, CS sub(2), methanethiol (MeSH), dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) have been found in samples of freshwater and in freshwater algal cultures. A few C sub(2)-C sub(4) alkylated sulfur species were found, of which only 1-propanethiol was identified, but they were detected in less than 10% of the samples or cultures. No sulfide species predominates in freshwaters, unlike the case of DMS in marine waters. Freshwater algal cultures were grown under laboratory conditions using various sulfur sources and methyl donors. Sulfate concentrations did not influence the production of OVS, but L-methionine was key in the production of methylated sulfides. The other sulfur-containing amino acids (cysteine, cystine) did not influence the production of OVS. Methyl donors did not significantly affect OVS production, except for CH sub(3)I, which induced higher levels of methylated sulfides with Oscillatoria sp. We did not find any factor that affected the production of H sub(2)S, COS and CS sub(2).
AN: 3643963

                                                                    504 of 1521  
TI: Late Quaternary CaCO sub(3) production and preservation in the Southern Ocean: Implications for oceanic and atmospheric carbon cycling
AU: Howard,-W.R.; Prell,-W.L.
AF: Education Assoc., Woods Hole, MA, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 3, pp. 453-482
LA: English
ER: M (Marine)
AN: 3641601

                                                                    505 of 1521  
TI: The formation of apatite from crab faecal pellets
AU: Simkiss,-K.; Taylor,-M.G.
AF: Dep. Pure and Appl. Zool., Univ. Reading, Reading, RG6 2AJ, UK
SO: J.-MAR.-BIOL.-ASSOC.-U.K. 1994 vol. 74, no. 2, pp. 459-462
LA: English
ER: M (Marine)
AB: Intracellular granules have been isolated from the digestive gland of the shore crab Carcinus maenas (L.). These granules are normally shed from this tissue during the digestive cycle and are shown to occur in considerable numbers in the faecal strands. The granules are amorphous to x-ray diffraction and remain in this state in sea-water for several weeks, although they will transform into crystalline apatite in simpler saline solutions. The fate of these deposits in the marine environment is discussed in relation to their contribution to sediments and phosphorites.
AN: 3638874

                                                                    506 of 1521  
TI: Recent calcium carbonate dissolution in the Barents Sea: Paleoceanographic applications
AU: Steinsund,-P.I.; Hald,-M.
AF: Dep. Geol., IBG, Univ. Tromsoe, N-9037 Tromsoe, Norway
SO: MAR.-GEOL. 1994 vol. 117, no. 1-4, pp. 303-316
LA: English
ER: M (Marine)
AB: Studies of benthic foraminifera in surface sediments of the Arctic, epicontinental Barents Sea, show several indications of calcium carbonate dissolution. Low values of calcium carbonate correspond to low ratios of calcareous/agglutinating foraminifera, planktic/benthic foraminifera, high ratios of living/dead foraminifera, corroded calcareous foraminifera, and high numbers of exposed organic linings of foraminifera. Dissolution increases eastwards and northwards in the study area. We suggest that the dissolution is caused by the presence of dense, cold, saline and CO sub(2)-rich bottom water, which is linked to sea-ice production and the position of the Oceanic Polar Front. We also think calcium carbonate dissolution in this area indicates a sink for atmospheric CO sub(2).
AN: 3638838

                                                                    507 of 1521  
TI: Nitrogen uptake, dissolved organic nitrogen release, and new production
AU: Bronk,-D.A.; Glibert,-P.M.; Ward,-B.B.
AF: Dep. Marine Sci., Univ. Georgia, Athens, GA 30602, USA
SO: SCIENCE-WASH. 1994 vol. 265, no. 5180, pp. 1843-1852
LA: English
ER: M (Marine); B (Brackish)
AB: In oceanic, coastal, and estuarine environments, an average of 25 to 41 percent of the dissolved inorganic nitrogen (NH sub(4) super(+) and NO sub(3) super(-)) taken up by phytoplankton is released as dissolved organic nitrogen (DON). Release rates for DON in oceanic systems range from 4 to 26 nanogram-atoms of nitrogen per liter per hour. Failure to account for the production of DON during nitrogen-15 uptake experiments results in an underestimate of gross nitrogen uptake rates and thus an underestimate of new and regenerated production. In these studies, traditional nitrogen-15 techniques were found to underestimate new and regenerated production by up to 74 and 50 percent, respectively. Total DON turnover times, estimated from DON release resulting from both NH sub(4) super(+) and NO sub(3) super(-) uptake, were 10  plus or minus  1, 18  plus or minus  14, and 4 days for oceanic, coastal, and estuarine sites, respectively.
AN: 3638660

                                                                    508 of 1521  
TI: Trace gas emissions from Canadian peatlands and the effect of climatic change
AU: Moore,-T.R.
AF: Dep. Geogr., McGill Univ., 805 Sherbrooke St. W, Montreal, PQ H3A 2K6, Canada
SO: WETLANDS 1994 vol. 14, no. 3, pp. 223-228
LA: English
ER: F (Freshwater)
AB: The emission of three trace gases, nitrous oxide, carbon dioxide, and methane, from peatlands is examined, identifying the primary controls and the potential effect of climatic change on emission rates. Nitrous oxide emission from natural peatlands is small and tied to the cycling of nitrogen but increases upon disturbance such as drainage. Peatlands generally act as a sink for carbon dioxide, but they convert from a sink to a source upon drainage. Methane emissions are controlled primarily by position of the water table, with secondary controls of temperature and trophic status of the peat. Canadian and other northern peatlands play a moderately important role in the global methane budget. Climate change, such as increases in temperature and precipitation predicted by 2 x CO sub(2) scenarios, may result in increased emissions of nitrous oxide, decreased carbon dioxide storage, and reduced methane emissions from Canadian peatlands.
AN: 3635612

                                                                    509 of 1521  
TI: The future of research in Canadian peatlands: A brief survey with particular reference to global change
AU: Gorham,-E.
AF: Dep. Ecol., Evol. and Behav., Univ. Minnesota, St. Paul, MN 55108, USA
SO: WETLANDS 1994 vol. 14, no. 3, pp. 206-215
LA: English
ER: F (Freshwater)
AB: Suggestions are made for future research on Canadian peatlands under several headings: distribution across the country, landscape features, environmental factors (hydrology, microclimatology, perma-frost, and fire), ecosystem properties (productivity, decomposition, biogeochemical cycling, and microbial activity), biotic characteristics (flora and fauna, including rare and threatened species), and paleoecological background. This evaluation points out the need for studies of peatland restoration. In addition, it is important to follow present models of excellence for future study and to train a new generation of researchers in multidisciplinary research.
AN: 3635610

                                                                    510 of 1521  
TI: (Interconnected research 'Case Study Harz': Pollutant burden, reaction of the ecosphere, and water quality. Final reports).
OT: Verbundforschung Fallstudle Harz: Schadstoffbelastung, Reaktion der Oekosphaere und Wasserqualitaet. Abschlussberichte
CA: Goettingen Univ. (FRG). Forschungszent. Waldoekosysteme-Waldsterben
SO: 1990 230 pp
LA: German
ER: F (Freshwater)
AB: The interconnected research 'Case Study Harz' investigates interdisciplinary questions of pollutant burden, mechanisms of deposition, reactions of the ecosphere and the resulting water quality in the catchment areas under observation. The increasing acidification of waters leads to a mobilization of heavy metals from existing lake sediments through extraction of cations. Against the background of a geochemical and hydrochemical survey and documentation, linkages in the field of action of pollutant deposition, pollutant transport and the effect of pollutants on aquatic biological communities are investigated and standards for action required in the future are assessed. Particularly important are questions of the relevance and informative value of biological indicators (Overall record from three individual records). (JH). [Contracts BMFT 0339069A, BMFT 0339069B. In German. Berichte des Forschungszentrums Waldoekosysteme. Reihe B, v. 19.] (DBO)
AN: 3633624

                                                                    511 of 1521  
TI: Simulation analysis of moored fluorometer time series from the Mid-Atlantic Bight during 1987-1990
AU: Walsh,-J.J.
CA: South Florida Univ., St Petersburg (USA). Dep. of Marine Science
SO: REP.-U.S.-DEP.-ENERGY 1990 42 pp
RN: DOE/ER/60285-4 (DOEER602854)
LA: English
ER: M (Marine)
AB: The goal of the previous research during 1987-1990 within the DOE (Department of Energy) Shelf Edge Exchange Processes (SEEP) program in the Mid-Atlantic Bight was to understand the physical and biogeochemical processes effecting the diffusive exchange of the proxies of energy-related, by-products associated with particulate matter between estuarine, shelf, and slope waters on this continental margin. As originally envisioned in the SEEP program plan, SEEP-III would take place at Cape Hatteras to study the advective exchange of materials by a major boundary current. One problem of continuing interest is the determination of the local assimilative capacity of slope waters and sediments off the eastern seaboard of the US to lengthen the pathway between potentially harmful energy by-products and man. At basin scales, realistic specification of the lateral transport by western boundary currents of particulate matter is a necessary input to global models of carbon/nitrogen cycling. Finally, at these global scales, the generic role of continental margins in cycling greenhouse gases, e.g. CO(sub 2), CH(sub 4), and N(sub 2)O, is now of equal interest. This continuing research of model construction and evaluation within the SEEP program focuses on all three questions at local, regional, and basin scales. Results from SEEP-I and II are discussed as well as plans for SEEP-III. [Contract FG05-85ER60285 Sponsored by Department of Energy, Washington, DC. Portions of this document are illegible in microfiche products.] (DBO)
AN: 3633609

                                                                    512 of 1521  
TI: Precipitation of carbonate minerals by microorganisms: Implications for silicate weathering and the global carbon dioxide budget
AU: Ferris,-F.G.; Wiese,-R.G.; Fyfe,-W.S.
AF: Dep. Geol., Univ. Toronto, 22 Russell ST., Toronto, ON M5S 3B1, Canada
SO: GEOMICROBIOL.-J. 1994 vol. 12, no. 1, pp. 1-13
LA: English
ER: B (Brackish); F (Freshwater)
AB: Direct light and electron microscopic studies show that cyanobacterial cells serve as nucleation sites for carbonate mineral precipitation in a variety of fresh to saline-alkaline lakes on the Cariboo Plateau in central British Columbia, Canada, and in mineralized crusts on weathered basalt in Iceland. The carbonate minerals found in association with the cyanobacteria were extremely fine-grained, and invariably occurred on the external surfaces of the cells. Carbonate mineralogy was variable, ranging from calcite to magnesite, depending on differences in lake and groundwater chemistry (i.e., saturation state of the water with respect to individual carbonate minerals). In microcosm experiments, phototrophic cyanobacterial increased alkalinity and the degree of oversaturation with respect to calcite. Calculated values for the saturation state of calcite and magnesite in Cariboo Plateau natural waters exhibited two distinct trends, with (1) high magnesite saturation values in areas where the weathering of magnesium olivine-rich basalt bedrock determines water chemistry, and (2) high calcite saturation values where bedrock is a mix of basic lava flows, limestone, argillite, and chert. Similar calculations for Iceland show that cold surface waters are generally oversaturated with respect to calcite, as expected for the weathering of calcium plagioclase-rich larva. These observations of microbial carbonate precipitation in the Caribou Plateau region of British Columbia, Canada, and on the Budarhaun larva plain in Iceland suggest that weathering of silicate minerals in bedrock is biogeochemically coupled to the deposition of carbonate minerals by microorganisms. This process may provide a sink for atmospheric carbon dioxide in terrestrial environments.
AN: 3632683

                                                                    513 of 1521  
TI: Release rates of trace elements and protein from decomposing planktonic debris. 2. Copepod carcasses and sediment trap particulate matter
AU: Reinfelder,-J.R.; Fisher,-N.S.*; Fowler,-S.W.; Teyssie,-J.-L.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: J.-MAR.-RES. 1993 vol. 51, no. 2, pp. 423-442
LA: English
ER: M (Marine)
AB: In experiments designed to relate the release kinetics of various elements with that of protein from biogenic particles,  super(110m)Ag,  super(241)Am,  super(109)Cd,  super(60)Co,  super(75)Se and protein were measured over time in radiolabeled copepod carcasses and particles caught in unpoisoned sediment traps (mostly zooplankton fecal pellets and amorphous marine snow). Log-linear release rate constants (k) of  super(110m)Ag,  super(241)Am,  super(109)Cd, and  super(60)Co from carcasses ranged from 0.079/d for  super(60)Co at 2 degree C to 0.130/d for  super(109)Cd at 15 degree C, and did not vary significantly with temperature.  super(75)Se was lost most rapidly from copepod carcasses at 2 degree C, with k = 0.168/d; however, at 15 degree C,  super(75)Se was in two compartments, with 56% in a rapidly exchanging pool (k = 0.391/d) and 44% in a slowly exchanging pool (k = 0.107/d). Protein displayed loss from two compartments at both temperatures. At 2 degree C, protein was lost slowly (k = 0.065/d) for 1 wk, after which it was released from the carcasses very rapidly (k = 0.245/d). At 15 degree C, however, the loss of protein from carcasses was more rapid over the first 2 d (k = 0.627/d) than thereafter (k = 0.127/d).
AN: 3632674

                                                                    514 of 1521  
TI: Cadmium versus phosphate in the world ocean
AU: de-Baar,-H.J.W.; Saager,-P.M.; Nolting,-R.F.; van-der-Meer,-J.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: MAR.-CHEM. 1994 vol. 46, no. 3, pp. 261-281
LA: English
ER: M (Marine)
AB: Cadmium (Cd) is one of the best studied trace metals in seawater and at individual stations exhibits a more or less linear relation with phosphate. The compilation of all data from all oceans taken from over 30 different published sources into one global dataset yields only a broad scatterplot of Cd versus phosphate. However, the smaller high-quality dataset obtained by rigorous selection of only those stations with uniform Cd/PO sub(4)-ratio in the deep waters, provides a consistent global description of the deep (> 1000 m) waters. The deep Cd/PO sub(4)-ratio increases from about 0.18 x 10 super(-3) in the subarctic North Atlantic to about 0.33-0.35 x 10 super(-3) in the northern Indian and Pacific Oceans, in accordance with increasing phosphate content, i.e. age, of the deep water. The increasing Cd/PO sub(4)-ratio with age (and phosphate) of the deep water masses is a function of the coupling between biogeochemical cycling and deep water circulation. Changes in the latter, for example during a glacial period, inevitably lead to significant shifts in the Cd/PO sub(4) relationship of seawater. Currently, the global distribution of the Cd/PO sub(4)-ratio in surface, thermocline and deep waters is consistent with preferential biogeochemical removal of Cd versus phosphate from surface waters. The net result for Cd/PO sub(4) is not dissimilar to the preferential surface removal of  super(12)C over  super(13)C driving the deep distribution of the dissolved  super(12)C/ super(13)C-ratio, although for Cd/PO sub(4) the underlying mechanism is obviously very different and not well understood.
AN: 3632524

                                                                    515 of 1521  
TI: Level and fate of trace metals in the Lagoon of Venice (Italy)
AU: Martin,-J.-M.; Huang,-Wei-Wen; Yoon,-Yi-Yong
AF: Inst. Biogeoch. Mar., URA-CNRS 386, Ec. Norm. Super., 1, Rue Maurice Arnoux, F-92120 Montrouge, France
SO: MAR.-CHEM. 1994 vol. 46, no. 4, pp. 371-386
LA: English
ER: M (Marine)
AB: This paper presents the first results of dissolved (total concentration and hydrophobic fraction) and particulate trace metals (core sediment and suspended matter) in the Lagoon of Venice. Both the particulate and dissolved trace metal concentrations are comparable with those measured in pristine rivers and non-contaminated seawater. In the mixing zone between the Silone channel water and the Adriatic seawater, Pb, Zn, Ni, Fe and Cd behave conservatively, indicating the absence of any significant removal or mobilization processes, Cu is significantly released from the particulate to the dissolved form. The mobilization of Cu is associated with the intense production of macroalgae and phytoplankton in the lagoon. The C18 Sep-Pak column extraction method has been used to isolate the hydrophobic organic fraction of dissolved trace metals. This fraction increases in the following order: Cd, Pb < Fe < Zn < Ni < Cu. A first estimate of total dissolved trace metals input to the lagoon of Venice shows that the atmospheric fluxes are more important than the riverine one's for all studied trace metals.
AN: 3630885

                                                                    516 of 1521  
TI: Iron photochemistry in seawater from the Equatorial Pacific
AU: Johnson,-K.S.; Coale,-K.H.; Elrod,-V.A.; Tindale,-N.W.
AF: Moss Landing Mar. Lab., P.O. Box 450, Moss Landing, CA 95039, USA
SO: MAR.-CHEM. 1994 vol. 46, no. 4, pp. 319-334
LA: English
ER: M (Marine)
AB: The photochemistry of iron in surface waters, and its implications to iron bioavailability, was examined on two cruises to the equatorial Pacific. Decktop incubations were performed with equatorial seawater to which iron was added in various chemical forms. Results showed clear diurnal patterns in measurable iron levels, with the highest levels occurring midday. These results are consistent with a model of iron cycling involving the photo-reductive dissolution of colloidal iron and its subsequent oxidation and biological uptake of dissolved iron(III). Model calculations were based on independently determined rate constants. We suggest that photochemical reactions may have a significant impact on iron availability to phytoplankton in the open ocean.
AN: 3630843

                                                                    517 of 1521  
TI: Increased coccolith production by coccolithophorid algae cultures enriched with dissolved inorganic carbon
AU: Takano,-H.; Takei,-R.; Manabe,-E.; Burgess,-J.G.; Matsunaga,-T.
AF: Tokyo Univ. Agric. and Technol., Koganei, Tokyo 184, Japan
CO: 3. International Marine Biotechnology Conference, Tromsoe, Norway, 7-12 Aug 1994
SO: 3RD-INTERNATIONAL-MARINE-BIOTECHNOLOGY-CONFERENCE:-PROGRAM,-ABSTRACTS-AND-LIST-OF-PARTICIPANTS. International-Advisory-Comm.-of-the-Int.-Marine-Biotechnology-Conference-1994,-Tromsoe-Norway TROMSOE-NORWAY TROMSOE-UNIVERSITY 1994 p. 50
LA: English
ER: M (Marine)
AB: Coccolithophorids are unicellular planktonic marine algae which produce elaborate structures called coccoliths which consist of scales or plates of CaCO sub(3). Coccoliths are made from calcium ions and bicarbonate ions present in sea water by the coccolithophorid algae. These ions are present in seawater as a result of lime stone and silicate stone weathering. Huge blooms of coccolithophorid algae often occur in the world's oceans and are an important aspect of the global carbon cycle and the recycling of CaCO sub(3). We have chosen coccolithoporid algae as model organisms to investigate biomineralization and have focussed on the ecological significance of CaCO sub(3) recycling. To determine of the biological factors limiting coccolith formation by Emiliania huxleyi, we investigated the effect of bicarbonate and calcium ion concentrations on coccolith formation. We demonstrated that enrichment of Eppley's medium with dissolved inorganic carbon (DIC) affected both coccolith formation (calcification) and cell growth (photosynthesis). Coccolith formation was enhanced to a greater extent than cell growth. Moreover, high-density culture of E. huxleyi was carried out by supplying sufficient DIC, calcium ions and nutrients to the cells. A maximum yield of coccolith particles of 0.61 g/l per day was obtained.
AN: 3630187

                                                                    518 of 1521  
TI: Biogeochemical transformations of nitrogen and phosphorus -- a pelagic submodel for the Baltic Sea
AU: Savchuk,-O.; Wulff,-F.
AF: State Oceanogr. Inst., St. Petersburg Branch, 23d Line, 2A, 199026, St. Petersburg, Russia
SO: SYST.-ECOL.-CONTRIB. 1993 no. 1, 50 pp
LA: English
ER: M (Marine); B (Brackish)
AB: A sub-model of the biogeochemical processes that drive the nitrogen and phosphorus cycles in the pelagic ecosystem of the Baltic Sea has been developed. It includes four levels of ecosystem structure - inorganic, organic, autotrophic, and heterotrophic variables and descriptions of physical, chemical and biological processes. The numerical experiments show plausible behaviour as well as reasonable reactions to changes in the parameters and in the driving forces, considering the constraint of a submodel. Our conclusion from this sub model development is that we have now created a basic structure describing the pelagic transformations of both nitrogen and phosphorus, useful in an overall model of the biogeochemical cycles of these elements in the Baltic. However, these processes of the pelagic community are intimately coupled to physical events and interactions with the sediments are of utmost importance in the shallow Baltic. Therefore, further development of the model must first include an integration with hydrodynamic and sediment submodels and then the addition of certain critical processes (nitrogen fixation, phosphate sorption-desorption).
AN: 3627899

                                                                    519 of 1521  
TI: Enzymatic models for estimating decomposition rates of particulate detritus
AU: Sinsabaugh,-R.L.; Osgood,-M.P.; Findlay,-S.
AF: Biol. Dep., Univ. Toledo, Toledo, OH 43606, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1994 vol. 13, no. 2, pp. 160-169
LA: English
ER: F (Freshwater)
AB: The authors evaluated a new statistical method that estimates POM mass loss rates from indices of microbial enzyme activity. Litter bags containing benthic POM in three size ranges--Fine (F) 0.063-0.25 Medium (M) 0.25-1 and Coarse (C) 1-4 mm--were placed in a eutrophic woodland stream in June 1992. Over a 6-mo period, samples were collected and analyzed for mass loss and the activities of seven extracellular enzymes involved in the degradation of holocellulose, chitin, and polyphenolic compounds. In-situ POM samples were collected concurrently and assayed for the same suite of enzyme activities. In all cases, mass loss was related to cumulative enzyme activity; however, apparent enzymatic degradation efficiencies were generally lower for MPOM and EPOM (= MFPOM) than for CPOM by factors of 1.5-7.
AN: 3627897

                                                                    520 of 1521  
TI: Vibrios in the marine and estuarine environment
AU: Colwell,-R.R.
AF: Univ. Maryland Biotechnol. Inst., 3021 Hartwork Rd., Suite 550, College Park, MD 20740, USA
CO: 3. International Marine Biotechnology Conference, Tromsoe, Norway, 7-12 Aug 1994
SO: 3RD-INTERNATIONAL-MARINE-BIOTECHNOLOGY-CONFERENCE:-PROGRAM,-ABSTRACTS-AND-LIST-OF-PARTICIPANTS. International-Advisory-Comm.-of-the-Int.-Marine-Biotechnology-Conference-1994,-Tromsoe-Norway TROMSOE-NORWAY TROMSOE-UNIVERSITY 1994 p. 92
LA: English
ER: M (Marine)
AB: Microbial populations of the estuarine, coastal, and marine environment have been under study for ca. 100 years, tracing to oceanographic voyages set to map and chart the physical, chemical, and biological parameters of the world oceans. Very early in marine microbiology it was discovered that many of those organisms which could be readily isolated from seawater and sediment were members of the Vibrionacae. In earlier classifications. Vibrionacae included both Vibrio and Aeromonas. Recent work on rRNA sequencing and DNA/DNA hybridization has shown that the Vibrionacae is separate and distinct taxonomically from the Aeromonadacae. Vibrios are readily cultivatable from seawater, marine animals, and seaweeds, leading to the hypothesis that vibrios comprise a dominant component of the microbial community structure of the marine environment. However, more recent work using direct detection of nucleic acid sequences (to determine the presence of organisms not yet cultivatable) demonstrated that there may be other species numerically in greater abundance. Nevertheless, the genus Vibrio includes organisms which are widely distributed in the marine environment. Some species are pathogenic for fish and shellfish, as well as for humans (e.g. Vibrio cholerae, Vibrio vulnificus, Vibrio parahaemolyticus, etc.). The role of vibrios in the marine environment has been shown to include biodegradation, nutrient regeneration, and biogeochemical cycling. Many species of vibrios are luminescent and a number are also capable of fixing nitrogen. Vibrios are associated with plankton, notably zooplankton. Recently, it has been possible to monitor species by fluorescent tagging of gene and antibody probes. Thus, global dispersion and distribution of microorganisms and seasonality shifts can now be monitored. Seasonality of Vibrio species, both in temperate and semi-tropical environments has been demonstrated. Autoecological principles, at the microbial level, and microbial diversity can be better appreciated by mapping species, such as Vibrio, in estuaries and the ocean.
AN: 3627802

                                                                    521 of 1521  
TI: Deep bacterial biosphere in Pacific Ocean sediments
AU: Parkes,-R.J.; Cragg,-B.A.; Bale,-S.J.; Getliff,-J.M.; Goodman,-K.; Rochelle,-P.A.; Fry,-J.C.; Weightman,-A.J.; Harvey,-S.M.
AF: Dep. Geol., Univ. Bristol, Bristol BS8 1RJ, UK
SO: NATURE 1994 vol. 37, no. 6496, pp. 410-413
LA: English
ER: M (Marine)
AB: Although around 70% of the Earth's surface is marine, little is known about the microbiology of underlying sediments, which can be more than a kilometre deep. Selective degradation of organic matter within sediments over geological time profoundly affects the chemical composition of the ocean and atmosphere. Microbial processes have a fundamental role in surface sediments, but despite geochemical evidence, their significance in deeper sediments has not been established. Here we report the discovery of viable sediment bacterial populations at five Pacific Ocean sites to depths > 500 m. Bacterial distributions and activities are commensurate with geochemical changes. Bacterial profiles with depth are remarkably consistent, and deviations can be linked to specific environmental factors. The rate of decline in these populations indicates that bacteria are present to even greater depths. These bacteria, some of which are unique, must have a profound effect on deep-sediment diagenetic processes, and their presence considerably extends the biosphere.
AN: 3627411

                                                                    522 of 1521  
TI: Carbon dioxide supersaturation in the surface waters of lakes
AU: Cole,-J.J.; Caraco,-N.F.; Kling,-G.W.; Kratz,-T.K.
AF: Inst. Ecosystem Stud., Cary Arboretum, Millbrook, NY 12545, USA
SO: SCIENCE-WASH. 1994 vol. 265, no. 5178, pp. 1568-1570
LA: English
ER: F (Freshwater)
AB: Data on the partial pressure of carbon dioxide (CO sub(2)) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within  plus or minus  20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure of CO sub(2) averaged 1036 microatmospheres, about three times the value in the overlying atmosphere, indicating that lakes are sources rather than sinks of atmospheric CO sub(2). On a global scale, the potential efflux of CO sub(2) from lakes (about 0.14 x 10 super(15) grams of carbon per year) is about half as large as riverine transport of organic plus inorganic carbon to the ocean. Lakes are a small but potentially important conduit for carbon from terrestrial sources to the atmospheric sink.
AN: 3627404

                                                                    523 of 1521  
TI: Carbon dynamics in a forested peatland in north-eastern Ontario, Canada
AU: Charman,-D.J.; Aravena,-R.; Warner,-B.G.
AF: Dep. Geogr. Sci., Univ. Plymouth, Plymouth, Devon PL4 8AA, UK
SO: J.-ECOL. 1994 vol. 82, no. 1, pp. 55-62
LA: English
ER: F (Freshwater)
AB: The long-term carbon accumulation rate in a forested peatland in north-east Ontario was examined in relation to gas production and factors which control carbon transport. Plots of cumulative total mass and cumulative carbon mass against calibrated radiocarbon age estimates when applied to an existing model of peat accumulation, suggest that only very slow decay is occurring within the catotelm. Gas samples collected from depth show that both carbon dioxide and methane are present. Accelerator mass spectrometry (AMS) radiocarbon analysis yields age estimates of both gases which are between 500 and 2000 years younger than conventional age estimates on adjacent peat. It is suggested that this is due to the downward transport of younger carbon, probably as part of the dissolved organic carbon (DOC) in pore waters. High tritium content of peat pore water at depth indicates the presence of water recharged during the last 40 years and therefore supports this hypothesis. Hydrological data from piezometers confirms the existence of hydraulic gradients for vertical water movement and shows that the direction of flow varies seasonally. The results indicate that the internal carbon dynamics of peatlands are more complex than has previously been thought and that hydrology may be an important factor in the supply of source carbon for anaerobic decay.
AN: 3627400

                                                                    524 of 1521  
TI: On the balance of hydrocarbon compounds in Lake Baikal.
OT: O balanse uglevodorodnykh soedinenij v ozere Bajkal
AU: Snytko,-V.A.; Afonina,-T.E.
SO: IZV.-RGO 1994 vol. 126, no. 3, pp. 65-69
LA: Russian
ER: F (Freshwater)
AB: The paper presents data on the production-destruction of autochthonous hydrocarbons and on the input and transformation of allochthonous (terrigenous) and technogenous hydrocarbons in different areas of the lake. Tabulated data on the balance of hydrocarbons in the lake are provided.
AN: 3626993

                                                                    525 of 1521  
TI: Physical and biological controls on carbon cycling in the Equatorial Pacific
AU: Murray,-J.W.; Barber,-R.T.; Roman,-M.R.; Bacon,-M.P.; Feely,-R.A.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: SCIENCE-WASH. 1994 vol. 266, no. 5182, pp. 58-65
LA: English
AB: The Equatorial Pacific is the largest oceanic source of carbon dioxide to the atmosphere and has been proposed to be a major site of organic carbon export to the deep sea. Study of the chemistry and biology of this area from 170 degree  to 95 degree W suggests that variability of remote winds in the western Pacific and tropical instability waves are the major factors controlling chemical and biological variability. The reason is that most of the biological production is based on recycled nutrients; only a few of the nutrients transported to the surface by upwelling are taken up by photosynthesis. Biological cycling within the euphotic zone is efficient, and the export of carbon fixed by photosynthesis is small. The fluxes of carbon dioxide to the atmosphere and particulate organic carbon to the deep sea were about 0.3 gigatons per year, and the production of dissolved organic carbon was about three times as large. The data establish El Nino events as the main source of interannual variability.
AN: 3622879

                                                                    526 of 1521  
TI: Retention of sulfur in lake sediments
AU: Urban,-N.R.
AF: Lake Res. Lab., Swiss Fed. Inst. for Water Resour. and Water Pollut. Control (EAWAG/ETH), CH-6047 Kastanienbaum, Switzerland
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ENVIRONMENTAL-CHEMISTRY-OF-LAKES-AND-RESERVOIRS. Baker,-L.A.-ed. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237 pp. 323-369
ST: ADV.-CHEM.-SER. vol. 237
LA: English
ER: F (Freshwater)
AB: Measurements of S cycling in Little Rock Lake, Wisconsin, and Lake Sempach, Switzerland, are used together with literature data to show the major factors regulating S retention and speciation in sediments. Retention of S in sediments is controlled by rates of seston (planktonic S) deposition, sulfate diffusion, and S recycling. Data from 80 lakes suggest that seston deposition is the major source of sedimentary S for approximately 50% of the lakes; sulfate diffusion and subsequent reduction dominate in the remainder. Concentrations of sulfate in lake water and carbon deposition rates are important controls on diffusive fluxes. Diffusive fluxes are much lower than rates of sulfate reduction, however. Rates of sulfate reduction in many lakes appear to be limited by rates of sulfide oxidation. Much sulfide oxidation occurs anaerobically, but the pathways and electron acceptors remain unknown. The intrasediment cycle of sulfate reduction and sulfide oxidation is rapid relative to rates of S accumulation in sediments. Concentrations and speciation of sulfur in sediments are shown to be sensitive indicators of paleolimnological conditions of salinity, aeration, and eutrophication.
AN: 3619718

                                                                    527 of 1521  
TI: Mass fluxes and recycling of phosphorus in Lake Michigan. Role of major particle phases in regulating the annual cycle
AU: Shafer,-M.M.; Armstrong,-D.E.
AF: Water Chem. Program, Water Sci. and Eng. Lab., Univ. Wisconsin, Madison, WI 53706, USA
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ENVIRONMENTAL-CHEMISTRY-OF-LAKES-AND-RESERVOIRS. Baker,-L.A.-ed. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237 pp. 285-322
ST: ADV.-CHEM.-SER. vol. 237
LA: English
ER: F (Freshwater)
AB: Biogeochemical cycling of phosphorus in a water column in southern Lake Michigan was examined, and the significance of major particle phases to the annual mass flux and recycling of phosphorus was assessed. Comparison of 1982-1983 total P and total filtrable P concentrations with data from 1990-1991 and other published data showed little change. The measured annual primary flux of P to the sediment surface reflected rapid sedimentation of both allochthonous particles and spring diatom production. Diatoms were the dominant vector of P to the sediment surface. Terrigenous phases and autochthonous calcite were also significant. More than half of the mixed-period diatom P demand was provided by colloidal and particulate P, nearly 60% of diatom-associated P was recycled within the water column, and 55-58% of total primary P flux was recycled at the sediment surface. Ultimately 2.2% of C and 2.7% of P became incorporated into recent sediments. The amount of P supplied by resuspension was relatively small compared with water-column standing pools and major flux vectors. With its relatively long residence, the response time for P changes with respect to loading should be on the order of 5-15 years.
AN: 3619714

                                                                    528 of 1521  
TI: Ecosystem-scale experiments. The use of stable isotopes in fresh waters
AU: Kling,-G.W.
AF: Dep. Biol., Univ. Michigan, Ann Arbor, MI 48109-1048, USA
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ENVIRONMENTAL-CHEMISTRY-OF-LAKES-AND-RESERVOIRS. Baker,-L.A.-ed. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237 pp. 91-120
ST: ADV.-CHEM.-SER. vol. 237
LA: English
ER: F (Freshwater)
AB: Experimental studies using additions of stable isotopes of nitrogen and carbon to an arctic lake indicated that new primary production rather than terrestrial detritus supports most animals in the planktonic food web and to a lesser degree in the benthic food web. The lake was divided by a curtain, and one half was fertilized with N and P through a 6-week experiment.  super(15)NH sub(4)Cl was added to both sides to label algae; terrestrial detritus remained unlabeled. Although nutrients cycled more quickly in the fertilized treatment, the trophic pathways of nitrogen flow were unaltered by fertilization. The retention time of nitrogen in the ecosystem was about 3 years in both control and fertilized treatments.  super(13)C-leucine additions to mesocosms indicated that phytoplankton make direct use of amino acids and that some macrozooplankton derive nutrition from the microbial food web.
AN: 3619689

                                                                    529 of 1521  
TI: Environmental chemistry of lakes and reservoirs
AU: Baker,-L.A.-(ed.)
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ADV.-CHEM.-SER. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237, 627 pp
LA: English
ER: F (Freshwater)
AB: This book explores a broad range of research dealing with the environmental chemistry of lakes and reservoirs. Both it and the symposium on which it is based were developed with four goals in mind. The first was to include a wide spectrum of topics, ranging from trace metal cycling and nutrient biogeochemistry to organic geochemistry. Second, there was an emphasis on timeliness, with an effort to include only work that was coming into full fruition, neither preliminary nor overwrought. Third, the book was to have a distinctly practical orientation reflecting the background of the editor, an environmental engineer. Finally, this volume was intended to reach a broad audience, including not only chemists, but also environmental engineers and biologists; scientists involved in practical aspects of water pollution, as well as those with a theoretical bent. The chapters are divided into four groups. The first section emphasizes methodological advances in studies of lake geochemistry. The second section examines the cycling and distribution of major elements (C, N, S, O, and P) in aquatic systems. The third section focuses on the behavior of trace metals, with an emphasis on processes that control their solubility and transport. The last section deals with several organic contaminants.
AN: 3619671

                                                                    530 of 1521  
TI: Enhanced calcification in the coccolithophorid Emiliania huxleyi (Haptophyceae) under phosphorus limitation
AU: Paasche,-E.; Brubak,-S.
AF: Sect. Mar. Bot., Dep. Biol., Univ. Oslo, P.O. Box 1069, Blindern, 0316 Oslo, Norway
SO: PHYCOLOGIA 1994 vol. 33, no. 5, pp. 324-330
LA: English
ER: M (Marine)
AB: The effect of phosphorus limitation on calcification in the coccolithophorid Emiliania huxleyi (Lohmann) Hay et Mohler was investigated by chemical Ca and C analyses, as well as in short-term  super(14)C uptake experiments. The latter made use of a newly developed microdiffusion method to separate  super(14)C in coccolith carbonate from photosynthetically assimilated  super(14)C. In comparison with exponentially growing cells in a nutrient-replete medium, cells grown in P-limited chemostats at half the maximum growth rate produced c. 60% more CaCO sub(3) relative to organic carbon. In the short-term incubations, cells from P-limited chemostats showed a relative increase in the capacity for calcification under reduced irradiance and in the dark, Nutrient effects on calcification are of potential interest in considerations of the impact of E. huxleyi blooms on the sea-air CO sub(2) interchange, and they deserve further study.
AN: 3616744

                                                                    531 of 1521  
TI: Minimal effect of iron fertilization on sea-surface carbon dioxide concentrations
AU: Watson,-A.J.; Law,-C.S.; Van-Scoy,-K.A.; Millero,-F.J.; Yao,-W.; Friedderich,-G.E.; Liddicoat,-M.I.; Wanninkhof,-R.H.; Barber,-R.T.; Coale,-K.H.
AF: Plymouth Mar. Lab., Prospect Place, West Hoe, Plymouth PL1 3DH, UK
SO: NATURE 1994 vol. 371, no. 6493, pp. 143-145
LA: English
ER: M (Marine)
AB: It has long been hypothesized that iron concentrations limit phytoplankton productivity in some parts of the ocean. As a result, iron may have played a role in modulating atmospheric CO sub(2) levels between glacial and interglacial times, and it has been proposed that large-scale deposition of iron in the ocean might be an effective way to combat the rise of anthropogenic CO sub(2) in the atmosphere. As part of an experiment in the equatorial Pacific Ocean, we observed the effect on dissolved CO sub(2) of enriching a small (8 x 8 km) patch of water with iron. We saw significant depression of surface fugacities of CO sub(2) within 48 hours of the iron release, which did not change systematically after that time. But the effect was only a small fraction ( similar to  10%) of the CO sub(2) drawdown that would have occurred had the enrichment resulted in the complete utilization of all the available nitrate and phosphate. Thus artificial fertilization of this ocean region did not cause a very large change in the surface CO sub(2) concentration, in contrast to the effect observed in incubation experiments, where addition of similar concentrations of iron usually results in complete depletion of nutrients. Although our experiment does not necessarily mimic all circumstances under which iron deposition might occur naturally, our results do not support the idea that iron fertilization would significantly affect atmospheric CO sub(2) concentrations.
AN: 3616672

                                                                    532 of 1521  
TI: River mouths and lagoons as a buffer zone for matter transport from land to the Black Sea.
OT: Ust'ya rek i limany kak bufernaya zona dlya potoka veshchestv s sushi v Chernoe more
AU: Shil'-krot,-G.S.
AF: Inst. Geogr. RAN, Moscow, Russia
SO: IZV.-RAN-GEOGR.-PROC.-RUSS.-ACAD.-SCI.-GEOGR. 1994 no. 2, pp. 100-111
LA: Russian
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The paper is a review of original and literature data on the fate of chemical pollutants (heavy metals, pesticides) in the ecosystems of water bodies of the northwestern Black Sea coast including river mouths and lagoons of various types. Data on the content of trace elements in water, macrophytes and bottom sediments in the estuaries of the Danube and Dnieper R. and in some coastal lagoons are provided in tabular form.
AN: 3616623

                                                                    533 of 1521  
TI: The uptake of iodate by marine phytoplankton
AU: Moisan,-T.A.; Dunstan,-W.M.; Udomkit,-A.; Wong,-G.T.F.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, CA 92093-0218, USA
SO: J.-PHYCOL. 1994 vol. 30, no. 4, pp. 580-587
LA: English
ER: M (Marine)
AB: Several studies have suggested that phytoplankton play a role in the iodine cycle. Using a short-term incubation technique for determining the uptake of iodate by phytoplankton, cultures of Thalassiosira oceanica Hasle, Skeletonema costatum (Greville) Cleve, Emiliania huxleyi (Lohmann) Hay and Mohler, and Dunaliella tertiolecta Butcher were found to be capable of assimilating iodate at rates ranging from 0.003 to 0.24 nmol IO sub(3) super(-)/ mu g chlorophyll a/h. The kinetics for the uptake of iodate can be modeled, and the similarity between the model and experimental results suggests that there is a steady state between iodate uptake and release of dissolved iodine from the cells, presumably in the form of iodide. Two experiments were conducted in the Sand Shoal Inlet of the Cobb Bay estuary (37 degree 15' N, 75 degree 50'W). The uptake of iodate was 0.26 and 0.08 nmol IO sub(3) super(-)/ mu g chlorophyll a/h during high and low tide, respectively. Using field estimates based on measured levels of iodate in the estuary, we estimate that phytoplankton can take up as much as 3% of the ambient pool of iodate on a daily basis and the entire pool in about 1 month. Thus, phytoplankton can be a significant component of the global iodine cycle by mediating changes in the speciation of iodine in the marine environment.
AN: 3615857

                                                                    534 of 1521  
TI: Calcification rates of rapidly colonising bryozoans in Hauraki Gulf, northern New Zealand
AU: Smith,-A.M.; Nelson,-C.S.
AF: Dep. Mar. Sci., Univ. Otago, P.O. Box 56, Dunedin, New Zealand
SO: N.Z.-J.-MAR.-FRESHWAT.-RES. 1994 vol. 28, no. 2, pp. 227-234
LA: English
ER: M (Marine)
AB: Very little is known about calcification rates of bryozoans, despite their importance in modern temperate-latitude shelf carbonate sediments and in temperate limestones. Here we report the carbonate production rates for 19 species of bryozoans over 3, 9, and 12-month periods from a settling experiment in 14 m water depth at Cape Rodney, Hauraki Gulf. Based on the larger bryozoan colonies, estimates of calcification rate range from 25 to 740 mg CaCO sub(3)/y. Extrapolation of calcification rate to overall bryozoan sediment production is not straightforward, but a value of 24-240 g CaCO sub(3)/m/y for the sample site has been determined, equivalent to a sediment accumulation rate of 4-40 cm per 1000 years (ky). In reality, over a large shelf region both dilution by other organisms and a patchy areal distribution of living bryozoans would reduce these values to only a few cm k/y. The relatively low rates of accumulation deduced here are mainly consistent with the few other studies of bryozoan sedimentation in temperate waters, and also with those typically reported (1-3 cm k/y) for many occurrences of temperate bryozoan-rich limestones from the rock record.
AN: 3614738

                                                                    535 of 1521  
TI: Preservation of primary productivity signal in Antarctic fjord sediments: Andvord Bay, Antarctica
AU: Domack,-E.W.; Mashiotta,-T.A.; Venkatsen,-M.I.
AF: Geol. Dep., Hamilton Coll., Clinton, NY 13323, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 66-67
LA: English
ER: M (Marine)
AB: This study is an interdisciplinary investigation into the paleoproductivity of an antarctic fjord based on sedimentologic and biogeochemical studies of a 9-meter-long piston core. We collected core 22 from Andvord Bay (64 degree 49.625' S 62 degree 39.001' W) in early 1988 as part of R/V Polar Duke cruise III. The chronology of core 22 extends back for approximately the last 3,000 years as based upon a set of five radiocarbon ages that range in age from 2025  plus or minus  60 to 4480  plus or minus  75 (table 1). These data result in a linear accumulation rate of 0.305 centimeters per year and interval rates of 0.23 and 0.52 centimeters per year for the upper and lower portions of the core respectively.
AN: 3613140

                                                                    536 of 1521  
TI: Distribution and production of biogenic silica in the upper water column of the Ross Sea 1990-1992
AU: Nelson,-D.M.; Gordon,-L.I.
AF: Coll. Oceanogr., Oregon State Univ., Corvallis, OR 97330, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 72-74
LA: English
ER: M (Marine)
AB: During February and early March of 1992 we made the second cruise of an ongoing study of the cycling of biogenic silica in the Ross Sea. This work is part of a coordinated interdisciplinary effort to understand the biogeochemical cycling of organic and siliceous matter in the Antarctic, being conducted in collaboration with W.O. Smith, University of Tennessee (primary productivity and organic-matter cycling) R. B. Dunbar, Rice University (vertical fluxes of organic and siliceous material through the water column) and D.J. DeMaster, North Carolina State University (sediment accumulation and early digenesis of silica and carbon). In 1990 and 1992 sampling was performed from the R/V Polar Duke. In both years we collected data over the entire Ross Sea shelf, emphasizing transect about 600 kilometers in length extending eastward from the shore-fast ice near the Victoria Land coast.
AN: 3613137

                                                                    537 of 1521  
TI: The accumulation and regeneration of biogenic silica and organic carbon in Ross Sea sediments
AU: DeMaster,-D.J.; Pope,-R.H.; Smoak,-J.M.; Nittrouer,-C.A.; Pierson,-G.H.
AF: Dep. Mar., Earth, and Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 74-76
LA: English
ER: M (Marine)
AB: Accumulation rates and regeneration rates for biogenic silica and organic carbon are being measured in Ross Sea sediments. As part of a larger project examining biogeochemical fluxes in the waters and sediments of the Ross Sea, this research provide information that allows a comparison of surface biogenic production rates with biogenic accumulation rates in the seabed below. This study evaluates lateral transport of material based on data from current meters and transmissometers moored at three Ross Sea locations for a period of two years. In formal of this type is essential for an understanding of the oceanographic processes that control the recycling and accumulation of biogenic material in high-latitude environments. During February 1992 we conducted the concluding field program for the Ross Sea Project. Using the USCGC Polar Sea and the R/V Polar Duke, we successfully recovered our three moorings and occupied 146 stations. We collected sediment with a kasten corer and/or a spade box corer at 36 stations.
AN: 3613136

                                                                    538 of 1521  
TI: The movement of suspended materials in the Ross Sea
AU: Nittrouer,-C.A.; Pierson,-G.H.; Morrison,-J.M.; DeMaster,-D.J.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 77-79
LA: English
ER: M (Marine)
AB: Lateral fluxes of suspended materials are being investigated as part of a larger study to understand biogeochemical fluxes in the Ross Sea. The primary objective is to provide insight that can be used to evaluate models describing the fate of biogenic Si and carbon. In particular, the limitations on one-dimensional, vertical models are being examined in light of observed horizontal advection. Much of the suspended material in the Ross Sea is lithogenic sediment, and therefore a better understanding of general glacial-marine sedimentation is also being obtained.
AN: 3613135

                                                                    539 of 1521  
TI: Influence of terrestrial weathering on early diagenetic reactions in continental shelf sediments
AU: Aller,-R.C.
AF: Mar. Sci. Res. Cent., SUNY at Stony Brook, Stony Brook, NY 11794-5000, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 437-438
LA: English
ER: M (Marine)
AB: Much of the recent emphasis in studies of early diagenetic reactions is on the cycling of biogenic debris. Lithogenic particles, their properties and the processes that formed them are often given little consideration other than as a diluent. With the discovery of extensive hydrothermal systems, interest has also waned in the possible relationships of terrestrial weathering and potential reverse weathering processes during early diagenesis of marine sediments. Studies of Amazon Shelf deposits demonstrate that this lack of interest is unwarranted and that terrestrial weathering processes can apparently have major influences not only on authigenic silicate formation but on biogeochemical reaction balances and minor element export processes in continental shelf deposits.
AN: 3613134

                                                                    540 of 1521  
TI: Cobalt(II) oxidation by the marine manganese(II)-oxidizing Bacillus sp. strain SG-1
AU: Lee,-Yoon; Tebo,-B.M.*
AF: Mar. Biol. Res. Div., Scripps Inst. Oceanogr., Univ. California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0202, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1994 vol. 60, no. 8, pp. 2949-2957
LA: English
ER: M (Marine)
AB: The geochemical cycling of cobalt (Co) has often been considered to be controlled by the scavenging and oxidation of Co(II) on the surface of manganese [Mn(III,IV)] oxides or manganates. Because Mn(II) oxidation in the environment is often catalyzed by bacteria, we have investigated the ability of Mn(II)-oxidizing bacteria to bind and oxidize Co(II) in the absence of Mn(II) to determine whether some Mn(II)-oxidizing bacteria also oxidize Co(II) independently of Mn oxidation. We used the marine Bacillus sp. strain SG-1, which produces mature spores that oxidize Mn(II), apparently due to a protein in their spore coats. A method to measure Co(II) oxidation using radioactive  super(57)Co as a tracer and treatments with nonradioactive (cold) Co(II) and ascorbate to discriminate bound Co from oxidized Co was developed. SG-1 spores were found to oxidize Co(II) over a wide range of pH, temperature, and Co(II) concentration. Leucoberbelin blue, a reagent that reacts with Mn(III,IV) oxides forming a blue color, was found to also react with Co(III) oxides and was used to verify the presence of oxidized Co in the absence of added Mn(II). Co(II) oxidation occurred optimally around pH 8 and between 55 and 65 degree C. SG-1 spores oxidized Co(II) at all Co(II) concentrations tested from the trace levels found in seawater to 100 mM. Co(II) oxidation was found to follow Michaelis-Menten kinetics. An Eadie-Hofstee plot of the data suggests that SG-1 spores have two oxidation systems, a high-affinity-low-rate system and a low-affinity-high-rate system. SG-1 spores did not oxidize Co(II) in the absence of oxygen, also indicating that oxidation was not due to abiological Co(II) oxidation on the surface of preformed Mn(III,IV) oxides. These results suggest that some microorganisms may directly oxidize Co(II) and such biological activities may exert some control on the behavior of Co in nature. SG-1 spores may also have useful applications in metal removal, recovery, and immobilization processes.
AN: 3613099

                                                                    541 of 1521  
TI: Total epiphyte and epiphytic carbonate production on Thalassia testudinum across Florida Bay
AU: Frankovich,-T.A.; Zieman,-J.C.
AF: Southeast Environ. Res. Program, OE 148, Florida Int. Univ., Miami, FL 33199, USA
CO: 1992 Symp. on Florida Keys Regional Ecosystem, Miami, FL (USA), Nov 1992
SO: SYMPOSIUM-ON-FLORIDA-KEYS-REGIONAL-ECOSYSTEM.-NOVEMBER-1992. Prospero,-J.M.;Harwell,-C.C.-eds. 1994 vol. 54, no. 3 pp. 679-695
ST: BULL.-MAR.-SCI. vol. 54, no. 3
LA: English
ER: M (Marine)
AB: Previous investigations of epiphytic carbonate production have suggested that seagrass epiphytes are significant producers of calcium carbonate and may be a primary source of lime muds in Florida Bay. This study determined total epiphyte and epiphytic carbonate standing stocks and calculated minimum estimates of yearly production at seven sites within Florida Bay and one site oceanside of the northern Florida Keys. These sites span a larger geographical area of increased environmental variability than those of previous Florida Bay epiphyte studies which were conducted in areas where conditions are considered favorable for epiphyte production. Total epiphyte and epiphytic carbonate loads along with seagrass shoot density and productivity were measured during four periods between August 1991 and August 1992. Epiphyte composition, standing stock, and production all exhibited marked variation across Florida Bay. Calcifying epiphytes were dominant in Florida Bay, and their distribution and the distribution of epiphyte production appear to reflect differences in the physical characteristics of salinity and the variability thereof. Minimum estimates of annual epiphytic carbonate production range from 1.9 g CaCO sub(3)/m super(2)/yr to 282.7 g CaCO sub(3)/m super(2)/yr, a range lower than previous estimates. The differences between these estimates and previous ones are attributed to differences in environments and, to a lesser extent, differences in methodology.
AN: 3611547

                                                                    542 of 1521  
TI: Virus and bacteria abundances in the Drake Passage during January and August 1991
AU: Smith,-D.C.; Steward,-G.F.; Azam,-F.; Hollibaugh,-J.T.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093-0202, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 125-127
LA: English
ER: M (Marine)
AB: High abundances of viruses have recently been discovered in various oceanic regimes and this has led to the suggestion that viruses may have a profound effect on food-web dynamics. If so, then current views on biogeochemical cycles in the ocean will need to be modified. Whether viruses are present in the southern ocean and, if so, whether they are as abundant as in other areas has not previously been addressed. We used transmission electron microscopy (TEM) to examine water samples from transects in both the winter and the summer in order to determine the spatial and temporal distribution of viruses in the southern ocean and its relationship to the distribution of bacteria.
AN: 3611251

                                                                    543 of 1521  
TI: Dissolved humic substances of vascular plant origin in a coastal marine environment
AU: Moran,-M.A.; Hodson,-R.E.
AF: Dep. Mar. Sci., Univ. Georgia, Athens, GA 30602-2206, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 762-771
LA: English
ER: M (Marine)
AB: Bacterial decomposition of vascular plant detritus in coastal wetlands results in the conversion of particulate organic matter to dissolved form and causes the release of humic substances into the bulk dissolved organic carbon (DOC) pool. We found that 34% of the DOC accumulating during degradation of salt marsh grass (Spartina alterniflora) form coastal wetlands of the southeastern U.S. fits the definition of humic substances and that lignin is the primary source of the dissolved humic substances (66% of the total). Although marine bacterioplankton used the lignin-rich humic substances more slowly and less efficiently than other components of the DOC pool, a significant fraction (24%) of these substances was mineralized within 7 weeks. Concentrations of vascular plant biomarkers (lignin phenols) indicate that 11-75% of the dissolved humic substances on southeastern U.S. continental shelf is from vascular plant-dominated environments. Calculations indicate that about half this material is contributed by the coastal salt marshes and half by river export. Vascular plant influence was lower in the bulk DOC pool (2-38%), indicating that terrestrially derived material is harbored preferentially in the humic substances subcomponent of marine DOC.
AN: 3608498

                                                                    544 of 1521  
TI: Sulfate reduction and diffusion in sediments of Little Rock Lake, Wisconsin
AU: Urban,-N.R.; Brezonik,-P.L.; Baker,-L.A.; Sherman,-L.A.
AF: Lake Res. Lab., EAWAG, Kastanienbaum, CH-6047, Switzerland
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 797-815
LA: English
ER: F (Freshwater)
AB: Rates of sulfate diffusion and reduction were measured in sediments of Little Rock Lake, an oligotrophic, soft-water lake in northern Wisconsin. Laboratory measurements of kinetics of sulfate reduction found half-saturation constants (20-30  mu mol/liter) and Q sub(10) values (2.6) similar to values reported in the literature. Sulfate reduction under in situ conditions in sediment cores was limited by sulfate and followed similar uptake kinetics as in laboratory experiments. Some variation in kinetic parameters was evident as a function of location in the lake. No seasonal variation was observed in sulfate reduction rates in the lake sediments, and littoral and pelagic sites exhibited similar rates. Rates of sulfate reduction were much higher than fluxes of sulfate calculated from pore-water profiles. Pore-water profiles also indicated little difference in diffusive fluxes among pelagic and littoral sites and among seasons. The discrepancy between diffusive fluxes and sulfate reduction rates is ascribed to high rates of oxidation of reduced sulfur. Nonlinear rates of sulfate reduction and calculated turnover times sediment sulfide pools support the hypothesis that sulfide oxidation occurs nearly as rapidly as sulfate reduction.
AN: 3608491

                                                                    545 of 1521  
TI: Probabilistic uncertainty assessment of phosphorus balance calculations in a watershed
AU: Taskinen,-A.; Varis,-O.; Sirvioe,-H.; Mutanen,-J.; Vakkilainen,-P.
AF: Helsinki Univ. Technol., Lab. Hydrol. Water Resour. Manage., FIN-02150 Espoo, Finland
CO: 2. International Conference on Reservoir Limnology and Water Quality Management, Ceske Budejovice (Czech Rep.), 9-14 Aug 1992
SO: ECOL.-MODEL. 1994 vol. 74, no. 1-2, pp. 125-135
LA: English
ER: F (Freshwater)
AB: Water quality studies in reservoirs, rivers, lakes, and entire river basins include increasingly often mass balance calculations. In comparison with hydrological studies where water balance models are traditionally frequently used, water quality investigations are typically faced with essentially higher uncertainty. This study presents an approach to the assessment and propagation of this uncertainty, with a case study on a river reach with three point source polluters, substantial throughflow, and non-point components. A computational implementation using spreadsheets was used, which allows the use of probabilistic models in close contact with environmental data bases.
AN: 3608452

                                                                    546 of 1521  
TI: The biogeochemistry of hydrogen sulfide: Phytoplankton production in the surface ocean
AU: Brooks,-A.S.; Edgington,-D.N.
AF: Cent. Great Lakes Stud., Univ. Wisconsin, Milwaukee, WI 53201, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 941-948
LA: English
ER: M (Marine)
AB: Hydrogen sulfide can exist in oxic waters in the form of a dissolved gas, dissociated ions, dissolved metal sulfide complexes, and particulate metal sulfides. The sum of the dissolved species is termed total dissolved sulfide (TDS). In addition to the hydrolysis of carbonyl sulfide, it has been speculated that phytoplankton may produce TDS. We present results from preliminary culture studies which demonstrate that phytoplankton produce TDS and particulate acid-volatile sulfide (pAVS). The phylogenetic order of TDS + pAVS production (per unit cell volume) for the oceanic species examined is Synechococcus sp. > Emiliania huxleyi )  Pyramimonas obovata > Thalassiosira oceanica. Moreover, TDS and pAVS production increases when the concentrations of uncomplexed trace metals in culture media are also increased, suggesting metal detoxification via the formation of metal sulfide complexes.
AN: 3607914

                                                                    547 of 1521  
TI: Biogeochemical control of phosphorus cycling and primary production in Lake Michigan
AU: Walsh,-R.S.; Cutter,-G.A.; Dunstan,-W.M.; Radford-Knoery,-J.; Elder,-J.T.
AF: Dep. Oceanogr., Old Dominion Univ., Norfolk, VA 23529-0276, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 961-968
LA: English
ER: F (Freshwater)
AB: A 3-yr study in Lake Michigan has shown a 27 mmol P/m super(2) increase in the mass of total P (TP) in the water during spring when the lake is mixed from surface to sediment. This value is an order of magnitude greater than the annual P input from external sources. TP changed in concert with increases in chlorophyll a and organic N and decreases in nitrate and soluble Si. The concentration of soluble reactive PO sub(4) super(3) super(-) (SRP) remained relatively constant throughout the study. We hypothesize that the SRP concentration is maintained by a chemical equilibrium with calcium-phosphate species. The increased mass of TP arises from the sequestering of P by algae which displaces the chemical equilibrium and allows more P to be released to the water from the sediments. Solar irradiance and the duration of mixing determine the magnitude of the spring bloom and the demand for P that must be supplied through the flux of P from the sediments to the overlying water.
AN: 3607900

                                                                    548 of 1521  
TI: Phosphorus regeneration by Lake Michigan alewives in the mid-1970s
AU: Kraft,-C.E.
AF: Univ. Wisconsin Sea Grant Inst., Univ. Wisconsin, 2420 Nicolet Dr., Green Bay, WI 54311-7001, USA
SO: TRANS.-AM.-FISH.-SOC. 1993 vol. 122, no. 5, pp. 749-755
LA: English
ER: F (Freshwater)
AB: A bioenergetics model of fish growth was used to estimate phosphorus (P) cycling by the population of Lake Michigan alewives Alosa pseudoharengus in the mid-1970s. The mean annual standing stock of alewives during the mid-1970s contained 1,500 tonnes of phosphorus, representing a substantial pool of particulate phosphorus unavailable to algae. An estimated 12,000 tonnes of phosphorus were egested and excreted annually by the Lake Michigan alewife population. Over half of the alewife-regenerated phosphorus was produced by larvae and age-0 alewives, which inhabit the nearshore epilimnion during summer. Seasonal aggregations of alewives-the dominant component of the Lake Michigan fish community during the mid-1970s-could have served as an important medium of phosphorus regeneration in comparison with more traditionally reported vehicles such as zooplankton. Expressed volumetrically, alewives regenerated 0.22  mu g P/L/d during August, which is comparable to phosphorus regeneration rates previously estimated for Lake Michigan zooplankton. Use of a bioenergetics model provided a means to demonstrate that alewives played a substantial role in Lake Michigan phosphorus regeneration during the mid-1970s.
AN: 3606734

                                                                    549 of 1521  
TI: Chitin production by crustaceans in marine ecosystem.
OT: La production de chitine par les crustaces dans les ecosystemes marins
AU: Jeuniaux,-C.; Voss-Foucart,-M.-F.; Bussers,-J.-C.
AF: Lab. Morphol., Systematique et Ecol. Animales, Inst. Van Beneden, Quai Van Beneden, 22, B-4020 Liege, Belgium
CO: 1. European Crustacean Conference, Paris (France), 31 Aug-4 Sep 1992
SO: AQUAT.-LIVING-RESOUR. 1993 vol. 6, no. 4, pp. 331-341
LA: French
AB: Chitin is synthesized by numerous animal species, either unicellular organisms or metazoans, belonging mainly to zoological groups of the Coelomate Spiralia lineage. However, the produced chitin in marine ecosystems is principally by crustaceans. A comparative study of analytical data so far available allowed calculation of chitin biomass and chitin production values in some types of marine ecosystems, and thus estimation of the quantitative importance of chitin in the biogeochemical cycles of carbon and nitrogen. The main data so far available concerns mediterranean plankton in Calvi bay (Corsica), arctic and antarctic krill, lobster population on South African coasts, and infralittoral benthic communities growing on rocky substrates on Corsica coasts. In all these cases, chitin production was estimated roughly at 1g per year and per square meter of rocky substrate or sea surface. Taking into account these production values and the relative extent of the main marine ecosystems over the world, the total production of chitin due to marine crustaceans was estimated at about 2.3 billion metric tons per year.
AN: 3606433

                                                                    550 of 1521  
TI: Automated in situ observations of upper ocean biogeochemistry, bio-optics, and physics and their potential use for global studies
AU: Dickey,-T.D.; Granata,-T.C.; Taupier-Ietage,-I.
CA: University of Southern California, Los Angeles (USA)
SO: 1992 37 pp
LA: English
ER: M (Marine)
AB: The process controlling the flux of carbon in the upper ocean have dynamic ranges in space and time of at least nine orders of magnitude. These processes depend on a broad suite of inter-related biogeochemical, bio-optical, and physical variables. These variables should be sampled on scales matching the relevant phenomena. Traditional ship-based sampling, while critical for detailed and more comprehensive observations, can span only limited portions of these ranges because of logistical and financial constraints. Further, remote observations from satellite platforms enable broad horizontal coverage which is restricted to the upper few meters of the ocean. For these main reasons, automated subsurface measurement systems are important for the fulfillment of research goals related to the regional and global estimation and modeling of time varying biogeochemical fluxes. Within the past few years, new sensors and systems capable of autonomously measuring several of the critical variables have been developed. The platforms for deploying these systems now include moorings and drifters and it is likely that autonomous underwater vehicles (AUV's) will become available for use in the future. Each of these platforms satisfies particular sampling needs and can be used to complement both shipboard and satellite observations. In the present review, (1) sampling considerations will be summarized, (2) examples of data obtained from some of the existing automated in situ sampling systems will be highlighted, (3) future sensors and systems will be discussed, (4) data management issues for present and future automated systems will be considered, and (5) the status of near real-time data telemetry will be outlined. Finally, we wish to make it clear at the outset that the perspectives presented here are those of the authors and are not intended to represent those of the United States JGOFS program, the International JGOFS program, NOAA's C&GC program, or other global ocean programs.
AN: 3605132

                                                                    551 of 1521  
TI: Ocean time-series near Bermuda: Hydrostation S and the US JGOFS Bermuda Atlantic time-series study
AU: Michaels,-A.F.; Knap,-A.H.
SO: 1992 21 pp
LA: English
ER: M (Marine)
AB: Bermuda is the site of two ocean time-series programs. At Hydrostation S, the ongoing biweekly profiles of-temperature, salinity and oxygen now span 37 years. This is one of the longest open-ocean time-series data sets and provides a view of decadal scale variability in ocean processes. In 1988, the U.S. JGOFS Bermuda Atlantic Time-series Study began a wide range of measurements at a frequency of 14-18 cruises each year to understand temporal variability in ocean biogeochemistry. On each cruise, the data range from chemical analyses of discrete water samples to data from electronic packages of hydrographic and optics sensors. In addition, a range of biological and geochemical rate measurements are conducted that integrate over time-periods of minutes to days. This sampling strategy yields a reasonable resolution of the major seasonal patterns and of decadal scale variability. The Sargasso Sea also has a variety of episodic production events on scales of days to weeks and these are only poorly resolved. In addition, there is a substantial amount of mesoscale variability in this region and some of the perceived temporal patterns are caused by the intersection of the biweekly sampling with the natural spatial variability. In the Bermuda time-series programs, we have added a series of additional cruises to begin to assess these other sources of variation and their impacts on the interpretation of the main time-series record. However, the adequate resolution of higher frequency temporal patterns will probably require the introduction of new sampling strategies and some emerging technologies such as biogeochemical moorings and autonomous underwater vehicles.
AN: 3605040

                                                                    552 of 1521  
TI: JGOFS North Atlantic bloom experiment: An overview
AU: Ducklow,-H.W.
CA: Maryland Univ., Cambridge (USA). Horn Point Environmental Labs.
SO: 1992 23 pp
LA: English
ER: M (Marine)
AB: The North Atlantic Bloom Experiment (NABE) of JGOFS presents a unique opportunity and challenge to the data management community because of the diversity and large size of biogeochemical data sets collected. NABE was a pilot study for JGOFS and has also served as a pilot study within the U.S. NODC for management and archiving of the data sets. Here I present an overview to some of the scientific results of NABE, which will be published as an Introduction to a special volume of NABE results in Deep-Sea Research later this year. An overview of NABE data management is given elsewhere in the present report. This is the first collection of papers from the Joint Global Ocean Flux Study (JGOFS). Formed as an international program in 1987, JGOFS has four principal elements: modelling and data management, multidisciplinary regional process studies, a global survey of biogeochemical properties and long-term time series observatories. In 1989-1990 JGOFS conducted a pilot process study of the spring phytoplankton bloom the North Atlantic Bloom Experiment (NABE). JGOFS decided to conduct a large scale, internationally-coordinated pilot study in the North Atlantic because of its proximity to the founding nations of the project, the size and predictability of the bloom and its fundamental impact on ocean bio-geochemistry (Billett et al., 1983; Watson and Whitfield, 1985; Pfannkuche, 1992). In 1989, six research vessels from Canada, Germany. The Netherlands, the United Kingdom and the USA and over 200 scientists and students from more than a dozen nations participated in NABE. Some of their initial results are reported in this volume.
AN: 3605033

                                                                    553 of 1521  
TI: Data management for community research projects: A JGOFS case study
AU: Lowry,-R.K.
CA: Proudman Oceanographic Lab., Bidston (UK)
SO: 1992 23 pp
LA: English
ER: M (Marine)
AB: Since the mid 1980s, much of the marine science research effort in the United Kingdom has been focused into large scale collaborative projects involving public sector laboratories and university departments, termed Community Research Projects. Two of these, the Biogeochemical Ocean Flux Study (BOFS) and the North Sea Project incorporated large scale data collection to underpin multidisciplinary modeling efforts. The challenge of providing project data sets to support the science was met by a small team within the British Oceanographic Data Center (BODC) operating as a topical data center. The role of the data center was to both work up the data from the ship's sensors and to combine these data with sample measurements into online databases. The working up of the data was achieved by a unique symbiosis between data center staff and project scientists. The project management, programming and data processing skills of the data center were combined with the oceanographic experience of the project communities to develop a system which has produced quality controlled, calibrated data sets from 49 research cruises in 3.5 years of operation. The data center resources required to achieve this were modest and far outweighed by the time liberated in the scientific community by the removal of the data processing burden. Two online project databases have been assembled containing a very high proportion of the data collected. As these are under the control of BODC their long term availability as part of the UK national data archive is assured. The success of the topical data center model for UK Community Research Project data management has been founded upon the strong working relationships forged between the data center and project scientists. These can only be established by frequent personal contact and hence the relatively small size of the UK has been a critical factor. However, projects covering a larger, even international scale could be successfully supported by a network of topical data centers managing online databases which are interconnected by object oriented distributed data management systems over wide area networks.
AN: 3605014

                                                                    554 of 1521  
TI: Modelling chemico-biological cycles in the White Sea: Computation of seasonal carbon compounds variability.
OT: Modelirovanie khimiko-biologicheskikh tsiklov v Belom more: Reschet sezonnoj izmenchivosti soedinenij ugleroda
AU: Yakushev,-E.V.; Mikjajlovskij,-G.E.
AF: Inst. Okeanol., Moscow, Russia
SO: OKEANOLOGIYA 1994 vol. 34, no. 2, pp. 240-247
LA: Russian
ER: M (Marine)
AB: The paper describes a mathematical model developed to estimate the effect of marine biota on seasonal variations of carbon compounds. The model parametrizes chemico-biological processes, chemical transformation processes within the carbonate system, hydrophysical processes, water-air exchange and sedimentation. The model permitted computation of the range of seasonal variations in the carbonate system parameters and estimation of the separate contribution of hydrophysical (60%) and biological (40%) processes to this range. The effect of biota is mainly manifested as changes in pH during the spring bloom resulting in disturbance of the carbonate system balance, temporary increase of carbonate ion and decrease of free carbon dioxide content, which in turn causes anomalies in the seasonal variability of the intensity of carbon dioxide flux across the air-sea interface.
AN: 3604958

                                                                    555 of 1521  
TI: The release of phosphorus from oxygenated estuarine sediments
AU: Maher,-W.A.; DeVries,-M.
AF: Water Res. Cent., Univ. Canberra, P.O. Box 1, Belconnen, ACT 2616, Australia
SO: CHEM.-GEOL. 1994 vol. 112, no. 1-2, pp. 91-104
LA: English
ER: M (Marine)
AB: Grab samples were collected at the oxygenated sediment-water interface during August 1987 from eight stations along the longitudinal salinity gradient of the Beaulieu River Estuary, south-central England. The bulk sediment composition and phosphorus associations in the sediments were determined to identify the factors causing phosphorus concentrations and associations to vary in the sediments. Bulk sediment elemental composition and organic matter content were unrelated to sedimentary total P, although there was a correlation with percentage silt and clay. Sediment fractionation studies indicated that the majority of bound sedimentary P was associated with the Fe-Al-sesquioxide phases which were in turn closely related to extractable Fe and Mn. Experiments were performed to determine the effect of salinity, agitation, biological activity, addition of a carbon source and degree of water oxygenation on P exchange between the estuarine sediments and the overlying water column. Phosphorus adsorption was decreased in deoxygenated sediments, and those supplemented with a secondary carbon source or a mixture of biocides, indicating that both release from iron oxides in reducing conditions at low Eh and microbiological conditions can influence P exchange. P release, however, did not deplete a specific P-containing fraction, but led instead to a redistribution of P between various sedimentary phases after extended experimental incubation. Sedimentary oxygen demand produced by carbon sources must be considered for proper management of eutrophication problems.
AN: 3603318

                                                                    556 of 1521  
TI: Gulf of Mexico hydrocarbon seep communities. 11. Carbon isotopic fractionation during fatty acid biosynthesis of seep organisms and its implication for chemosynthetic processes
AU: Fang,-Jiasong; Abrajano,-T.A.; Comet,-P.A.; Brooks,-J.M.; Sassen,-R.; MacDonald,-I.R.
AF: Geochem. and Environ. Res. Group, Coll. Geosci., Texas A&M Univ., 833 Graham Rd., College Station, TX 77845, USA
SO: CHEM.-GEOL. 1993 vol. 109, no. 1-4, pp. 271-279
LA: English
ER: M (Marine)
AB: The individual fatty acids of mytilids and vestimentiferan (Escarpis sp.) from hydrocarbon seeps exhibit light  delta  super(13)C-values: from -56.9 to -49.0ppt for the mytilids and from -38.6 to -31.6ppt for the vestimentiferan. Unsaturated fatty acids have lighter  delta  super(13)C than saturated ones. The variations in  delta  super(13)C are up to 5.1-6.7ppt (mytilids) and 7.0ppt (vestimentiferan) within a single specimen. It is suggested that a kinetic isotopic effect in the biosynthesis of fatty acids and intermolecular isotope fractionation during fatty acid desaturation and elongation are responsible for the observed distribution pattern. Fatty acids are depleted in  super(13)C relative to the gills of the mytilids, whereas fatty acids of the vestimentiferan are enriched relative to trophosomes. The difference in  delta  super(13)C of fatty acids between mytilids and vestimentiferan reflects the differences in substrates (methane vs. CO sub(2)), and the different chemosynthetic processes of the invertebrates.
AN: 3603313

                                                                    557 of 1521  
TI: Data management for JGOFS: Theory and design
AU: Flierl,-G.R.; Bishop,-J.K.B.; Glover,-D.M.; Paranjpe,-S.
CA: Massachusetts Inst. of Technology, Cambridge (USA)
SO: pp. 229-249,
LA: English
ER: M (Marine)
AB: The Joint Global Ocean Flux Study (JGOFS), currently being organized under the auspices of the Scientific Committee for Ocean Research (SCOR), is intended to be a decade long internationally coordinated program. The main goal of JGOFS is to determine and understand on a global scale the processes controlling the time-varying fluxes of carbon and associated biogenic elements in the ocean and to evaluate the related exchanges with the atmosphere, sea floor and continental boundaries. "A long-term goal of JGOFS will be to establish strategies for observing, on long time scales, changes in ocean biogeochemical cycles in relation to climate change". Participation from a large number of U.S. and foreign institutions is expected. JGOFS investigators have begun a set of time-series measurements and global surveys of a wide variety of biological, chemical and physical quantities, detailed process-oriented studies, satellite observations of ocean color and wind stress and modeling of the biogeochemical processes. These experiments will generate data in amounts unprecedented in the biological and chemical communities; rapid and effortless exchange of these data will be important to the success of JGOFS.
AN: 3601553

                                                                    558 of 1521  
TI: Relation between inorganic nitrogen and phosphorus in Jiulongjiang Estuary and western Xiamen Harbour
AU: Chen,-Shuitu
AF: Fujian Inst. Oceanol., Xiamen 361012, People's Rep. China
SO: MAR.-SCI.-BULL.-HAIYANG-TONGBAO 1993 vol. 12, no. 5, pp. 26-32
LA: Chinese
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Based on the survey data of inorganic nitrogen and some species of phosphorus and other parameters from Jiulongjiang Estuary and western Xiamen Harbour from March 1987 to December 1988, the changes of the ratio of nitrogen to phosphorus is discussed in relation to primary productivity in the survey region. Nitrate and ammonium in the region had an influence on the geochemistry of phosphorus. N/P ratio was high with mean 36  similar to  64 except in spring and part of the estuary. Phosphorus, not nitrogen, was the limiting factor to phytoplanktonic growth. Higher nitrate content in the bottom layer hindered the release of phosphorus from surface sediment.
AN: 3601489

                                                                    559 of 1521  
TI: Isotopic tracers of nitrogen from atmospheric deposition to coastal waters
AU: Fogel,-M.L.; Paerl,-H.W.
AF: Carnegie Inst. Washington, Geophys. Lab., Washington, DC, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 233-236
LA: English
ER: M (Marine)
AB: Nitrogen deposition to global oceans from the atmosphere can be about two times that of natural riverine input. Even accounting for the increased loading of riverine nitrogen by anthropogenic inputs, total atmospheric deposition (AD) is essentially equal to that of riverine sources. Among growth-limiting nutrients, nitrogen plays a key role in regulating primary and secondary productivity both on regional and global scales. As such, proper identification and characterization of nitrogen sources and their impacts on nutrient flux and trophic utilization is of prime concern in understanding biogeochemical responses in coastal ecosystems.
AN: 3600149

                                                                    560 of 1521  
TI: Modelling the nitrogen cycle in the Channel: A first approach
AU: Hoch,-T.; Menesguen,-A.; Bentley,-D.
AF: IFREMER, Cent. Brest, Dir. Environ. Littoral, Lab. Chim. Model. Cycles Nat., B.P. 70, 29280 Plouzane, France
CO: Channel Symp.: Fluxes and Processes Within a Macrotidal Sea, Brest (France), 2-7 Sep 1992
SO: CHANNEL-SYMPOSIUM:-FLUXES-AND-PROCESSES-WITHIN-A-MACROTIDAL-SEA.#SYMPOSIUM-MANCHE:-FLUX-ET-PROCESSUS-A-L'-ECHELLE. Chardy,-P.;Cabioch,-L.-eds. 1993 vol. 16, no. 5-6 pp. 643-651
ST: OCEANOL.-ACTA vol. 16, no. 5-6
LA: English
ER: M (Marine)
AB: A simple model of the nitrogen cycle in the Channel is proposed. Based on the long-term circulation, this box-model permits the description of the spring phytoplankton bloom in the whole Channel. Spring western thermal stratification has not been taken into account; consequently, the earliest phytoplanktonic development is observed in the eastern Channel, followed by the western, deeper part. This model also shows the influence of nutrient supply from the rivers on the Channel ecosystem, and particularly the influence of the River Seine on the chlorophyll concentrations along the eastern French coast. Comparison of calculated data with measurements shows a fairly good agreement in the eastern Channel but discrepancies are encountered for the western part. These problems are discussed and improvements of the model are proposed.
AN: 3599835

                                                                    561 of 1521  
TI: Role of plankton on the biogeochemical cycle of cadmium and vanadium in the eastern area of the Bay of Seine: First results.
OT: Role du plancton dans le cycle biogeochimique du cadmium et du vanadium en baie de Seine orientale: Premiers resultats
AU: Miramand,-P.; Bentley,-D.; Guary,-J.C.; Brylinski,-J.M.
AF: Lab. Biogeochim. Mar. Inst. Natl. Sci. Tech. Mer, Conserv. Natl. Arts Metiers, B.P. 324, 50103 Cherbourg Cedex, France
CO: Channel Symp.: Fluxes and Processes Within a Macrotidal Sea, Brest (France), 2-7 Sep 1992
SO: CHANNEL-SYMPOSIUM:-FLUXES-AND-PROCESSES-WITHIN-A-MACROTIDAL-SEA.#SYMPOSIUM-MANCHE:-FLUX-ET-PROCESSUS-A-L'-ECHELLE. Chardy,-P.;Cabioch,-L.-eds. 1993 vol. 16, no. 5-6 pp. 625-632
ST: OCEANOL.-ACTA vol. 16, no. 5-6
LA: French
ER: M (Marine)
AB: Cd and V were analyzed in planktonic species (zooplankton and diatoms), in flocks and in total seston (suspended materials) collected at eleven stations for seven sampling periods in the eastern area of the Bay of Seine. Cd concentrations measured in planktonic species of the Bay of Seine are identical to those measured in other oceanic areas, but V concentrations are generally higher. In the conditions of sampling, the role of both planktonic species and flocks in the horizontal fluxes of Cd and V in the Bay of Seine appears not to be important (Cd) or negligible (V) compared to non-living materials (tripton). Nevertheless, this study should be continued in periods of diatom blooms. Flocks which present high Cd and V concentration probably have an important role in the biogeochemical cycle for both elements in the Bay of Seine.
AN: 3599833

                                                                    562 of 1521  
TI: Beaver influences on the long-term biogeochemical characteristics of boreal forest drainage networks
AU: Naiman,-R.J.; Pinay,-G.; Johnston,-C.A.; Pastor,-J.
AF: Cent. Streamside Stud., AR-10, Univ. Washington, Seattle, WA 98195, USA
SO: ECOLOGY 1994 vol. 75, no. 4, pp. 905-921
LA: English
AB: Beaver (Castor canadensis) affect biogeochemical cycles and the accumulation and distribution of chemical elements over time and space by altering the hydrologic regime. Aerial photograph analyses of beaver activities on the 298-km super(2) Kabetogama Peninsula, Minnesota, were coupled with site-specific studies of soil and pore water concentrations of nutrients (nitrogen, phosphorus) and other ions (potassium, calcium, magnesium, iron, sulfate, chloride), nitrogen cycling processes (nitrogen fixation and denitrification), and biophysical environmental variables (vegetation, temperature, organic matter, soil structure, pH, and oxidation-reduction potential). Our analyses demonstrate that beaver influence the distribution, standing stocks, and availability of chemical elements by hydrologically induced alteration of biogeochemical pathways and by shifting element storage from forest vegetation to sediments and soils. Over the 63 yr of aerial photo records (1927-1988), beaver converted 13% of the peninsula to meadows and ponds. We argue that the net effect of beaver activities has been to translocate chemical elements from the originally inundated upland forest vegetation to downstream communities and to pond sediments. Since 1927 beaver activities have augmented the standing stock of chemical elements in the organic horizons by 20-295%, depending on the element. These influences are spatially extensive and long lasting, affecting fundamental environmental characteristics of boreal forest drainage networks for decades to centuries.
AN: 3599777

                                                                    563 of 1521  
TI: The role of the blue mussel Mytilus edulis in the cycling of nutrients in the Oosterschelde Estuary (The Netherlands)
AU: Prins,-T.C.; Smaal,-A.C.
AF: Netherlands Inst. Ecol., Cent. Estuar. Coast. Ecol., Vierstr. 28, 4401 EA Yerseke, Netherlands
SO: THE-OOSTERSCHELDE-ESTUARY-THE-NETHERLANDS:-A-CASE-STUDY-OF-A-CHANGING-ECOSYSTEM. Nienhuis,-P.H.;Smaal,-A.C.-eds. 1994 vol. 282-283 pp. 413-429
ST: HYDROBIOLOGIA vol. 282-283
LA: English
ER: B (Brackish)
AB: The fluxes of particulate and dissolved material between bivalve beds and the water column in the Oosterschelde estuary have been measured in situ with a Benthic Ecosystem Tunnel. On mussel beds uptake of POC, PON and POP was observed. POC and PON fluxes showed a significant positive correlation, and the average C:N ratio of the fluxes was 9.4. There was a high release of phosphate, nitrate, ammonium and silicate from the mussel bed into the water column. The effluxes of dissolved inorganic nitrogen and phosphate showed a significant correlation, with an average N:P ratio of 16.5. A comparison of the in situ measurements with individual nutrient excretion rates showed that excretion by the mussels contributed 31-85% to the total phosphate flux from the mussel bed. Ammonium excretion by the mussels accounted for 17-94% of the ammonium flux from the mussel bed. The mussels did not excrete silicate or nitrate. Mineralization of biodeposition on the mussel bed was probably the main source of the regenerated nutrients. From the in situ observations net budgets of N, P and Si for the mussel bed were calculated. A comparison between the uptake of particulate organic N and the release of dissolved inorganic N (ammonium + nitrate) showed that little N is retained by the mussel bed, and suggested that denitrification is a minor process in the mussel bed sediment. On average, only 2/3 of the particulate organic P, taken up by the mussel bed, was recycled as phosphate. A net Si uptake was observed during phytoplankton blooms, and a net release dominated during autumn. It is concluded that mussel beds increase the mineralization rate of phytoplankton and affect nutrient ratios in the water column. A comparison of N regeneration by mussels in the central part of the Oosterschelde estuary with model estimates of total N remineralization showed that mussels play a major role in the recycling of nitrogen.
AN: 3599148

                                                                    564 of 1521  
TI: Patterns of hydrological exchange and nutrient transformation in the hyporheic zone of a gravel-bottom stream: Examining terrestrial-aquatic linkages
AU: Triska,-F.J.; Duff,-J.H.; Avanzino,-R.J.
AF: U.S. Geol. Surv., Water Resour. Div., 345 Middlefield Rd., Menlo Park, CA 94025, USA
SO: FRESHWAT.-BIOL. 1993 vol. 29, no. 2, pp. 259-274
LA: English
ER: F (Freshwater)
AB: The terrestrial-aquatic interface beneath a riparian corridor was investigated as a region of hydrological and biological control of nutrient flux. Subsurface flow paths were defined from the channel toward the riparian zone and also from the riparian zone toward the channel using tracer-injection studies. Dissolved oxygen (DO) concentration in the hyporheic zone ranged from < 1.0 to 9.5 mg/l due to permeability variations in bankside sediments. DO concentration was related to the proportion of stream water in the lateral hyporheic zone, indicating that the channel water was the DO source. Both nitrification potential and channel exchange decreased with distance from the channel and were absent at sites lacking effective exchange, due to low DO. Field amendment of ammonium to an aerobic flow path indicated nitrification potential under natural hydrological conditions.
AN: 3597862

                                                                    565 of 1521  
TI: Role of interaction zones between surface and ground waters in DOC transport and processing: Considerations for river restoration
AU: Vervier,-P.; Dobson,-M.; Pinay,-G.
AF: Cent. Ecol. des Ressources Renouvelables, UPR CNRS 8211, 29 rue Jeanne Marvig, 31055 Toulouse Cedex, France
SO: FRESHWAT.-BIOL. 1993 vol. 29, no. 2, pp. 275-284
LA: English
ER: F (Freshwater)
AB: A study of dissolved organic carbon (DOC), nitrates and total dissolved phosphorus (TDP) concentrations, conductivity and bacterial numbers was undertaken in subsurface water of the Garonne River (France) under low-flow conditions. The velocity of subsurface flow through a 300-m gravel bar, during this study, was less than 43 m day super(-1). DOC, nitrates and TDP concentrations, conductivity and bacterial numbers fluctuated within the gravel bar with no discernible spatial pattern. Bacterial abundance was correlated with DOC concentration. Results were compared to a previous study of the Stillaguamish River (U.S.A.). These studies provide evidence that gravel bars are important in the processing of DOC by bacteria in the subsurface water. Bacterial activity is, in turn, determined by sources of DOC from upstream at high discharge, and by patchy local microhabitats at low discharge.
AN: 3597859

                                                                    566 of 1521  
TI: [Biological indicators of environmental contamination.]
OT: Indicateurs biologiques de la contamination de l'environnement
AU: Garrigues,-P.-(ed.)
AF: Univ. Bordeaux 1, F-33405 Talence Cedex, France
SO: ANALUSIS 1994 vol. 22, no. 1, pp. M9-M29
LA: French
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Numerous studies were recently carried out to examine biochemical, physiochemical and histological changes, and to evaluate the exposure of organisms to contaminants. Chemical analysis of different compartments of the environment (air, soil, water, organisms) give information on the presence/absence of a chemical compound and upon its biogeochemical cycle, but they do not give information on the impact of the toxic substance on organisms. Ecotoxicological tests are often unable to inform the toxicologist because of the low level of contaminants in the environment. Analytical measures of a given contaminant may confirm or deny the use of a biochemical indicator of pollution. A review of these techniques is made in this collection of papers.
AN: 3596043

                                                                    567 of 1521  
TI: A comparison of organic matter sources, diagenesis and preservation in oxic and anoxic coastal sites
AU: Cowie,-G.L.; Hedges,-J.I.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 447-451
LA: English
ER: M (Marine)
AB: Sediment cores and water-column particulate samples (from month-long sediment trap deployments over full-year periods) were recovered from two coastal environments; Dabob Bay (Washington State, U.S.A.) and Saanich Inlet (British Columbia, Canada). Lignin phenol, neutral sugar and amino acid compositions were determined for all samples, as were organic carbon and nitrogen contents. The sampling and analytical strategies were designed to provide molecular-level information on seasonal trends in organic matter sources and fluxes, as well as on the nature and magnitude of diagenetic processes occurring both in the water column and underlying sediments.
AN: 3596013

                                                                    568 of 1521  
TI: Degradation and oligomerization of syringic acid by distinctive ecological groups of fungi
AU: Bergbauer,-M.
AF: Inst. Biochem. Molek. Biol., Abt. Bot. Mikrobiol. Chem., Technische Univ. Berlin, 1000 Berlin 10, Franklinstr. 29 OE 5/1, FRG
SO: MICROB.-ECOL. 1991 vol. 21, no. 1, pp. 73-84
LA: English
ER: F (Freshwater)
AB: Forty-four terrestrial and aeroaquatic and aquatic fungi, including fifteen species causing white-rot, four species causing brown-rot, and some species causing soft-rot of wood, were tested for their ability to degrade the monomer syringic acid, which is released during decay of angiosperm lignin. None of the white- or brown-rot species caused any detectable degradation of syringic acid under the test conditions, however, six typical white-rot fungi strongly oligomerized syringic acid, both with and without cosubstrate. The main polymerization product was identified as a 1,3-dimethylpyrogallol oligomer by  super(13)C-NMR. Other minor metabolic products were methylated and hydroxylated derivatives. Among the remaining fungi, Exophiala jeanselmei, Fusarium eumartii, and Paecilomyces variotii completely and rapidly degraded syringic acid (5 g/liter) within 48 to 100 hours. A further seven species were able to degrade syringic acid to some extent when glucose was added. Methylated and demethylated metabolic intermediates were identified by GC/MS.
AN: 3595831

                                                                    569 of 1521  
TI: Metabolic and structural changes in E. coli cells starved in seawater
AU: Papapetropoulou,-M.; Zoumbou,-K.; Nicolopoulou,-A.
AF: Environ. Microbiol. Div., Public Health Lab., Med. School, Univ. Patras, Greece
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K,-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-OF-RESEARCH-PROJECT-1992-1993.#CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K,-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROFETS-DE-RECHERCHE-1992-1993. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 76 pp. 39-56
ST: MAP-TECH.-REP.-SER. no. 76
LA: English
ER: M (Marine)
AB: Thirteen Escherichia coli strains of different biotype isolated from bench cultures were followed for metabolic and structural changes during starvation in seawater at different time (0,2,6,9,16,21 days of starvation). Additionally sensitivity to antibiotics of the starved E. coli cells was performed over time on Mueller-Hinton agar.  beta -Galactosidase activity of starved cells disappeared gradually with time. Nine (69.2%) of the E. coli strains lost the ability to decarboxylate lysine and seven (53.8%) to acidify melibiose. All E. coli strains acquired the ability to degrade gelatine at different time of starvation. Esterase 4, Esterase lipase, Leucine arylamidase and Lipase C14 increase during starvation while Alkaline and Acid phosphatase and Phosphoamidase decrease. Some of the strains lost their cytoplasmic proteins and in others the synthesis of the major outer membrane proteins was decreased. In one strain a large amount of 30 kDa proteins appeared. The sensitivity of E. coli strains to ampicillin, cephalothin, nalidixic acid, gentamicin, tobramycin, streptomycin and chloramphenicol increase slightly. In the case of tetracyclin, erythromycin, penicillin and vancomycin the difference in the diameter of zone of inhibition is minimum or zero. The traditionally used Bauer Kirby method has been proven to be inadequate for testing sensitivity of environmental strains. The understanding of the starvation-survival mechanism of pathogens related to Public Health is discussed.
AN: 3594876

                                                                    570 of 1521  
TI: [Gene expression in enteric bacteria in marine environments.]
OT: Expression genique chez les bacteries enteriques dans les conditions marines
AU: Gauthier,-M.J.; Breittmayer,-V.A.; Braux,-A.-S.
AF: INSERM Unite 303 "Mer et Sante", Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K,-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-OF-RESEARCH-PROJECT-1992-1993.#CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K,-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROFETS-DE-RECHERCHE-1992-1993. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 76 pp. 9-38
ST: MAP-TECH.-REP.-SER. no. 76
LA: French
ER: M (Marine)
AN: 3594875

                                                                    571 of 1521  
TI: The survival of human enteric viruses in seawater
AU: Bosch,-A.; Gray,-M.; Diez,-J.M.; Gajardo,-R.; Abad,-F.X.; Pinto,-R.M.; Sobsey,-M.D.
AF: Dep. Microbiol., Univ. Barcelona, 08028 Barcelona, Spain
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K,-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-OF-RESEARCH-PROJECT-1992-1993.#CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K,-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROFETS-DE-RECHERCHE-1992-1993. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 76 pp. 1-7
ST: MAP-TECH.-REP.-SER. no. 76
LA: English
ER: M (Marine)
AB: Human pathogenic viruses enter the marine environment primarily through the discharge of treated and untreated sewage into surface waters. Since current treatment practices do not provide virus-free effluents, enteric viruses are routinely discharged into estuarine and coastal waters. The critical question which arises, however, is whether or not these viruses can survive long enough and in high enough concentration to cause disease in individuals who are in contact with polluted recreational water or who consume contaminated seafood. The phenomenon that self purification processes are more pronounced in seawater than in river water has been reported by several authors. However, there appears to be no consensus on the nature of the factor(s) responsible for the virucidal capacity of seawater. Several observations demonstrate the potential involvement of native marine microorganisms in the inactivation of viruses in marine habitats, although data on the successful isolation of microorganisms with virucidal properties are scarce. Additionally, the ability of bacteria to inactivate viruses is usually lost while subculturing the bacteria in the laboratory. The present report deals with the effect of different types of seawater on the survival of human enteric viruses, and the influence of the presence of marine bacteria on the virucidal capacity of seawater.
AN: 3594874

                                                                    572 of 1521  
TI: Biogeochemical cycles of specific pollutants (activity K), survival of pathogens. Final reports on research project (1992-1993).
OT: Cycles biogeochemiques de polluants specifiques (activite K), survie des pathogenes. Rapports finaux sur les projets de recherche (1992-1993)
CA: UNEP Mediterranean Action Plan, Athens (Greece)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1993 no. 76, 65 pp
LA: English
ER: M (Marine)
AN: 3594873

                                                                    573 of 1521  
TI: The distribution of colloids in the North Atlantic and Southern Oceans
AU: Wells,-M.L.; Goldberg,-E.D.
AF: Inst. Mar. Sci., Earth and Mar. Sci. Build., Univ. California, Santa Cruz, CA 95064, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 2, pp. 286-302
LA: English
ER: M (Marine)
AB: The concentrations and size distributions of small (<200 nm) colloids were measured at three stations in the North Atlantic and two stations in the Southern Ocean. The stations were chosen to cover a range of oceanographically distinct regimes, from highly productive nearshore environments to oligotrophic open-ocean waters. Colloid number concentrations decreased appreciably from the surface to  similar to  150-m depth at three of these stations. Concentrations in deep waters of the North Atlantic were high but erratic, suggesting that colloid abundance is regulated by rapid rates of reactions. The colloids were mainly organic and their immediate sources appear to include both autotrophic and heterotrophic activity as well as sediment resuspension. Transmission electron microscope examination of colloid size distributions and morphology indicates that aggregation is the principal removal mechanism for these colloids. Evidence from the cumulative size spectra of small colloids indicates that colloid aggregation is most intense in vertically delineated zones near the surface, around the main thermocline ( similar to  1,000-1,500 m), and in bottom waters. These findings show that the marine colloidal state is abundant but discontinuous in both space and time throughout a wide range of oceanographic environments.
AN: 3594831

                                                                    574 of 1521  
TI: Reassessment of the oceanic residence time of phosphorus
AU: Ruttenberg,-K.C.
AF: Dep. Mar. Chem. and Geochem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 405-409
LA: English
ER: M (Marine)
AB: Phosphorus (P) is an essential nutrient for the growth of all organisms and is believed to limit marine productivity, especially on geologic time scales. As a result of the link between marine photosynthetic productivity and atmospheric CO sub(2), phosphorus along with other nutrients present in short supply in the euphotic zone have been cited as potential players in the ocean's role in climate change. This link has been referred to as the "nutrient-CO sub(2)" connection. Model simulations which aim to quantify the role of oceanic nutrient inventories in promoting or enhancing climate change rely on the most currently formulated element budgets for the ocean. In this paper significant modifications to the currently accepted marine phosphorus budget are proposed. The modified P budget presented here required a reassessment of phosphorus residence time in the ocean, and a concomitant review of the role of P as a potential player in climate change over glacial-interglacial time scales.
AN: 3592705

                                                                    575 of 1521  
TI: Sediment-trap experiments in the central and western Ross Sea, January and February 1990
AU: Dunbar,-R.B.; Mucciarone,-D.A.; Leventer,-A.
AF: Dep. Geol. Geophys., Rice Univ., Houston, TX 77251, USA
SO: ANTARCT.-J.-U.S. 1991 vol. 26, no. 5, pp. 115-117
LA: English
ER: M (Marine)
AB: As part of an interdisciplinary, multi-institutional study of the biogeochemical cycles of carbon and silicon on the Ross Sea continental shelf, we deployed both drifting and moored arrays of particle interceptor traps at three sites in the central and western Ross Sea during January and February, 1990. Particle transport and dissolution/degradation dynamics in the southern ocean water column control a variety of important processes including nutrient regeneration, delivery of food to benthic communities, and preservation of sediment records of climate change. Many features of the carbon and silicon cycles on the antarctic continental shelf are not observed in lower latitudes and appear to be controlled by a combination of unusual seasonality, great water depths, low temperatures, and high current energies. One of our goals is to establish budgets for surface production, vertical and horizontal transport, and seabed accumulation of important bioactive phases in this unique setting.
AN: 3592669

                                                                    576 of 1521  
TI: Phytoplankton sinking rates in the Ross Sea
AU: Close,-A.R.
AF: Grad. Progr. Ecol., Univ. Tennessee, Knoxville, TN 37996, USA
SO: ANTARCT.-J.-U.S. 1991 vol. 26, no. 5, pp. 151-152
LA: English
ER: M (Marine)
AB: As part of a coordinated, interdisciplinary study of the production of biogenic material at the surface, its flux and remineralization through the water column, and its accumulation in the sediments, we measured the sinking rates of suspended particulate matter in the Ross Sea in January and February 1990. Substantial deposits of diatoms occur in the sediments of the Ross Sea, and these deposits generally are composed of intact phytoplankton cells. One of our hypotheses in this program was that the vertical flux of phytoplankton from the ice-edge bloom was large relative to less productive regions, and we wanted to know whether this flux was continual or episodic in time (i.e., a large pulse of intact cells sink near the end of the growing season). If the latter were true, it would have significant implications for the biogeochemical cycles of biogenic elements (carbon, nitrogen, silicon) as well as food web dynamics.
AN: 3592662

                                                                    577 of 1521  
TI: Testing the microbial loop concept by comparing mesocosm data with results from a dynamical simulation model
AU: Baretta-Bekker,-J.G.; Riemann,-B.; Baretta,-J.W.,; Koch-Rasmussen,-E.
AF: Ecol. Modelling Cent., Joint Dep. Water Qual. Inst. and Danish Hydraul. Inst., Agern Alle 11, DK-2970 Hoersholm, Denmark
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 106, no. 1-2, pp. 187-198
LA: English
ER: M (Marine)
AB: Data from marine enclosures were compared with model results from the European Regional Seas Ecosystem Model (ERSEM). The simulation runs were performed with the December 1992 (V5.1) version of the pelagic submodel of ERSEM. The aim of the experiment was to verify the microbial loop as implemented in ERSEM against direct observations from marine enclosures. Initial conditions of the state variables for the model runs were derived from the same data. In general, the model results tracked the measured data indicating the model concept and implementation to be realistic. In contrast, the simulated concentrations of nitrate and phosphate in the nutrient-enriched bag stayed higher than observed, indicating the necessity of including mechanisms to allow for luxury uptake in the model description of the phytoplankton.
AN: 3592602

                                                                    578 of 1521  
TI: Phytoplankton dynamics in relation to the biogeochemical cycle of silicon in a coastal ecosystem of western Europe
AU: Ragueneau,-O.; De-Blas-Varela,-E.; Treguer,-P.; Queguiner,-B.; Del-Amo,-Y.
AF: URA CNRS 1513, Inst. Univ. Europeen de la Mer, Univ. de Bretagne Occidentale, BP452, F-29275 Brest Cedex, France
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 106, no. 1-2, pp. 157-172
LA: English
ER: M (Marine)
AB: The Bay of Brest, France, a typical semi-enclosed coastal ecosystem (159 km super(2)) of western Europe, was studied during spring 1992 with respect to the biogeochemical cycle of silicon. Three periods of nutrient and phytoplankton dynamics (chlorophyll a, biogenic silica, species compositon), were distinguished during spring 1992, each corresponding, respectively, to a bloom of Thalassiosira and Skeletonema costatum during early spring (April), Rhizosolenia during mid-spring (May) and Chaetoceros sociale during late spring (June). During each period the production of biogenic silica (the mean rate of spring biogenic silica production was 13 mmol Si/m super(2)/d), derived from  super(14)C primary production measurements, size fractionation experiments and appropriate Si:C ratios, has been compared with the sum of the silicic acid inputs to the bay originating from rivers, from the adjacent Iroise Sea and from the sediments.
AN: 3592600

                                                                    579 of 1521  
TI: [Causes and effects of nutrient accumulation in the Baltic Sea.]
OT: Ursachen und Folgen der Naehrstoffakkumulation in der Ostsee
AU: Nehring,-D.
AF: Inst. Ostseeforsch., Seestr. 15, D-18069 Rostock-Warnemuende, FRG
CO: Vortragsveranstaltung des Arbeitsausschusses fuer Abwasserfragen im DFW, Rostock (FRG), 12 Sep 1991
SO: ACTUAL-PROBLEMS-IN-POLLUTION-OF-THE-BALTIC-SEA.#AKTUELLE-PROBLEME-DER-VERSCHMUTZUNG-DER-OSTSEE. HAMBURG-FRG DEUTSCHER-FISCHEREI-VERBAND-E.V. 1991 no. 54 pp. 48-62
ST: ARB.-DTSCH.-FISCH.-VERB. no. 54
LA: German
ER: M (Marine); B (Brackish)
AB: Long-term changes concerning the nutrient load of phosphate and nitrate accumulation in the Baltic Sea from 1969 to 1977 are reported in this study in reference to growing eutrophic conditions. The cause and effect of this situation along with prefective measurements are discussed.
AN: 3592559

                                                                    580 of 1521  
TI: [Seasonal and long-term changes of chemical-hydrographic data in the Kiel Bight.]
OT: Saisonale und langzeitliche Veraenderungen chemisch-hydrographischer Parameter in der Kieler Bucht
AU: Hansen,-H.-P.
SO: BIOLOGICAL-MONITORING-OF-THE-BALTIC-SEA-IN-THE-INSTITUTE-OF-MARINE-SCIENCE-KIEL-1985-1992.#DAS-BIOLOGISCHE-MONITORING-DER-OSTSEE-IM-INSTITUT-FUER-MEERESKUNDE-KIEL-1985-1992. Duiker,-J.C.-ed. 1993 no. 240 pp. 2-31
ST: BER.-INST.-MEERESKD.-CHRISTIAN-ALBRECHTS-UNIV.-KIEL no. 240
LA: German
ER: M (Marine); B (Brackish)
AB: The purpose of this study is to compare different long-term data periods for the hydrographic and chemical parameters in the Baltic Sea in order to find the causes in the degradation of this environment.
AN: 3592526

                                                                    581 of 1521  
TI: Patterns and processes in detritus-based stream systems
AU: Graca,-M.A.S.
AF: Dep. Zool. e Inst. Invest. Agua, Univ. Coimbra, 3049 Coimbra Codex, Portugal
SO: LIMNOLOGICA 1993 vol. 23, no. 2, pp. 107-114
LA: English
ER: F (Freshwater)
AB: Allochthonous organic matter entering streams has been referred to as a major source of energy for aquatic systems. Aquatic hyphomycetes are important in the release of nutrients locked in the structural plant material, apparently due to their ability to grow at low water temperatures. Detritus is ingested by animals only after colonization by these fungi. Some key processes in detritus-based stream systems are still unknown. For example, are the fungi the feeding target of detritivores or are the fungi important only as leaf modifiers? Why do detritivores select for particular detritus-colonizing fungal species? Do fungi play any role in the elimination of plant alellochemicals? All generalizations on detritus-based stream systems are derived from research carried out in meridional areas and little is known of its validity in warmer regions such as the mediterranean or tropical forests. It is therefore important to evaluate (1) the relative importance of allochthonous energy input in other systems and (2) the processes governing its entry into the aquatic food webs. Moreover, virtually nothing is known about how the systems may be affected by habitat modifications (e.g. afforestation of drainage basins with exotic species such as Pinus in Scotland and Wales or Eucalyptus in the Mediterranean and Brazil). Woodlands in general and tropical forests in particular are being destroyed at an alarming rate.
AN: 3592499

                                                                    582 of 1521  
TI: Nitrogen and energy loss in the marine teleost Lithognathus mormyrus (Linnaeus)
AU: Cockcroft,-A.C.; Du-Preez,-H.H.
AF: Zool. Dep., Univ. Port Elizabeth, PO Box 1600, Port Elizabeth 6000, South Africa
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1990 vol. 140, no. 3, pp. 159-171
LA: English
ER: M (Marine)
AB: Nitrogen excretion and assimilation efficiencies in Lithognathus mormyrus (Linnaeus), a marine teleost present in high-energy surf zones in Algoa Bay, South Africa, were determined under controlled laboratory conditions at 15, 20 and 25 degree C. Ammonia was the major form of nonfaecal nitrogen excreted by starved and fed L. mormyrus. Urea and amino acids were secondary excretory products. Ammonia excretion rates were temperature independent and the excretion rates of fed fish were significantly higher than starved fish at 20 and 25 degree C but not at 15 degree C. The mass component (b) of the mass/ammonia excretion equation was temperature independent and ranged from 0.590 to 0.669 and from 0.670 to 0.767 for starved and fed fish, respectively. The mean percentage of food energy lost via the dissolved nonfaecal excretory products (exogenous plus endogenous) was 4.12%. Assimilation efficiencies ranged from 71.89 to 98.78% for dry matter and from 96.89 to 99.88% on an energy basis. The combined nonfaecal and faecal energy loss was calculated at 10.11% of the ingested energy. The omnivorous ichthyofauna present in the surf zone ecosystem recycle 33 g N/m strip/yr. This constitutes <1% of total phytoplankton nitrogen requirements.
AN: 3591251

                                                                    583 of 1521  
TI: Nitrogen interchanges generated by biogeochemical processes in a Galician ria
AU: Prego,-R.
AF: Inst. Invest. Mar. (CSIC), Eduardo Cabello, 6, E-36208 Vigo, Spain
SO: MAR.-CHEM. 1994 vol. 45, no. 1-2, pp. 167-176
LA: English
ER: M (Marine); B (Brackish)
AB: The biogeochemistry of nitrogen in the ria of Vigo is approached on the basis of a box model which allows for calculation of the physical transport of nitrate, nitrite, ammonium and organic nitrogen, and the fluxes caused by photosynthesis, remineralisation and sedimentation of nitrogen. The ria of Vigo receives between 4 and 22 mol/s from exterior coastal water, a flux far greater than that of freshwater. The balance of organic nitrogen indicates that there is always an exportation to the outer ria, in the range of 0.5 to 5 mol/s. The enrichment of the incoming water is produced by photosynthetic activity in spring and summer, and by river and sediment contributions in winter. Inorganic nitrogen is only exported during the rainy season, when phytoplankton activity is low. During the rest of the year, the ria retains 3.5 mol/s of the total nitrogen received. As a result of these fluxes, the residence time of nitrogen in the ria varies between 15 and 97 days. In the spring and summer of 1986, photosynthesis of the ria of Vigo consumed 7.4 mol/s, 24% of which was derived from the remineralisation in the aphotic zone in the ria. Part of the synthesised PON is sedimented and remineralised on the continental shelf, or is reintroduced into the ria. This plays an important role in fertilising the area, not considered until now in Galician rias. Both remineralisations supply 40% of the inorganic nitrogen to the euphotic layer in the ria.
AN: 3591023

                                                                    584 of 1521  
TI: Stable isotopic structure of aquatic ecosystems
AU: Wada,-E.; Kabaya,-Y.; Kurihara,-Y.
AF: Mitsubishi Kasei Inst. Life Sci., 11 Minamiooya, Machida, Tokyo 194, Japan
SO: J.-BIOSCI. 1993 vol. 18, no. 4, pp. 483-499
LA: English
ER: B (Brackish)
AB: Isotopic biogeochemical and ecological structure can provide a new dimension for understanding material flows, and the simultaneous function and structure of an ecosystem. Distributions of delta  super(13)C and delta  super(15)N for biogenic substances in the Nanakita River estuary involving Gamo Lagoon in Japan were investigated to construct isotope biogeochemical and ecological structure for assessing fate and transfer of organic matter, and food web structure. The isotopic framework of the ecosystem was successfully described in a delta  super(15)N-delta  super(13)C map. In this estuary the variations of isotope ratios of biogenic substances were clearly explained by the mixing of land-derived organic matter, and marine-derived organic matter. A trophic-level effect of  super(15)N enrichment was clearly observed. Organisms were classified into three groups depending upon the contribution of land-derived organic matter in a food chain. Almost all biota except mollusca in the lagoon depend on organic matter of marine origin. The contributions of both land and marine organic matter were comparable for mollusca in the lagoon.
AN: 3584947

                                                                    585 of 1521  
TI: The global insignificance of telluric input of dissolved trace metals (Cd, Cu, Ni and Zn) to ocean margins
AU: Martin,-J.M.; Thomas,-A.J.
AF: Inst. Biogeochim. Mar., URA CNRS 386, Ecole Norm. Super., 1 rue M. Arnoux, F-92120 Montrouge, France
CO: 12. Int. Symp. "Chemistry of the Mediterranean", Rovinj (Croatia), 18-23 May 1992
SO: 12TH-INTERNATIONAL-SYMPOSIUM-"CHEMISTRY-OF-THE-MEDITERRANEAN". Kniewald,-G.;Branica,-M.-eds. 1994 vol. 46, no. 1-2 pp. 165-178
ST: MAR.-CHEM. vol. 46, no. 1-2
LA: English
ER: M (Marine)
AB: A tentative mass-balance of dissolved trace metals (TM) in the global ocean margin is presented. Comparison of the various TM sources demonstrates the limited contribution of the telluric source (riverine and atmospheric), as compared to the oceanic input by upwelled water: marine inputs exceed telluric inputs by a factor of 2-3.5 for Cu, 2-7 for Zn, and of about 10 for Cd and Ni. Diagenetic TM release from deposited sediments, although likely for Cu and Zn, could not be quantified without ambiguity. Following intense water exchanges, TM are exchanged between the ocean margin and the open ocean very rapidly, and their short residence time is similar to the margin water residence time, i.e. about 1.3 yr.
AN: 3584561

                                                                    586 of 1521  
TI: Use of SAR in regional methane exchange studies
AU: Morrissey,-L.A.; Livingston,-G.P.; Durden,-S.L.
AF: NASA Ames Res. Cent., MS 242-4, Moffett Field, CA 94035-1000, USA
SO: INT.-J.-REMOTE-SENS. 1994 vol. 15, no. 6, pp. 1337-1342
LA: English
ER: F (Freshwater)
AB: Significant sources of uncertainty in global trace gas budgets are due to lack of knowledge concerning the areal and temporal extent of source and sink areas. Synthetic aperture radar (SAR) is particularly suited to studies of northern ecosystems because of its all-weather operating capability which enables the acquisition of seasonal data. As key controls on methane exchange, the ability to differentiate major vegetation communities, inundation, and leaf area index (LAI) with satellite and airborne SAR data would increase the accuracy and precision of regional and seasonal estimates of methane exchange. The utility of SAR data for monitoring key control on methane emissions from Arctic and boreal ecosystems is examined.
AN: 3581080

                                                                    587 of 1521  
TI: Organic volatile sulfur in lakes ranging in sulfate and dissolved salt concentration over five orders of magnitude
AU: Richards,-S.R.; Rudd,-J.W.M.; Kelly,-C.A.
AF: Macdonald Coll. McGill Univ., Dep. Microbiol., 21,111 Lakeshore Rd., Ste. Anne-de-Bellevue, PQ H9X 3V9, Canada
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 3, pp. 562-572
LA: English
ER: F (Freshwater)
AB: Organic volatile sulfur compounds (VSCs) were studied in six hypersaline lakes (southern Saskatchewan) and in dilute wetland ponds (Hudson Bay Lowlands, HBL). [SO sub(4) super(2-)] (0.0002-64 g/liter) and salt concentration (0.003-370 g/liter) ranged over 5 orders of magnitude. Organic VSC concentrations in ponds and lakes with [SO sub(4) super(2-)] < 7 g/liter were similar to those measured previously in freshwater lakes. Lakes with > 20 g SO sub(4) super(2-)/liter, however, had VSC concentrations several orders of magnitude higher. Dimethyl sulfide (DMS) was the dominant species, reaching a concentration of 3,050 nM in one salt lake - the highest concentration yet recorded. Carbonyl sulfide (COS), methanethiol (MSH), dimethyl disulfide (DMDS), and carbon disulfide (CS sub(2)) were also detected. In the salt lakes, [DMS], [MSH], and [total] VSC] were positively correlated (P < 0.05) to [SO sub(4) super(2-)] but not to dissolved salt concentration (P < 0.05). The estimated mean atmospheric flux from the salt lakes ranged from 2 to 590  mu mol S/m super(2)/d. The low end of this range is similar to fluxes from Canadian Shield lakes and the ocean; the high end is 500 x higher. Fluxes from the HBL ponds (0.4 - 4  mu mol S/m super(2)/d) were similar to fluxes from Canadian Shield lakes.
AN: 3580947

                                                                    588 of 1521  
TI: Cycling and accumulation of biogenic silica and organic matter in high-latitude environments: The Ross Sea
AU: DeMaster,-D.J.; Dunbar,-R.B.; Gordon,-L.I.; Leventer,-A.R.; Morrison,-J.M.; Nelson,-D.M.; Nittrouer,-C.A.; Smith,-W.O.,Jr.
AF: Dep. Mar., Earth., Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695-8208, USA
SO: OCEANOGRAPHY 1992 vol. 5, no. 3, pp. 146-153
LA: English
ER: M (Marine)
AB: The focus of this high-latitude study has been to quantify the cycles of Si and organic C in the water column and seabed and to identify the primary location of the fractionation between fluxes of biogenic silica and organic matter. Measurements of uptake and regeneration rates were made for organic and siliceous phases throughout the upper 150 m of the water column. Particle traps were used to characterize changes in the nature of the biogenic particles within the water column at depths of 231 and 500-750 m below the ocean surface. Box cores and kasten cores were collected from the seabed to evaluate regeneration of biogenic phases below the sediment-water interface as well as accumulation rates of biogenic material in the sediment column. The Ross Sea was chosen because it typifies many Antarctic settings and is characterized by significant biogenic production and seabed accumulation, relatively confined boundaries, water circulation that is reasonably well understood (as compared with the complex dynamics of the Polar Front), and close proximity to a major Antarctic support facility (McMurdo Station). A two-year time-series study has been conducted in an effort to minimize potential biases from short-term blooms and episodic changes in circulation and sedimentation. This paper describes several unique aspects of nutrient and carbon cycling in the high-latitude environment of the Ross Sea.
AN: 3580339

                                                                    589 of 1521  
TI: Physiological limitations on phytoplankton productivity in the ocean
AU: Falkowski,-P.G.; Greene,-R.M.; Geider,-R.J.
AF: Oceanogr. Atmos. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: OCEANOGRAPHY 1992 vol. 5, no. 2, pp. 84-91
LA: English
ER: M (Marine)
AB: The question of what limits primary productivity and phytoplankton biomass in natural waters has occupied oceanographers and limnologists for more than a century. The earliest oceanographers recognized that this issue is key to understanding the regulation of both aquatic food chains and biogeochemical cycles. Traditionally, phytoplankton ecologists have been imbued with the concepts of the light, nitrogen and temperature limitation as they relate to the critical depth model, Michaelis-Menten kinetics, and thermodynamic constraints on growth. The recent suggestion that a micronutrient, such as iron, limits phytoplankton biomass or production in vast portions of the world's oceans has been met with some skepticism. To a large extent the difficulty in determining what limits primary production stems both from methodological deficiencies and semantic confusion. The identification of limiting factors has been based on primarily three techniques: correlative inference, experimental manipulation, and simulation modeling. Here we examine the concepts of limiting factors and explore the possibility of using in vivo chlorophyll fluorescence (a biophysical signal), in conjunction with molecular markers, to identify or diagnose factors limiting phytoplankton growth and production in the ocean.
AN: 3580332

                                                                    590 of 1521  
TI: Measurement of dissolved organic carbon and nitrogen in natural waters
AU: Williams,-P.M.
AF: Mar. Res. Div., Scripps Inst. Oceanogr., Univ. Califonia, La Jolla, CA 92093-0218, USA
SO: OCEANOGRAPHY 1992 vol. 5, no. 2, pp. 107-116
LA: English
ER: M (Marine)
AB: The potential impact of elevated dissolved organic carbon (DOC) and nitrogen (DON) concentrations on the biogeochemical cycling of organic matter in the oceans is profound. Yet we are at an impasse in obtaining accurate measurements of DOC and DON. A Workshop in Seattle (15-19 July 1991) was conceived to bring order to the present uncertainties in these measurements and to make explicit recommendations for future analytical protocols and experimentation.
AN: 3580219

                                                                    591 of 1521  
TI: Marine calcification as a source of carbon dioxide: Positive feedback of increasing atmospheric CO sub(2)
AU: Frankignoulle,-M.; Canon,-C.; Gattuso,-J.-P.
AF: Univ. Liege, Lab. Oceanol., Inst. Chim., Bat B6, B 4000 Sart Tilman, Belgium
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 2, pp. 458-462
LA: English
ER: M (Marine)
AB: Calcification is a well-recognized source of CO sub(2) to the surrounding water and thus a potential source of atmospheric CO sub(2) due to chemical equilibria involving the CO sub(2) species. The released CO sub(2): precipitated carbonate ratio ( psi ) has recently been estimated to be 0.6 in seawater (taking into account the buffering capacity of the latter). We report an analytical expression enabling the computation of this ratio. Calculations show that the amount of CO sub(2) that must be released to equilibrate seawater increases with increasing partial pressure of CO sub(2) in seawater (pCO sub(2)), which results from human impact on atmospheric CO sub(2). We show that at 15 degree C  psi  increased from 0.55 during the time of glaciation to 0.67 at present and would increase to 0.84 for a pCO sub(2) of 1,000  mu atm. Doubling the preindustrial pCO sub(2) value results in a total CO sub(2) source of  similar to 5 Gt C (taking into account the described buffering effect).
AN: 3580070

                                                                    592 of 1521  
TI: Metal accumulation within salt marsh environments: A review
AU: Williams,-T.P.; Bubb,-J.M.; Lester,-J.N.
AF: Environ. and Water Resour. Eng. Section, Civ. Eng. Dep., Imperial Coll. Sci., Technol. and Med., London SW7 2BU, UK
SO: MAR.-POLLUT.-BULL. 1994 vol. 28, no. 5, pp. 277-290
LA: English
ER: M (Marine); B (Brackish)
AB: A comprehensive assessment of the chemical and physical factors affecting metal accumulation and cycling within salt marshes is presented. The effects that changes in physico-chemical properties (redox potential, salinity, pH, etc.) have upon metal mobility, speciation and consequent biological availability are described together with the implications for salt marsh habitat loss. Salt marshes act as very efficient sinks for metal contaminants although metal concentrations in halophytes do not generally reflect environmental contamination levels. Marine angiosperms, particularly Zostera marina, do however, reflect external metal concentrations and can therefore be used as biomonitors. Evidence suggests that the concentration of heavy metals in the sediments of most estuaries is not sufficiently high to cause ill effects to salt marsh plants although further investigations are necessary to assess potential threats of pollutants upon the health of these intertidal ecosystems.
AN: 3579535

                                                                    593 of 1521  
TI: Partitioning of Cu in estuarine waters, 1. Partitioning in a poisoned system
AU: Paulson,-A.J.; Curl,-H.C.,Jr.; Gendron,-J.F.
AF: Spokane Res. Cent., U.S. Bur. Mines, E. 315 Montgomery Ave., Spokane, WA 99207, USA
SO: MAR.-CHEM. 1994 vol. 45, no. 1-2, pp. 67-80
LA: English
ER: M (Marine)
AB: The importance of dissolved hydrophobic organic matter in controlling the partitioning of Cu between the dissolved and particulate phases in natural waters was determined. Estuarine particulate matter was suspended in two solutions: (1) filtered seawater, and (2) filtered seawater in which the hydrophobic organic matter had been removed. Radioactive Cu was then added to each suspension. The removal of hydrophobic dissolved organic matter resulted in a two-fold increase in the distribution coefficient (K sub(D)) of added radioactive Cu (from 10 super(4.50) to 10 super(4,81) l/kg). The partitioning of  super(64)Cu in the suspensions was controlled by chemical processes dominated by complexation with particulate and dissolved organic matter.
AN: 3579501

                                                                    594 of 1521  
TI: SeaWiFS technical report series. Volume 1: An overview of SeaWiFS and ocean color
AU: Hooker,-S.B.; Firestone,-E.R.; Esaias,-W.E.; Feldman,-G.C.; Gregg,-W.W.
CA: National Aeronautics and Space Adm., Greenbelt, MD (USA). Goddard Space Flight Cent.
SO: 1992 28 pp
RN: NAS 1.15:104566-V-1, NASA-TM-104566-V-1 (115104566V1NASATM104566V1)
LA: English
ER: M (Marine)
AB: The purpose of this series of technical reports is to provide current documentation of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project activities, instrument performance, algorithms, and operations. This documentation is necessary to ensure that critical information related to the quality and calibration of the satellite data is available to the scientific community. SeaWiFS will bring to the ocean community a welcomed and improved renewal of the ocean color remote sensing capability lost when the Nimbus-7 Coastal Zone Color Scanner (CZCS) ceased operating in 1986. The goal of SeaWiFS, scheduled to be launched in August 1993, is to examine oceanic factors that affect global change. Because of the role of phytoplankton in the global carbon cycle, data obtained from SeaWiFS will be used to assess the ocean's role in this cycle, as well as other biogeochemical cycles. SeaWiFS data will be used to help elucidate the magnitude and variability of the annual cycle of primary production by marine phytoplankton and to determine the distribution and timing of spring blooms. The observations will help to visualize the dynamics of ocean and costal currents, the physics of mixing, and the relationships between ocean physics and large-scale patterns of productivity. The data will help fill the gap in ocean biological observations between those of the CZCS and the upcoming Moderate Resolution Imaging Spectrometer (MODIS) on the Earth Observing System-A (EOS-A) satellite.
AN: 3578864

                                                                    595 of 1521  
TI: Chemical fluxes and mass balances in a marine fish cage farm. 3. Silicon
AU: Holby,-O.; Hall,-P.O.J.
AF: Dep. Anal. and Mar. Chem., Univ. Goeteborg, S-412 96 Goeteborg, Sweden
SO: AQUACULTURE 1994 vol. 120, no. 3-4, pp. 305-318
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Fluxes and pathways of silicon in a marine rainbow trout (Oncorhynchus mykiss) cage farm were studied. The measured fluxes included those carried by fish food, juveniles, harvest, fish loss (death and escape), sedimentation from the cages, and benthic release measured with flux chambers in-situ. Two different types of Si mass balances for the farm were constructed. The mass balance according to the flux method was based on the measured fluxes and constructed for each of two consecutive growing seasons. The mass balance constructed according to the accumulation method was based on the total input and removal of Si to the cages of the farm since it was started, and the recovery of Si in the sediment originating from the farm. In both types of mass balances external input was the major source of Si, contributing a minimum of 55-80% of the total biogenic silica in the material collected in sediment traps below the farm and of the material accumulated in the farm-derived sediment. The Si removed from the farm with harvest contributed a very small part,  similar to 0.3%, of the amount of Si supplied to the farm with fish food and juveniles. The loss of Si to the environment was 2.4 kg (1985), 2.5 kg (1986) and 2.5 kg (1980-86) for each ton of fish produced. On a seasonal basis, about 4.5% of the sedimented biogenic Si was returned in dissolved form from the sediment to the overlying water. This constituted about 0.3% of the biogenic Si content in the farm-derived sediment. The flux of reactive silicate from sediment below the fish farm was enhanced about 2.5 times compared to nearby sediments unaffected by the farm.
AN: 3578471

                                                                    596 of 1521  
TI: Comparison of the August-September 1991 and 1979 surface partial pressure of CO sub(2) distribution in the Equatorial Pacific Ocean near 150 degree W
AU: Goyet,-C.; Peltzer,-E.T.
AF: Woods Hole Oceanogr. Inst., Dep. Mar. Chem. and Geochem., Woods Hole, MA 02543, USA
SO: MAR.-CHEM. 1994 vol. 45, no. 4, pp. 257-266
LA: English
ER: M (Marine)
AB: The partial pressure of CO sub(2) (pCO sub(2)) in the surface seawater and marine air from 17 degree S to 22 degree N near 151 degree W (WOCE leg P-16c) during the period from August 31 to September 29, 1991, were measured continually. The surface seawater pCO sub(2) showed large latitudinal variation with a maximum of 425  mu atm near the equator. These results are compared with pCO sub(2) measurements in 1979, in the same area and same months. The short-scale (temporal and spatial) variations in surface seawater pCO sub(2) ( plus or minus 6.1  mu atm) do not allow us to unequivocally quantify the variation in  Delta pCO sub(2) (pCO sub(2) super(sea)-pCO sub(2) super(air)) between the years 1979 and 1991 due to oceanic uptake of fossil fuel CO sub(2). However, the data suggest that this ocean area might be a stronger source of CO sub(2) for the atmosphere than may be expected from results of ocean models.
AN: 3573487

                                                                    597 of 1521  
TI: Iron oxidation kinetics in an acidic alpine lake
AU: Barry,-R.C.; Schnoor,-J.L.*; Sulzberger,-B.; Sigg,-L.; Stumm,-W.
AF: Dep. Civ. Environ. Eng., Univ. Iowa, Iowa City, IA 52242, USA
SO: WATER-RES. 1994 vol. 28, no. 2, pp. 323-333
LA: English
ER: F (Freshwater)
AB: Four experiments were performed to assess the role of homogeneous, heterogeneous, biological and photochemical processes in the oxygenation of ferrous iron in aquatic ecosystems. Experiments were carried out at Lake Cristallina, Ticino, Switzerland, and in the laboratory. Rate constants are presented for homogeneous oxygenation in lakewater, for oxygenation by lake sediment under sterile and non-sterile conditions and for heterogeneous oxygenation in the presence of TiO sub(2), MnO sub(2), Fe sub(2)O sub(3), Al sub(2)O sub(3) and SiO sub(2). It was found that, on a surface area adjusted basis, TiO sub(2), MnO sub(2) and Fe sub(2)O sub(3) were three orders of magnitude more effective in accelerating oxygenation than Al sub(2)O sub(3) and SiO sub(2), suggesting that these minerals form strong, inner sphere complexes with Fe(II) in the pH range 4-6. Sterilization by gamma irradiation reduced oxygenation rate in the presence of lake sediment by two orders of magnitude on a surface area adjusted basis. Oxygenation in the presence of 0.44  mu m filtered lakewater was not appreciably different from that in distilled water. In situ experiments showed that oxygenation rate increased in the presence of sunlight. The heterogeneous rate constant for iron oxidation with lake sediment was 4.9 x 10 super(14)/M super(2)/atm/s/m super(2) and with pure minerals ranged from 1.8 x 10 super(10) to 5.3 x 10 super(13)/M super(2)/atm/s/m super(2).
AN: 3571436

                                                                    598 of 1521  
TI: Response of a coupled ocean-atmosphere model to increasing atmospheric carbon dioxide
AU: Manabe,-S.; Stouffer,-R.J.; Spelman,-M.J.
AF: Geophys. Fluid Dyn. Lab./NOAA, Princeton Univ., P.O. Box 308, Princeton, NJ 08542, USA
SO: AMBIO 1994 vol. 23, no. 1, pp. 44-49
LA: English
ER: M (Marine)
AB: This study investigates the response of a climate model to a 1% per year increase of atmospheric carbon dioxide. The model is a general circulation model of the coupled ocean-atmosphere-land surface system, with a global computational domain, smoothed geography, and seasonal variation of insolation. The simulated increase of sea-surface temperature is very slow in the northern North Atlantic and the Circumpolar Ocean of the Southern Hemisphere where the vertical mixing of water penetrates very deeply and the rate of deep water formation is relatively fast. Extending this work, we investigated the transient responses of the coupled model to the doubling and quadrupling of atmospheric CO sub(2), over the period of several centuries. During the entire 500-yr period of the experiment, the global mean surface air temperature increases almost 3.5 degree C when CO sub(2) is doubled, and 7 degree C when it is quadrupled. In the latter experiment, the thermal structure and dynamics of the model oceans undergo drastic changes, such as cessation of the thermohaline circulation in most of the model oceans, and substantial deepening of the thermocline, especially in the North Atlantic. These changes prevent the ventilation of the deeper layer of the oceans and, if they occurred in reality, could have a profound impact on the carbon cycle and biogeochemistry of the coupled ocean-atmosphere system.
AN: 3571406

                                                                    599 of 1521  
TI: Planetary metabolism: Understanding the carbon cycle
AU: Moore,-B.,III; Braswell,-B.H.,Jr.
AF: Inst. Study Earth, Oceans, and Space, Univ. New Hampshire, Morse Hall, Durham, NH 03824-3525, USA
SO: AMBIO 1994 vol. 23, no. 1, pp. 4-12
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Biological systems are intimately involved in the transfers of energy and materials around our planet, affecting the geochemistry and other physical properties of the atmosphere, the land surface, and the oceans and their sediments. Fossil-fuel combustion, land use and other human activities are, increasingly, disrupting these natural biogeochemical cycles and processes, with the potential for far-reaching consequences; for example, changes in atmospheric composition affecting the global heat balance. The carbon, nitrogen and sulfur cycles are of particular importance to the functioning of the biosphere, and are also closely linked to the physical climate system. Within IGBP, the global-scale modelling effort is initially focussed on the carbon cycle: this is poorly understood-yet is critical to estimating future levels of CO sub(2) and other greenhouse gases, and their direct and indirect interactions with the biosphere. To assist in determining the factors that influence the atmospheric lifetime of CO sub(2), the concept of a single half-life (T sub(1/2)) is applied to three simple ocean carbon-cycle models and a model of global terrestrial carbon cycling. We find significant differences due to the inclusion of the terrestrial model and the nature of the assumptions made about the possible terrestrial fertilization response: estimates of T sub(1/2) vary between 92 years (no allowance for terrestrial effects) to 27 years (with both terrestrial regrowth plus fertilization). The range of these values raises further scientific questions, and has implications for policy development.
AN: 3571405

                                                                    600 of 1521  
TI: Degradation processes of phytoplankton in a eutrophic bay with particular reference to the chlorophyll a pigment composition of suspended and sinking particles.
OT: Kaisuichu-kendakurushi to chikoryushi no kurorofiru-a-rui sosei kara mita fueiyo-naiwan ni okeru shokubutsu purankuton no bunkai katei
AU: Sakoh,-H.; Matsuda,-O.; Yamamoto,-T.
AF: Fac. Appl. Biol. Sci., Hiroshima Univ., Higashi-Hiroshima, 724 Japan
SO: J.-FAC.-APPL.-BIOL.-SCI.-HIROSHIMA-UNIV.-HIRODAI-SEIBUTSUSEISANGAKUBU-KIYO 1993 vol. 32, no. 2, pp. 79-86
LA: Japanese
ER: M (Marine)
AB: Physiological condition of phytoplankton can be estimated from both quantitative and qualitative analyses of photosynthetic pigments. In this study, the process of chlorophyll a degradation in an enclosed eutrophic bay were investigated using high-performance liquid chromatography (HPLC). Chlorophyll a and its derivatives were classified into chl.a, chl.a isomers (chl.a'-1, 2, 3) and pheopigments by the use of reverse-phased HPLC. Resulted pigment compositions were compared between suspended particles, sinking particles and surface sediment in Etauchi Bay. Chl.a was more abundant in suspended particles than in sinking particles, while pheopigments in both particles accounted for only less than 30%.
AN: 3570441

                                                                    601 of 1521  
TI: Rapid cycling of high-molecular-weight dissolved organic matter in the ocean
AU: Amon,-R.M.W.; Benner,-R.
AF: Mar. Sci. Inst., Univ. Texas at Austin, Port Aransas, TX 78373-1267, USA
SO: NATURE 1994 vol. 369, no. 6481, pp. 549-552
LA: English
ER: M (Marine)
AB: Dissolved organic matter (DOM) in the ocean is one of the largest active reservoirs of organic carbon on Earth. It is important to understand the processes by which DOM is recycled, particularly as changes in the oceanic DOM pool could affect atmospheric carbon dioxide concentrations on timescales of 1,000 to 10,000 years. It is commonly believed that low-molecular-weight material, which comprises 65-80% of DOM, is rapidly remineralized, and that high-molecular-weight material is refractory. But the average age of DOM in the deep ocean is about 6,000 years which implies that a large proportion of the DOM cycles only very slowly. Here we present a study of the relative bioavailability of low- and high-molecular weight DOM in water samples taken from the northern Gulf of Mexico during a diatom bloom. Bacterial growth and respiration in the presence of high-molecular-weight DOM were respectively three and six times greater than for low-molecular-weight material. Although both of these pools undoubtedly contain mixtures of compounds with varying reactivities and turnover times, our results demonstrate that the bulk of oceanic DOM comprises small molecules that cycle slowly and are relatively unavailable to microorganisms.
AN: 3569238

                                                                    602 of 1521  
TI: Stable isotopic structure of aquatic ecosystems
AU: Wada,-E.; Kabaya,-Y.; Kurihara,-Y.
AF: Cent. Ecol. Res., Kyoto Univ., 4-1-23 Shimosakamoto, Otsu, Shiga 520-01, Japan
SO: J.-BIOSCI. 1993 vol. 18, no. 4, pp. 483-499
LA: English
ER: B (Brackish)
AB: Isotopic, biogeochemical and ecological structure can provide a new dimension for understanding material flows, and the simultaneous function and structure of an ecosystem. Distributions of  delta  super(13)C and  delta  super(15)N for biogenic substances in the Nanakita River estuary involving Gamo lagoon in Japan were investigated to construct isotope biogeochemical and ecological structure for assessing fate and transfer of organic matter, and food web structure. The isotopic framework of the ecosystem was successfully described in a  delta  super(15)N- delta  super(13)C map. In this estuary the variations of isotope ratios of biogenic substances were clearly explained by the mixing of land-derived organic matter, and marine-derived organic matter. A trophic-level effect of  super(15)N enrichment was clearly observed. Organisms were classified into three groups depending upon the contribution of land-derived organic matter in a food chain. Almost all biota except mollusca in the lagoon depend on organic matter of marine origin. The contributions of both land and marine organic matter were comparable for mollusca in the lagoon.
AN: 3569192

                                                                    603 of 1521  
TI: Chlorophyll, photosynthesis and new production in the Southern California Bight
AU: Eppley,-R.W.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093-0218, USA
SO: PROG.-OCEANOGR. 1992 vol. 30, no. 1-4, pp. 117-150
LA: English
ER: M (Marine)
AB: The study of phytoplankton distributions and processes in these waters has been stimulated in recent years by the synoptic views of surface pigment afforded by the Coastal Zone Color Scanner (CZCS) aboard the NIMBUS-7 satellite; by rapid developments in bio-optical oceanography toward the estimation of in sity photosynthetic rate; by use of sediment traps and geochemical tracers to determine the flux of organic matter from the euphotic zone; and by measurements of new production based on the utilization of nitrate by the plankton. The evolution and rationale of the Joint Global Ocean Flux Study of ocean biogeochemical cycles and ocean climate change serve to focus much of the work. In that context, a major goal is to assess new/export production on large time and space scales accessible to date only by remote sensing.
AN: 3569123

                                                                    604 of 1521  
TI: Biodegradable substances in lake sediments and their relation to sediment microbiological activity and phosphorus recycling
AU: Matinvesi,-J.; Heinonen-Tanski,-H.
AF: Natl. Board Waters and Environ., Dist. Off. Kuopio, Box 49 SF-70101 Kuopio, Finland
SO: AQUA-FENN. 1992 vol. 22, no. 2, pp. 193-200
LA: English
ER: F (Freshwater)
AB: Phosphorus recycling from lake sediments is a complex process, that depends, on physical chemical, and microbiological conditions. The authors measured ignition loss, BOD sub(7) tot-N, tot-P, tot-Fe, and some microbiological parameters in lake sediment samples. There is a good correlation between the number of bacteria, phosphatase enzyme activities, and the amount of BOD sub(7) in top sediments. Top sediment profiles were taken from the deepest part of six central Finnish lakes representing six different trophic states, and each profile was divided into three layers. The phosphatase enzyme activity, the number of acetic-acid-, ferric-phosphate-, and tricalcium-phosphate-utilizing bacteria, and the levels of organic substances were highest in the top layer of every sediment profile. Organic phosphatase enzyme activity levels were 10 to 25 times higher than inorganic phosphatase enzyme activity levels in the top sediment subsamples. The amount of BOD sub(7) in the top layer of the sediment correlated to the amount of total phosphorus in the very top layer (0-1.5 cm). Microbiological phosphate mineralization from organic substances may be the main reason for the inner load of phosphorus in the lakes of central Finland.
AN: 3568643

                                                                    605 of 1521  
TI: Biogeochemical cycling in the northwestern Indian Ocean: A brief overview
AU: Burkill,-P.H.; Mantoura,-R.F.C.; Owens,-N.J.P.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth PL1 3DH, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 643-649
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The northwestern Indian Ocean may be defined conveniently as the ocean basin that is bounded by the African and Asian land masses to the west and north, and the Indian subcontinent and the Maldives to the east. With a southern boundary chosen arbitrarily as the Equator, its area is about 6.2 x 10 super(6) km super(2). Although it is one of the smallest ocean basins, it contains a diversity of biogeochemical provinces such as eutrophic, oligotrophic, upwelling and reduced oxygen environments. The presence of such diversity within a small ocean basin has made it an attractive location for biogeochemical studies. Many of these have been reviewed. In this issue, we report the results of more recent biogeochemical studies carried out abroad R.R.S. Charles Darwin, R.V. Meteor and O.R.V. Sagar Kanya during 1986-88.
AN: 3567041

                                                                    606 of 1521  
TI: Nitrogen biogeochemical cycling in the northwestern Indian Ocean
AU: Mantoura,-R.F.C.; Law,-C.S.; Owens,-N.J.P.; Burkill,-P.H.; Woodward,-E.M.S.; Howland,-R.J.M.; Llewellyn,-C.A.
AF: Plymouth Mar. Lab., Prospect Pl., West Hoe, Plymouth, PL1 3DH, Devon, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 651-671
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The vertical distribution and fine scale structure of nitrate (NO sub(3)), nitrite (NO sub(2)), nitrous oxide (N sub(2)O), phosphate (PO sub(4)), oxygen (O sub(2)) and chlorophyll a (chl a) were determined in the North Western Indian Ocean (NWIO) along a meridional section (67 degree E) from the Equator to the Gulf of Oman using an Autoanalyser for micromolar levels of nutrients, and chemiluminescence and gas chromatographic methods for nanomolar levels of NO sub(3) and NO sub(2) and N sub(2)O respectively. Three biogeochemically contrasting regimes were investigated: (1) the highly oligotrophic nutrient-depleted subtropical gyre; (2) the monsoonal upwelling of nutrient-rich intermediate waters off the southeastern Arabian Coast; and (3) the denitrifying O sub(2)-depleted zone (ODZ; ca 150-1200 m depth) in the Arabian Sea.
AN: 3567040

                                                                    607 of 1521  
TI: Maintenance of the low-oxygen layer in the central Arabian Sea
AU: Olson,-D.B.; Hitchcock,-G.L.; Fine,-R.A.; Warren,-B.A.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 673-685
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: An intermediate depth layer, approximately 1 km thick, in the northwestern Indian Ocean contains essentially no detectable dissolved oxygen. Previous suggestions for primary causes of this feature have been: (a) very slow movement within the layer, allowing a long time for organic decomposition to consume the oxygen; (b) very large local consumption rates, resulting from enormous productivity in the surface layer; or (c) low oxygen concentrations in the waters entering the layer from the south, due to their long transit from their sea-surface sources. Observations reported here of a transient anthropogenic trace gas, trichlorofluoromethane (F-11 or freon 11), however, demonstrate that the residence time for water in the low-oxygen layer is not especially long, about 10 years. Concurrent summertime measurements of surface productivity, while high, preclude an exceptional mean consumption rate at depth. An oxygen budget for the layer supports the idea that the near-zero concentration is maintained by moderate consumption applied to waters with initially low oxygen concentration that pass through the layer at moderate speed.
AN: 3567039

                                                                    608 of 1521  
TI: Activity of the respiratory electron transport system and respiration rates within the oxygen minimum layer of the Arabian Sea
AU: Naqvi,-S.W.A.; Shailaja,-M.S.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 687-695
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Measurements of the activity of the respiratory electron transport system (ETS) at 15 stations in the Arabian Sea during the northeast monsoon (December 1988) yield high respiration rates that do not correlate with the trends in primary productivity. The rates are unlikely to be sustained by the supply of carbon associated with the sinking particles alone, and seem to suggest a major role for dissolved and/or suspended organic matter in fuelling oxygen consumption and denitrification. The data are utilized to compute a denitrification rate of 24-33 Tg N y super(-1) in the Arabian Sea. This estimate agrees with the estimate based on the exports of nitrate deficits outside the denitrification zone. The ventilation time of the denitrifying layer is calculated as  similar to 1 year.
AN: 3567038

                                                                    609 of 1521  
TI: Size-fractionated primary production and nitrogen assimilation in the northwestern Indian Ocean
AU: Owens,-N.J.P.; Burkill,-P.H.; Mantoura,-R.F.C.; Woodward,-E.M.S.; Bellan,-I.E.; Aiken,-J.; et-al.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth, PL1 3DH, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 697-709
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Rates of phytoplankton production and nitrogen assimilation were measured at various stations along a transect in the northwestern Indian Ocean, from near the equator, northwards into the upwelling system off the Arabian peninsula, during September-October 1986. The measurements were made using in situ incubation techniques with the simultaneous use of  super(14)C and  super(15)N isotopes. Samples were fractionated after the incubations into three size classes: 0.2-0.8  mu m, 0.8-5.0  mu m, and >5.0  mu m for the  super(14)C incubations; and <5.0  mu m and >5.0  mu m for the  super(15)N incubations. The assimilation of nitrate and ammonium was measured. These measurements were supported by a detailed description of the horizontal and vertical distributions of chlorophyll, temperature and underwater light field, by the deployment of a towed undulating oceanographic recorder. Rates of primary production ranged from approximately 0.5 g C m super(-2)day super(-1) at the equator, reducing to <0.3 in the oligotrophic gyre in the central northern Indian Ocean, and to >2.5 in the upwelling region off the coast of Oman; total nitrogen assimilation followed a similar pattern. Very significant variations in the size distribution of the activity of the plankton were observed. Over 75% of the carbon and nitrogen assimilation was in the <5  mu m fraction at the south of the transect; this decreased to approximately 10% in the upwelling region. New production (f ratios) varied between approximately 0.1 in the oligotrophic regions and 0.9 in the upwelling region.
AN: 3567037

                                                                    610 of 1521  
TI: Productivity regime and phytoplankton size structure in the Arabian Sea
AU: Jochem,-F.J.; Pollehne,-F.; Zeitzschel,-B.
AF: Inst. Meereskd. Univ. Kiel, Duesternbrooker Weg 20, 2300 Kiel, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 711-735
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The productivity regime and size structure of phytoplankton are described for three different epipelagic systems in the Arabian Sea during the inter-monsoon period in spring 1987: (1) the coast of Oman; (2) the central Arabian Sea; and (3) the shelf off Pakistan. These results are related to the functioning of the specific ecosystem. Off the coast of Oman, the transition from a surface maximum of autotrophic biomass and production to a more oligotrophic system, with a chlorophyll subsurface maximum, was observed. Concomitantly, the size spectrum changed towards a higher significance of picoplankton. In the central Arabian Sea, a typical oligotrophic system with a pronounced subsurface maximum of autotrophic biomass and primary production was encountered. Here, the epipelagic system could be divided into two distinct sub-systems: the surface layer "regenerated" production, the predominance of picophytoplankton and minor losses due to sedimentation, thus a "closed" system; and the subsurface maximum layer at the nutricline characterized by higher sedimentation losses and more diatoms. Both sub-systems showed about the same productivity, the turnover in the surface layer having been much greater than in the subsurface maximum. The system on the shelf off Pakistan is seen as a decay stage of the open ocean system when water from offshore is transported onto the shelf during the onset of monsoon winds.
AN: 3567036

                                                                    611 of 1521  
TI: Low light adaptation and export production in the deep chlorophyll maximum layer in the northern Indian Ocean
AU: Pollehne,-F.; Klein,-B.; Zeitzschel,-B.
AF: Inst. Ostseeforsch., Seest. 15, O-2530 Rostock-Warnemunde, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 737-752
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Phytoplankton standing stock and primary production rates were measured in the central northern Indian Ocean at 65 degree E and 18 degree N in the inter-monsoon period in May 1987. As the algal populations were dominated by minute forms difficult to assess by routine microscopic methods, main algal groups were identified by pigment patterns derived from HPLC-analysis. The main ecological significance of the deep chlorophyll maximum layer at that time was its role as a source of export production while importing "new" nutrients from below the nitracline. HPLC and elemental analyses of sediment trap material proved this layer to be the source of most of the sedimenting particles. Calculations of nitrogen fluxes suggested the import and export terms to be well balanced.
AN: 3567035

                                                                    612 of 1521  
TI: Bacterioplankton distributions and production in the northwestern Indian Ocean and Gulf of Oman, September 1986
AU: Ducklow,-H.W.
AF: Horn Point Environ. Lab., Univ. Maryland CEES, Box 775, Cambridge, MD 21613, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 753-771
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Bacterial abundance and  super(3)H-thymidine incorporation were measured throughout the water column during September-October 1986, along transects in the north western Arabian Sea and Gulf of Oman. Bacterial abundances and production estimated from incorporation rates were high (>1 x 10 super(9) cells/l and 30-92% of primary production, respectively) along the oceanic portions of the transects. These elevated levels may indicate a response to the decline of summer phytoplankton blooms stimulated by monsoonal deepen of the mixed layer. Bacterial production and abundance profiles had complex vertical structure with multiple subsurface maxima related to chlorophyll and oxygen distributions. Production and abundance both declined exponentially with depth below 100-200 m. Rates of dissolved organic carbon (DOC) release from the sinking particle flux may have been adequate to support bacterial production in the Gulf of Oman, but in the open Arabian Sea this source appeared to be insufficient to meet the bacterial demand. The bacterial production estimates reported herein are very conservative because very low conversion factors were used. In general these results suggest that the carbon sources usually assumed to support bacterial production (e.g., phytoplankton exudation, particle breakdown) supply only a fraction of the bacterial demand in the northwest Indian Ocean.
AN: 3567033

                                                                    613 of 1521  
TI: Synechococcus and its importance to the microbial foodweb of the northwestern Indian Ocean
AU: Burkill,-P.H.; Leakey,-R.J.G.; Owens,-N.J.P.; Mantoura,-R.F.C.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth PL1 3DH, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 773-782
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The abundance, distribution, size, biomass, growth and grazing-induced mortality of phycoerythrin (PE) rich chrococcoid cyanobacteria were studied during September-October 1986 in the Arabian Sea, the Gulf of Oman and the monsoonal upwelling region off the South East Arabian coast. Cyanobacteria were abundant through the region and particularly so in oligotrophic waters where they exhibited distinct subsurface concentration maxima that were situated above, but related to the depth of the chlorophyll maxima. Cell diameter increased from 0.7  mu m in surface waters to 1.2  mu m at depth. Standing stocks of cyanobacteria ranged up to 50  mu gC/l, and accounted for up to 40% of the POC in oligotrophic stations indicating that Synechococcus constitutes an important trophic resource. Experimental investigations showed that cyanobacterial populations were growing fast, with specific growth rates of 0.5-1.0/day, while simultaneously experiencing high mortality due to microzooplankton grazing. Grazing rates varied between 0.3 and 1.2/day, indicating that 31-71% of the cyanobacteria were predated daily. Grazing and cyanobacterial growth were correlated, suggesting that Synechococcus production and its fate by microbial grazing activity were tightly coupled. Cyanobacteria are clearly a major component of a dynamic but well-balanced microbial foodweb present in oligotrophic regions of the northwest Indian Ocean.
AN: 3567032

                                                                    614 of 1521  
TI: Effects of forest management on biogeochemical functions in southern forested wetlands
AU: Walbridge,-M.R.; Lockaby,-B.G.
AF: Dep. Biol., George Mason Univ., Fairfax, VA 22030-4444, USA
SO: WETLANDS 1994 vol. 14, no. 1, pp. 10-17
LA: English
ER: F (Freshwater)
AB: Southern forested wetlands perform two important biogeochemical functions on the landscape: 1) nutrient (N and P) removal from incident surface, subsurface, and ground waters, and 2) export of organic carbon and associated nutrients to aquatic ecosystems downstream. In addition to P sediment deposition, which can range from 1.6 to 36.0 kg/ha/yr P, denitrification of NO sub(3)-N (0.5 to 350 kg/ha/yr) and P adsorption (130 to 199 kg/ha/yr) can be important mechanisms associated with N and P removal, respectively. Biological processes, uptake by plants (15.0 to 51.8 kg/ha/yr for N; 0.2 to 3.8 kg/ha/yr for P) and microorganism absorption (16.2 to 87.0 kg/ha/yr for N; 6.6 to 40.0 kg/ha/yr for P) are also important and are intimately associated with organic matter export. Clearcut harvests (ground-based or aerial), followed by natural regeneration, are the most common silvicultural techniques used in forested floodplains in the South. Ground-based methods have been shown to increase soil bulk density and decrease hydraulic conductivity and redox potential in wetter soils. In addition to the increases in soil temperature and soil wetness that frequently occur following forest harvesting, these added effects may be responsible for the reduced productivity and altered species composition observed following ground-based vs. aerial harvests. Changes in denitrification will be a function of the degree to which harvesting affects soil redox potential, substrate (C) availability, and nitrate production. In theory, denitrification rates should increase following harvesting, but low nitrate availability in acid soils may limit this effect. The effects of harvesting on P adsorption processes in forested wetland soils have not been studied. Reductions in plant uptake and litterfall and changes in species composition following harvesting could alter both nutrient retention/transformation and organic C export functions. On wetter sites, canopy removal may stimulate algal populations, providing a short-term mechanism for conserving geochemical exports. Clearcut harvest systems that minimize alterations in soil hydrology and promote rapid vegetation regrowth should have the least effect on biogeochemical functions in southern forested wetlands.
AN: 3565930

                                                                    615 of 1521  
TI: Effect of the genus Mnemiopsis ctenophore, a recent Black Sea immigrant, on the hydrolytic enzymatic processes of protein and polysaccharide decomposition in sea water.
OT: Vliyanie grebnevika Mnemiopsis - vselentsa Chernogo morya na gidroliticheskie fermentativnye protsessa rasshchepleniya belkov i polisakharidov v morskoj vode
AU: Korneeva,-G.A.; Vedernikov,-V.I.
AF: Inst. Okeanol. RAN, Moscow, Russia
SO: IZV.-RAN-BIOL.-PROC.-ACAD.-SCI.-BIOL. 1994 no. 1, pp. 127-131
LA: Russian
ER: M (Marine)
AB: For the first time it was found experimentally that the hydrolytic enzymatic activities in sea water increased in the presence of the ctenophore. Analysis of the experimental results suggests that the Mnemiopsis ctenophore is an important factor activating the biochemical transformation of organic matter in the aerobic zone of the Black Sea.
AN: 3565638

                                                                    616 of 1521  
TI: Factors affecting respiration in dry pond bottom soils
AU: Boyd,-C.E.; Pippopinyo,-S.
AF: Dep. Fish. and Allied Aquacult., Alabama Agric. Exp. Stn., Auburn Univ., Auburn, AL 36849, USA
SO: AQUACULTURE 1994 vol. 120, no. 3-4, pp. 283-293
LA: English
ER: B (Brackish); F (Freshwater)
AB: The potential influence of drying, liming, tilling, bacterial augmentation, and nitrogen fertilization on respiration of pond bottom soil exposed to air between crops was evaluated in laboratory studies using soil respiration chambers. The optimum soil moisture concentration for respiration was 12-20%, and further drying decreased soil respiration. Soil respiration was greatest at pH 7.5-8.0, and both calcium hydroxide and calcium carbonate were effective in enhancing respiration of acidic soil. Pulverization of soil to eliminate the hard surface crust formed on drying accelerated respiration, thus tilling of pond bottom soils would be expected to increase respiration. Nitrogen fertilization showed some benefit to soil respiration, but there was no value in bacterial augmentation. These laboratory findings provide background information useful to pond studies on bottom soil treatments.
AN: 3564640

                                                                    617 of 1521  
TI: Biodegradation of sucralose, a chlorinated carbohydrate, in samples of natural environments
AU: Labare,-M.P.; Alexander,-M.*
AF: Lab. Soil Microbiol., Dep. Soil, Crop and Atmos. Sci., Cornell Univ., Ithaca, NY 14853, USA
SO: ENVIRON.-TOXICOL.-CHEM. 1993 vol. 12, no. 5, pp. 797-804
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Measurements were made of the biodegradation of 4-chloro-4-deoxy- alpha ,D-galactopyranosyl-1,6-dichloro-1,6- dideoxy- beta ,D-fructofuranoside (sucralose) in samples of several natural environments. This chlorinated carbohydrate, which represents a new class of artificial sweeteners, was extensively transformed to CO sub(2) in four mineral soils with pH values of 4.9 to 7.2. Mineralization occurred at concentrations of 0.01 to 1,000 mg of sucralose per kilogram of soil, and the initial rates were a direct function of substrate concentration. At the lower concentrations, mineralization was initiated with no detectable acclimation period. Mineralization was not evident in soil under anaerobiosis. Mineralization occurred in lake sediments, sewage, and estuarine water but at lower rates and lesser extents than in soils. Little mineralization was evident in samples from oligotrophic, mesotrophic, and eutrophic lakes, the extent of mineralization being often less than the contamination level of the sucralose preparation. Sucralose degradation resulted from microbial activity because mineralization did not occur in sterilized environmental samples, and the addition of cycloheximide or streptomycin to soil significantly reduced mineralization. No bacterium could be isolated that was capable of utilizing sucralose as the sole carbon source. The data suggest that the biodegradation of sucralose is a cometabolic process.
AN: 3560978

                                                                    618 of 1521  
TI: Isotopic signatures ( super(14)C,  super(13)C,  super(15)N) as tracers of sources and cycling of soluble and particulate organic matter in the Santa Monica Basin, California
AU: Williams,-P.M.; Robertson,-K.J.; Soutar,-A.; Griffin,-S.M.; Druffel,-E.R.M.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093, USA
SO: PROG.-OCEANOGR. 1992 vol. 30, no. 1-4, pp. 254-290
LA: English
ER: M (Marine)
AB: Measurements of  Delta  super(14)C,  delta  super(13)C and  delta  super(15)N are reported for dissolved (plus colloidal), suspended and sinking particulate, and total sedimentary organic matter in the Santa Monica Basin (mid-basin and shelf sites) on CaBS cruises 1, 3, 4, 7, 8 and 10. These isotopic signatures were indicative of the following processes occurring within the basin regime: terrestrial inputs of organic matter to the sinking and suspended particulate organic matter were of the order of 10% or less, and as high as 25% for the sedimentary organic matter;  Delta  super(14)C values of the UV-oxidizable dissolved organic matter below 5 m were similar to those measured in open ocean waters, while the  Delta  super(14)C values in the suspended, and, to a lesser degree, in the sinking organic matter decreased markedly with depth. This latter decrease was primarily attributed to episodic resuspension of shelf and slope sedimentary organic matter, and secondarily to natural and/or anthropogenic petroleum inputs; and the isotopic signatures of the UV-oxidizable dissolved organic matter, coupled with total dissolved carbon and amino acid and carbohydrate concentrations were strikingly similar in the deep basin and at an open-ocean site, suggesting a common history for the subsurface (>300 m) and deep water at both sites. In addition, total mass and organic carbon and nitrogen fluxes from five particle trap deployments are described in detail. Mass fluxes increased with depth, especially on the shelf, suggesting that particle input from the basin slopes may reach the mid-basin site. We conclude that there is minimal perturbation of all organic phases in the basin from terrestrial sources, and that the properties of the UV-oxidizable dissolved organic matter are not greatly influenced by particles of local origin.
AN: 3559040

                                                                    619 of 1521  
TI: Upper ocean mixing: The use of algal pigments as biological tracers for turbulent diffusion
AU: Welschmeyer,-N.
CA: Moss Landing Marine Labs., CA (USA)
SO: 1992 4 pp
LA: English
ER: M (Marine)
AB: The goal of the proposed research was to develop an in situ method for determining upper-ocean mixing rates using algal pigments as natural biological tracers. The work focused specifically on xanthophyll-cycling, a well known series of reversible, light-sensitive pigment transformations that occur in all higher land plants and many marine phytoplankton species. Laboratory work was initiated to define the rate constants for xanthophyll-cycling in microalgal cultures, and to develop a quantitative understanding of the influence of light intensity on the xanthophyll-cycling process. Field work was completed which verified that xanthophyll-cycling processes measured in natural phytoplankton populations indeed reproduced our laboratory observations. A Monte-Carlo computer model was developed in order to study the influence of xanthophyll-cycling on algal pigmentation under known conditions of simulated mixing. The collective results from physiological experimentation and simulation modeling were used to develop a field method for calculating ocean mixing rates (Welschmeyer and Hoepffner, 1991; Welschmeyer 1991). The work has now identified previously unrecognized relationships between xanthophyll- cycling and cellular fluorescence, which are of potential importance in exploiting single-cell characteristics as novel tracers of ocean mixing. This new work is continuing in our laboratory.
AN: 3557678

                                                                    620 of 1521  
TI: Biogeochemical interactions in the Equatorial Pacific
AU: Barber,-R.T.; Murray,-J.W.,Jr.; McCarthy,-J.J.
AF: Duke Univ., Sch. Environ., Mar. Lab., 111 Pivers Island Rd., Beaufort, NC 28516-9721, USA
SO: AMBIO 1994 vol. 23, no. 1, pp. 62-66
LA: English
ER: M (Marine)
AB: During 1992, the Joint Global ocean Flux Study (JGOFS) investigated biogeochemical fluxes in the central equatorial Pacific Ocean. The equatorial pacific is the largest natural source of atmospheric carbon dioxide, but the magnitude of the flux varies interannually with the El Nino-Southern Oscillation cycle. Sediments beneath the equatorial upwelling are enriched in organic carbon indicating a strong export flux, but contemporary new primary production is lower than expected given the relative concentrations of new nutrients. The multidisciplinary JGOFS research plan was designed to address apparent contradictions in this system, and to assess the roles of equatorial physical and biological processes in regulating the ocean-atmosphere exchange of carbon.
AN: 3557067

                                                                    621 of 1521  
TI: Nitrogen-15 and oxygen-18 characteristics of nitrous oxide: A global perspective
AU: Kim,-K.-R.; Craig,-H.
AF: Isotope Lab., Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0220, USA
SO: SCIENCE-WASH. 1993 vol. 262, no. 5141, pp. 1855-1857
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The global budget of N sub(2)O shows a significant imbalance between the known rate of destruction in the stratosphere and the estimated rates of natural and anthropogenic production in soils and the ocean. Measurements of the  super(15)N/ super(14)N and  super(18)O/ super(16)O ratios in two major tropospheric sources of N sub(2)O, tropical rain forest soils and fertilized soils, show that soil N sub(2)O from a tropical rain forest in Costa Rica and from sugar-cane fields in Maui is strongly depleted in both  super(15)N and  super(18)O relative to mean tropospheric N sub(2)O. A major source of heavy N sub(2)O, enriched in both  super(15)N and  super(18)O, must therefore be present to balance the light N sub(2)O from soils. One such source is the back-mixing flux of N sub(2)O from the stratosphere, which is enriched in  super(15)N and  super(18)O by photolysis and chemistry. However these return fluxes of  super(15)N and  super(18)O are so great that a large oceanic flux of N sub(2)O is required to balance the heavy isotope-enriched stratospheric flux. All these effects will be reflected in climatically related isotopic variations in trapped N sub(2)O in polar ice cores.
AN: 3556321

                                                                    622 of 1521  
TI: Global nitrogen cycle within the coupled C-N-P system
AU: Lerman,-A.; MacKenzie,-F.T.; Ver,-L.M.
AF: Dep. Geol. Sci., Northwestern Univ., Evanston, IL 60208, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 389-392
LA: English
ER: M (Marine)
AB: The system of C-N-P coupled biogeochemical cycles represents the main interactions between the biosphere and the inorganic world of the planetary surface environment. Within this system, nitrogen occupies a unique position owing to its overwhelmingly large atmospheric reservoir that exceeds by large factors its other major environmental reservoirs, such as the land phytomass, the oceans, and sediments. Our recent version of the global biogeochemical cycle of nitrogen emphasizes three major divisions of the environment: the land part, the coastal margins, and the open oceans. The reservoir masses and the values of some of the more important fluxes are summarized. Features of the nitrogen cycle which are particularly relevant to an understanding of the changing picture of the present-day cycle are discussed.
AN: 3555300

                                                                    623 of 1521  
TI: Sediment-nutrient interactions in tropical seagrass beds: A comparison between a terrigenous and a carbonate sedimentary environment in South Sulawesi (Indonesia)
AU: Erftemeijer,-P.L.A.; Middelburg,-J.J.
AF: Netherlands Inst. Ecol., Cent. Estuar. and Coast. Ecol., Vierst. 28, 4401 EA Yerseke, Netherlands
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 102, no. 1-2, pp. 187-198
LA: English
ER: M (Marine)
AB: The relationship between porewater nutrient concentrations and sediment characteristics was studied in seagrass beds on 2 sediment types in South Sulawesi, Indonesia. Porewater nutrient concentration gradients with sediment depth and ratios between ammonium and phosphate porewater concentrations in a terrigenous muddy sedimentary environment could be explained by modelling based on stoichiometric decomposition of organic material and molecular diffusion. Measured pore-water phosphate concentrations in a carbonate sedimentary environment, however, were significantly higher (10  mu M excess) in the upper few cm of the sediment than would be expected based on stoichiometry. This apparent phosphate enrichment is attributed to rapid regeneration of both N and P in the rhizosphere and subsequent rapid removal of ammonium by nitrification. Sampling artefacts and additional geochemical sources of dissolved P (reduction of hydrous ferric oxides, calcium carbonate dissolution) could be excluded as the cause of the enrichment.
AN: 3554567

                                                                    624 of 1521  
TI: Mineralization of organic nitrogen and carbon (fish food) added to anoxic sediment microcosms: Role of sulphate reduction
AU: Hansen,-L.S.; Holmer,-M.; Blackburn,-T.H.
AF: Dep. Microbial. Ecol., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C., Denmark
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 102, no. 1-2, pp. 199-204
LA: English
ER: M (Marine)
AB: Substrate (fish food) was added to gas-tight bags containing sediment, with and without molybdate. Amino-nitrogen (amino-N) was measured by high-performance liquid chromatography. The oxidation of 3 representative  super(14)C-labelled amino acids (glutamic acid, alanine and arginine) was measured and the mean decay rate constant was used to calculate turnover rates of amino-N. Concentrations of dissolved organic nitrogen, dissolved organic carbon, total organic carbon and ammonium were measured during 28 d of incubation. Inhibition of sulphate-reducing activity gave a 4.2-fold decrease in the rate of ammonium reduction and a 4.5-fold decrease in the rate of amino acid turnover. These results suggest an active participation of sulphate-reducing bacteria in amino acid oxidation.
AN: 3554560

                                                                    625 of 1521  
TI: Multiphasic kinetics can be an artifact of the assumption of saturable kinetics for microorganisms
AU: Logan,-B.E.; Fleury,-R.C.
AF: Dep. Chem. and Environ. Eng., Univ. Arizona, Tucson, AZ 85721, USA
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 102, no. 1-2, pp. 115-124
LA: English
ER: M (Marine)
AB: Much of the evidence for the application of Michaelis-Menten kinetics to bacterial suspensions is derived from Wright-Hobbie plots of radionuclide uptake and incorporation rates in the presence of naturally occurring concentrations of substrates. It is shown that the same data used to support saturation models can also be fitted by a diffusion-based transport equation. Mixed, pure and natural assemblages of microorganisms were used to study glucose uptake and thymidine and leucine incorporation. Multiphasic kinetics for glucose uptake by mixed cultures was observed when data were plotted on a Wright-Hobbie plot (K+S values of 2.7, 37 and 3500  mu M), but the diffusion model fit data with a single set of coefficients over a 6 orders of magnitude range in glucose concentrations. It is suggested that diffusive transport into the cell is dominant at the relatively high thymidine and leucine concentrations used in bacterial production studies, and that non-saturable diffusive transport contributes to widely varying bacterial conversion factors.
AN: 3554476

                                                                    626 of 1521  
TI: Reactivity of aquatic iron(III) oxyhydroxides -- implications for redox cycling of iron in natural waters
AU: Deng,-Yiwei; Stumm,-W.
AF: Dep. Inorg. Chem., R. Inst. Technol., 10044 Stockholm, Sweden
SO: APPL.-GEOCHEM. 1994 vol. 9, no. 1, pp. 23-36
LA: English
AB: The reactivity of iron(III) oxyhydroxides as reflected by their tendency to dissolve is of great importance in the redox cycling of iron and the bioavailability of iron to phytoplankton in natural waters. In this study, various iron(III) oxyhydroxides were produced by oxygenation of iron(II) in the presence of solutes, such as phosphate, sulfate, bicarbonate, valeric acid, TRIS, humic and fulvic acids, and in the presence of minerals, such as bentonite and  delta -Al sub(2)O sub(3) under conditions encountered in aquatic systems. The reactivity of the different iron(III) oxyhydroxides was subsequently assessed by means of a reductive dissolution using ascorbate and non-reductive dissolution using HQS (8-hydroxyquinoline-5-sulfonic acid) or oxalate. The experimental results show that the iron(III) oxyhydroxides with a low degree of polymerization exhibit higher reactivity than those with a high degree of polymerization or with high crystallinity. The quantity of active surface sites and the coordination arrangement of the functional groups at the surface of the iron(III) oxyhydroxides, especially the extent of the endstanding -OH groups per iron(III) ion determine the reactivity of iron(III) oxyhydroxides toward dissolution. Surfaces, such as clay and aluminum oxides, not only accelerate the oxygenation reaction of iron(II), but also induce the formation of iron(III) oxyhydroxides which are more active toward the dissolution reactions. Polymerization of iron(III) oxyhydroxides on the surfaces occurs predominantly in two dimensions rather than in three dimensions. In a laboratory experiment, the iron(III) oxyhydroxide formed in the presence of TRIS can be reduced by fulvic acid in a closed system under the following conditions: Fe(OH) sub(3)(s) 0.01 g/l, fulvic acid 5 mg/l, pH 7.5, 20 degree C. The kinetics of the reaction depend on the reactivity of iron(III) oxyhydroxide and reducing power of fulvic acid. Although reductants other than fulvic acid may be of importance in natural waters, this result provides the laboratory evidence that the >Fe super(III)-OH/Fe(II) is able to act as an electron transfer mediator for the oxidation of natural organic substances, such as fulvic acid, by molecular oxygen either in the absence of microorganisms or as a supplement to microbial activity.
AN: 3553684

                                                                    627 of 1521  
TI: Sulfate reduction and thiosulfate transformations in a cyanobacterial mat during a diel oxygen cycle
AU: Joergensen,-B.B.
AF: Max Planck Inst. Mar. Microbiol., Fahrenheitstr. 1, D-28359 Bremen, FRG
SO: FEMS-MICROBIOL.-ECOL. 1994 vol. 13, no. 4, pp. 303-312
LA: English
ER: M (Marine); B (Brackish)
AB: Bacterial sulfate reduction and transformations of thiosulfate were studied with radiotracers in a Microcoleus chthonoplastes-dominated microbial mat growing in a hypersaline pond at the Red Sea. The study showed how a diel cycle of oxygen evolution affected respiration by sulfate-reducing bacteria and the metabolism of thiosulfate through oxidative and reductive pathways. Sulfate reduction occurred in both oxic and anoxic layers of the mat and varied diurnally, apparently according to temperature rather than to oxygen. Time course experiments showed that the radiotracer method underestimated sulfate reduction in the oxic zone due to rapid reoxidation of the produced sulfide. Extremely high reduction rates of up to 10  mu mol cm super(-3)/d were measured just below the euphotic zone. Although thiosulfate was simultaneously oxidized, reduced and disproportionated by bacteria in all layers of the mat, there was a shift from predominant oxidation in the oxic zone to predominant reduction below. Concurrent disproportionation of thiosulfate to sulfate and sulfide occurred in all zones and was an important pathway of the sulfur cycle in the mat.
AN: 3553681

                                                                    628 of 1521  
TI: Microbial mats in the hypersaline ponds of Mediterranean salterns (Salins-de-Giraud, France)
AU: Caumette,-P.; Matheron,-R.; Raymond,-N.; Relexans,-J.-C.
AF: Lab. Oceanogr. Biol., Univ. Bordeaux I, 2 rue Pr. Jolyet, 33120 Arcachon, France
SO: FEMS-MICROBIOL.-ECOL. 1994 vol. 13, no. 4, pp. 273-286
LA: English
ER: M (Marine); B (Brackish)
AB: Microbial mats that develop in the gypsum crust of the hypersaline ponds of Salins-de-Giraud (Camargue, France) were carefully investigated between 1989 and 1991. During the warm seasons, when these mats were fully developed, analyses of microbial activities and microprofiles of oxygen and sulfide have shown a great activity of the different kinds of bacteria found in the mat below the gypsum crust. Oxygen production could amount to 2  mu mol cm super(-3)/h during the maximum daylight whereas the oxidation of sulfide in the light was calculated to be 12.7  mu mol cm super(-3)/h, i.e. 300 to 180 mmol m super(-2)/day assuming 8-10 hours of constant daylight and a sulfide oxidation zone of 3 mm in thickness. This sulfide oxidation consumes about 65-95% of the diel sulfide production which has been estimated to be 400 to 450 mmol m super(-2)/day originating from sulfate reduction which takes place in the 6 cm depth horizon of sediment plus mat. According to the amounts of sulfate precipitated at the sediment surface in the form of gypsum, sulfate reduction is never limited and was found to be among the highest values reported in the literature (average value of 8200 nmols cm super(-3)/day). Completely covered by the gypsum crust, this ecosystem has been found to react as a closed system. Consequently, the sulfide does not escape and accumulate below the crust. It was detected up to the top of the mat after a few hours of darkness. It is reoxidized during the day by the photosynthetic organisms that form the mats. These latter mats were composed of 2 to 3 laminated layers of phototrophic organisms: an upper brown layer of the cyanobacterium Aphanothece an intermediate green layer of the cyanobacterium Phormidium and an underlying red layer of purple sulfur-oxidizing bacteria from which two new halophilic species were isolated (Chromatium salexigens and Thiocapsa halophila). It has been found that the accumulated sulfide is oxidized not only by the phototrophic bacteria in the sulfide oxidation zone but also by the oxygen produced by the cyanobacteria which are able to photosynthesize in the presence of sulfide.
AN: 3553680

                                                                    629 of 1521  
TI: Biological sinks for nitrogen additions to a forested catchment
AU: Nadelhoffer,-K.J.; Aber,-J.D.; Downs,-M.R.; Fry,-B.; Melillo,-J.M.
CA: Marine Biological Lab., Woods Hole, MA (USA). Ecosystems Cent.
CO: Int. Symp. of Experimental Manipulations of Biota and Biogeochemical Cycling in Ecosystems, Copenhagen (Denmark), May 1992
SO: ECOL.-RES.-SER.-U.S.-ENVIRON.-PROT.-AGENCY 1992 9 pp
RN: EPA/600/A-92/292 (EPA600A92292)
LA: English
ER: F (Freshwater)
AB: The goal of this research is to identify and quantify sinks for experimental Nitrogen (N) additions to a forested catchment at the Bear Brooks Watershed in Maine (BBWM) where background N deposition rates are low (< 4 kg/ha/yr). Nitrogen applied to the watershed in April, June, August and October (16.8 kg/ha) 1991 was labeled with a (15)N tracer that increased the abundance of (15)N label from about 0.3663 atm % to 0.4366 atm %. Surface soil was the most important sink for the isotopically labelled N additions. We estimate using (15)N mass balancing that about 3/4 of the 16.8 kg N added during the 1991 growing season was retained in catchment soil and aboveground vegetation with soils being the dominant sink.
AN: 3551716

                                                                    630 of 1521  
TI: Phosphorus dynamics in the Amazon River and estuary
AU: Rao,-Ji-Long; Berner,-R.A.
AF: Dep. Geol. and Geophys. Yale Univ., New Haven, CT 06511, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 397-400
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: It has been revealed that rivers are the dominant channel for passing phosphorus into the ocean from the continents and that estuaries provide an important control on the exogenic cycle of phosphorus. However, the amount of phosphorus available for dissolutive transfer in bio-geochemical cycles is usually only a small fraction of the total-P in sediments, and there is no simple relationship between the amount of the transferable phosphorus and of the total phosphorus. Therefore, the determination of different forms of phosphorus in sediments becomes a critical step in order to get a reasonable global budget calculation for phosphorus and to understand the behavior of phosphorus in the exogenic cycle. In order to identify and quantify the different forms of phosphorus in sediment, a modified selective extraction technique has been developed which provides an optimized procedure with high precision. By means of the procedure, separate solid forms of phosphorus have been distinguished in marine and fluvial sediments from a number of Amazon locations.
AN: 3550673

                                                                    631 of 1521  
TI: Seasonal fluctuation of export and recycled production in different subareas of the Southern Ocean
AU: Goeyens,-L.; Dehairs,-F.
AF: Vrije Univ. Brussel, Pleinlaan, 2, B-1050 Brussels, Belgium
SO: BELGIAN-SCIENTIFIC-RESEARCH-PROGRAMME-ON-THE-ANTARCTIC.-SCIENTIFIC-RESULTS-OF-PHASE-TWO-10-1988-01-1992.-VOLUME-1.-PLANKTON-ECOLOGY-AND-MARINE-BIOGEOCHEMISTRY. Caschetto,-S.-ed. BRUSSELS-BELGIUM BELGIAN-SCIENCE-POLICY-OFFICE 1993 pp. 1-79
ST: BELG.-SCI.-RES.-PROG.-ANTARCT.
LA: English
ER: M (Marine)
AB: As the role of the Southern Ocean in the global biogeochemical carbon cycle is nowadays a leading concern in oceanographic research, this study emphasizes the specific effects of nitrogenous nutrients on the origin, development and fate of primary production. The inherent consequences of nitrogen utilization by phytoplankton for the channelling of organic nitrogen towards in-situ regeneration or towards sedimentation are investigated. The results obtained during different Antarctic cruises provides clear evidence for a distinction between different Antarctic ecosystems. Intensive new production, characteristic for fertile zones bordering the retreating ice edge was mainly conveyed towards the regenerating microbial network. This was mirrorred by enhanced ammonium availability and poor subsurface barite accumulation. On the other hand, the moderate to low primary production of open sea and close pack ice zones was available for export and only small amounts of the organic matter were remineralized in the upper layer. Additionally, we propose a scaling function, based on the correlation between barite concentrations in the subsurface Ba-maximum layer and oxygen concentrations in the O sub(2)-minimum layer observed for the Indian Ocean's sector. The equation provides a tool to estimate export of organic matter at any other Southern Ocean site starting with information on net barite accumulations over the season.
AN: 3550544

                                                                    632 of 1521  
TI: Coastal metabolism and the oceanic organic carbon balance
AU: Smith,-S.V.; Hollibaugh,-J.T.
AF: Dep. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
SO: REV.-GEOPHYS. 1993 vol. 31, no. 1, pp. 75-89
LA: English
ER: M (Marine)
AN: 3549939

                                                                    633 of 1521  
TI: Perception and selection of macrophyte detrital falls by the bathyal echinoid Stylocidaris lineata
AU: Young,-C.M.; Tyler,-P.A.; Emson,-R.H.; Gage,-J.D.
AF: Harbor Branch Oceanogr. Inst., 5600 Old Dixie Highw., Fort Pierce, FL 34946, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 7, pp. 1475-1486
LA: English
ER: M (Marine)
AB: Many deep-sea animals are known to exploit patchy food resources such as animal carcasses and sunken plant remains, but the mechanisms by which such foods are located remain generally unknown. The bathyal echinoid Stylocidaris lineata is an omnivorous deposit feeder that ingests sediment, dead animal remains, seagrass blades, and macroalgae such as Sargassum spp. Using a submersible, we investigated the ability of urchins to locate and exploit large falls of detritus. Individuals quickly arrived at packets of Thalassia testudinum and Sargassum spp. placed on the bottom, and they preferred these food items significantly over inert controls. However, the echinoids demonstrated no significant tendency to move toward the scent of upstream T. testudinum, either in situ or in laboratory flume experiments. Individuals moved at net speeds up to 30 m/day. The existing evidence suggests that S. lineata locate food by chance encounter, not distant chemoreception.
AN: 3548537

                                                                    634 of 1521  
TI: Dimethylsulphide and dimethylsulphoniopropionate in the Northeast Atlantic during the summer coccolithophore bloom
AU: Malin,-G.; Turner,-S.; Liss,-P.; Holligan,-P.; Harbour,-D.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 7, pp. 1487-1508
LA: English
ER: M (Marine)
AB: Concentrations of dimethylsulphide (DMS) and dissolved and particulate pools of its precursor, dimethylsulphoniopropionate (DMSP), were surveyed at the time of the summer bloom of coccolithophores in the Northeast Atlantic. The average DMS concentration was 12 nmol dm super(-3) (n = 158, range 1.06-93.8 nmol dm super(-3),  sigma n - 1 = 12.4). Statistically significant positive correlations between particulate DMSP and chlorophyll were found for samples from areas where coccolithophores accounted for 50% or more of the total carbon biomass. In these areas correlations between DMS and chlorophyll were not as strong but still significant. An estimate of the flux of DMS from the Northeast Atlantic in June-July (721 nmol m super(-2)/h) is of the same order as estimates for the southern North Sea at the same time of year (646 nmol m super(-2)/h). The data provide strong evidence for the importance of coccolithophores in the emission of DMS to the atmosphere. Comparison of flux data with budgets for airborne sulphur in Europe, reported by the European Monitoring and Evaluation Programme (EMEP), suggests that in summer the Northeast Atlantic may be a source of the sulphur deposited on adjacent land areas not strongly affected by anthropogenic sulphur sources. The overall results are discussed in relation to present knowledge of the global distribution of coccolithophores.
AN: 3547251

                                                                    635 of 1521  
TI: Radionuclide concentrations, fluxes, and residence times at Santa Monica and San Pedro Basins
AU: Wong,-Kai-M.; Jokela,-T.A.; Eagle,-R.J.; Brunk,-J.L.; Noshkin,-V.E.
AF: Environ. Sci. Div., Univ. California, Lawrence Livermore Natl. Lab., Livermore, CA 94550, USA
SO: PROG.-OCEANOGR. 1992 vol. 30, no. 1-4, pp. 353-357
LA: English
ER: M (Marine)
AB: Our participation in the California Basin Study (CaBS) in 1986-1988 has produced a radionuclide data base that allows us to trace the particle and water movement in the Santa Monica and the San Pedro Basins. These data enable us to calculate the radionuclide inventories in the three compartments of the basin, the water column, the settling particles, and the sediments. We have also determined the fluxes of several radionuclides associated with the sinking particles, the residence time in the water column, and the rate of deposition in the sediments. The biogeochemical environment of the Santa Monica Basin is uniquely suited to the application of tracer techniques to study the sedimentation processes. Subtle, but measurable changes in the distribution of fallout of  super(137)Cs from 1977 to 1988 were noted in the water column. Compared to the decay corrected measurement in 1973-1977 at the Geosecs and Farallon Islands stations off the coast of California,  super(137)Cs inventory in the water column in Santa Monica Basin has not changed significantly for the past decade. Increases in the deep water concentration profiles of  super(137)Cs partially resulted from particle transport and diagenetic release of cesium in the deep water. The major  super(137)Cs inventory (> 70%) resides in the upper 400m of water, with a mean residence time of 480  plus or minus  90 years. Less than 11% of the total  super(137)Cs inventory was found in the sediments at water depths of 900m in 1987. Unlike  super(137)Cs, more than 80% of the fallout  super(239+240)Pu has been deposited in the Santa Monica Basin sediments. A mean residence time of 13  plus or minus  12 years was measured for  super(239+240)Pu in the basin water. The ubiquitous  super(239+240)Pu subsurface concentration maximum observed in the Pacific oceanic waters at about 350m depth is also evident in the basin water. We have no definitive explanation for the persistence of the subsurface maximum except that it appears to be correlated with the density gradient at 26.5 to 26.9 sigma-t.
AN: 3546899

                                                                    636 of 1521  
TI: Post-mortem formation of inorganic arsenic from arsenobetaine in a shark under natural conditions
AU: Hanaoka,-K.; Kogure,-T.; Miura,-Y.; Tagawa,-S.; Kaise,-T.
AF: Dep. Food Sci. and Technol., Shimonseki Univ. Fish., Nagata-honmachi 2-7-1, Shimonoseki 759-65, Japan
SO: CHEMOSPHERE 1993 vol. 27, no. 11, pp. 2163-2167
LA: English
ER: M (Marine)
AB: The ubiquity of an organic arsenic compound, arsenobetaine [(CH sub(3)) sub(3)As super(+)CH sub(2)COO super(-)], in marine animals is wellknown. On the other hand, the fate of it is not well known in vivo. The degradation of arsenobetaine accumulated in a shark to inorganic arsenic was shown to occur in a natural environment. This means that arsenobetaine bioconverted from inorganic arsenic from sea-water is degraded to original inorganic arsenic.
AN: 3545368

                                                                    637 of 1521  
TI: Studies of iron bacteria from a mangrove ecosystem in Goa and Konkan
AU: Panchanadikar,-V.V.
AF: Reg. Res. Lab., Bhubaneswar-751013, India
SO: INT.-J.-ENVIRON.-STUD.,-SECT.-A 1993 vol. 45, no. 1, pp. 17-21
LA: English
ER: B (Brackish)
AB: Studies of microbial ecology have evoked considerable interest in recent years with the natural ecosystem threatened by pollution due to industrialisation, mining etc. Iron mobilisation in a mangrove ecosystem is a complex process. There are a number of factors affecting mobilisation of iron in mangrove swamps, like the pH of soil, dissolved oxygen, iron source, etc. Our paper describes experiments designed to look for the presence of iron-reacting bacteria in mining area of Goa, and their activity was compared with iron bacteria found in the mangrove regions of the Konkan (non-mining) area. It was observed that the activity of both iron-oxidising and iron-reducing bacteria was higher in mining areas compared to that in non-mining areas, since ample substrate was available in the former.
AN: 3545296

                                                                    638 of 1521  
TI: Measurements of seasonal rates and annual budgets of organic carbon fluxes in an Antarctic coastal environment at Signy Island, South Orkney Islands, suggest a broad balance between production and decomposition
AU: Nedwell,-D.B.; Walker,-T.R.; Ellis-Evans,-J.C.; Clarke,-A.
AF: Dep. Biol., Univ. Essex, Colchester CO4 3SQ, UK
SO: APPL.-ENVIRON.-MICROBIOL. 1993 vol. 59, no. 12, pp. 3989-3995
LA: English
ER: M (Marine)
AB: The authors report here the first comprehensive seasonal study of benthic microbial activity in an Antarctic coastal environment. Measurements were made from December 1990 to February 1992 of oxygen uptake and sulfate reduction by inshore coastal sediments at Signy Island, South Orkney Islands, Antarctica. From these measurements the rate of benthic mineralization of organic matter was calculated. In addition, both the deposition rate of organic matter to the bottom sediment and the organic carbon content of the bottom sediment were measured during the same period. Organic matter input to the sediment was small under winter ice cover, and the benthic respiratory activity and the organic content of the surface sediment declined during this period as available organic matter was depleted. On an annual basis, about 32% of benthic organic matter mineralization was anoxic, but the proportion of anoxic compared with oxic mineralization increased during the winter as organic matter was increasingly buried by the amphipod infauna. Fresh organic input occurred as the sea ice melted and ice algae biomass sedimented onto the bottom, and input was sustained during the spring after ice breakup by continued primary production in the water column. The benthic respiratory rate and benthic organic matter content correspondingly increased towards the end of winter with the input of this fresh organic matter. The rates of oxygen uptake during the southern summer (80 to 90 mmol of O sub(2) m super(-2)/day) were as high as those reported for other sediments at much higher environmental temperatures, and the annual mineralization of organic matter was equally high (12 mol of C m super(-2)/year). Seasonal variations of benthic activity in this antarctic coastal sediment were regulated by the input and availability of organic matter and not by seasonal water temperature, which was relatively constant at between -1.8 and 0.5 degree C. We conclude that despite the low environmental temperature, organic matter degradation broadly balanced organic matter production, although there may be significant interrannual variations in the sources of the organic matter inputs.
AN: 3539852

                                                                    639 of 1521  
TI: Isotopic and biochemical composition of particulate organic matter in a shallow water estuary (Great Ouse, North Sea, England)
AU: Fichez,-R.; Dennis,-P.; Fontaine,-M.F.; Jickells,-T.D.
AF: Cent. ORSTOM Tahiti, B.P. 529, Papeete, Tahiti, French Polynesia
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 263-276
LA: English
ER: M (Marine); B (Brackish)
AB: The biogeochemistry of particulate organic matter was studied in the Great Ouse estuary draining to the North Sea embayement known as the Wash from March 1990 to January 1991. Eleven locations were sampled monthly on a 50 km transect across the shallow estuary from the tidal weir to the middle of the Wash. Particulate organic carbon (POC) and total carbohydrate, protein and lipid analyses were combined with the determination of stable carbon isotopes.  delta  super(13)C often increased from -30ppt in the river to -22ppt in the tidal freshwater reach. The mixing zone between fresh and marine tidal waters displayed only a slight increase in  delta  super(13)C to -19ppt. The change in  delta  super(13)C values in the freshwater tidal reach demonstrated that mixing of riverborne and marine suspended POC was not the only process affecting the carbon stable isotope composition. Complementary sources, interfering considerably with the two end-member sources, may be identified as autochthonous primary production and resuspension of sediment that may be transported upstream. The respective importance of these sources is subject to seasonal variation. From March to August, high concentrations in carbohydrate and protein through the whole estuary indicate that despite turbidity significant primary production occurred. The proportional importance of the uncharacterized fraction of POC, which is considered as complex organic matter, was high from September to January and low from March to August. During most of the year, the biochemical compositions of particulate organic matter in the turbidity maximum and the rest of the estuary were similar. This contradicted the principle that owing to the long residence times of particles degradation processes largely dominate the production processes within the turbidity maximum. The occurrence of significant in situ production in such shallow water estuaries may partially compensate for the degradation of suspended particulate organics, resulting in a complex relationship between the biogeochemical cycling and the fate of nutrients.
AN: 3539734

                                                                    640 of 1521  
TI: Nutrient processing and the development of tidal creek ecosystems
AU: Dame,-R.F.; Gardner,-L.R.
AF: Coast. Carolina Coll. Univ. South Carolina, Conway, SC 29526, USA
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 175-183
LA: English
ER: M (Marine)
AB: The North Inlet marsh-estuarine system encompasses the spectrum of interaction between the ocean and the uplands typical of the southeastern United States. The system is an ebb-dominated, bar-built estuary with good flow connection to the sea and some freshwater input. The North Inlet basin has evolved from a forested, relic, beach-ridge terrain under a regime of slowly rising sea level (2 mm/year). This mode of development is supported by historic tide gage data,  super(210)Pb dating of sediment cores, the presence of spodic soil horizons and tree roots at shallow depths beneath the marsh surface, and the presence of relic 'cat eye' ponds at the edge of the salt marsh. As sea level rises, the boundary between forest and salt marsh recedes upslope and forest spodosols are gradually transformed into marsh soils by salinization, the deposition and mixing of marine mud into the upper horizons of the forest soil and the accumulation of reduced sulfur via sulfate reduction. As a forest watershed is transformed into a salt-marsh basin, the hydraulic geometry of the original, black-water (fresh) stream increases to accommodate the increasing volumes of tidal discharge. Forest sands move seaward while marine muds are transported into the basin. As water moves between the forest and the sea, it passes through creeks in different developmental stages. Large mature creeks interact with the ocean while young, ephemeral creeks drain the uplands and intertidal marsh zones. Intermediate stage creeks connect these two and are characterized by the presence of oyster reefs. Net nutrient fluxes appear to be different in each developmental stage.
AN: 3539727

                                                                    641 of 1521  
TI: The biogeochemistry of nutrients and trace metals in Hood Canal, a Puget Sound fjord
AU: Paulson,-A.J.; Curl,-H.C.,Jr.; Feely,-R.A.
AF: Spokane Res. Cent., U.S. Bur. Mines, E. 315 Montgomery Ave., Spokane, WA 99207-2291, USA
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 157-173
LA: English
ER: M (Marine); B (Brackish)
AB: The summer stratification of the surface layer of much of Hood Canal (a Puget Sound fjord) results in a surface layer low in nutrients and a deep layer low in dissolved oxygen and enriched in nutrients. Deviations from the dissolved oxygen:nutrient linear relationships are manifestations of several chemical and biological processes. The low dissolved oxygen concentrations (50  mu mol) result in the redistribution of Fe in the sediment column while Mn is redistributed within the water column. Trace metals are also taken up by organisms in the surface layer and regenerated in the deep layer in the order Zn >> Cd > Cu = Ni. Regenerated Zn is adsorbed on to resuspended bottom sediments that are enriched in Fe oxyhydroxides while Cd is adsorbed throughout the water column. Particulate distributions of Cu and Ni indicate these metals are also participating in biogeochemical cycles, albeit to a lesser extent.
AN: 3539726

                                                                    642 of 1521  
TI: Distributional features and fluxes of dissolved nitrogen, phosphorus and silicon in the Hangzhou Bay
AU: Gao,-Shengquan; Yu,-Guohui; Wang,-Yuhen
AF: Second Inst. Oceanogr., SOA, Hangzhou 310012, People's Rep. China
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 65-81
LA: English
ER: M (Marine); B (Brackish)
AB: Dissolved nitrate, ammonia, nitrite, phosphate and silicate were measured seasonally near Hangzhou Bay mouth and its adjacent area from 1981 to 1982 and in the upper bay from 1989 to 1990. Because of agricultural activities and increasing discharge of industrial and domestic wastes in that area, the dissolved inorganic nitrogen (average 59.5  mu mol) and phosphorus (average 1.26  mu mol) were significantly higher in the Hangzhou Bay than in the other estuaries, while the silicate level corresponded to the global mean value. The nutrient distributions and variations were dominated by different controls in the different seasons, depending mainly on tidal conditions, river flow and their estuarine processes. The nutrient behaviors of dissolved nitrate, phosphate and silicate were different for each nutrient in the Hangzhou Bay. Silicate was closely conservative in most cases; nitrate exhibited marked biological removal at intermediate salinity and phosphate seemed to be buffered by the suspended sediments. The effluxes of dissolved inorganic nitrogen, phosphorus and silicon were estimated to be about 63 x 10 super(3) tons N/year, 2.8 x 10 super(3) tons P/year and 160 x 10 super(3) tons Si/year, respectively.
AN: 3539721

                                                                    643 of 1521  
TI: Distribution and composition of particulate organic matter in the Ross Sea (Antarctica)
AU: Fabiano,-M.; Povero,-P.; Danovaro,-R.
AF: Dip. Biol. Anim. Ecol., Univ. Cagliari, V. le Poetto 1, Cagliari, Italy
SO: POLAR-BIOL. 1993 vol. 13, no. 8, pp. 525-533
LA: English
ER: M (Marine)
AB: The biochemical composition and spatial distribution of particulate organic matter (POM) were studied in the Ross Sea (Antarctica) in summer 1989 to assess the quantitative role of organic carbon fractions in the cycling of organic matter in the water column. Large differences in chemical composition were observed between surface and deep layers. The results indicated that, despite large geographical differences, POM was quite homogeneous, of phytoplankton origin and mostly detrita1. Different ratios were used to investigate the changes in biochemical composition of particulate organic matter in relation to the ice-melting: C:N (organic carbon: organic nitrogen ratio) and C-POM:POC (sum of carbohydrate, protein and lipid carbon: total organic carbon ratio) were used to analyse the percentage of refractory organic material. PPRT:PCHO (protein: carbohydrate ratio) were used to establish POM "age" and RNA : DNA ratios as a relative measure of particulate activity; POC:Chla and N-PPRT:Chla ratios were used to estimate the autotrophic contribution to the suspended particulate organic matter. Despite its low caloric value (5.3 Kcal/g POM), an high caloric content in the photic layer (1.6 Kcal/m super(3) of POM and 2.5 Kcal/m  super(3) of POC) was found thus indicating that a large amount of food was available in highter tropic levels.
AN: 3538876

                                                                    644 of 1521  
TI: Applications of analytical chemistry to oceanic carbon cycle studies
CA: National Research Counc., Washington, DC (USA)
SO: WASHINGTON,-DC-USA NATIONAL-ACADEMY-PRESS 1993 85 pp
LA: English
ER: M (Marine)
AB: This report highlights the state of the art of measurement technologies offering new promise for ocean measurements. In particular, the group focused on new techniques for measuring seawater analytes that are important for understanding key aspects of the ocean's role in the global carbon cycle. The committee also noted other seawater analytes whose improved measurement would contribute to a better understanding of ocean processes. The report does not encompass all areas of chemical oceanography; instead, it highlights a subset of the possible measurements that could be useful for obtaining improved understanding of the global carbon cycle. The report focuses on in situ measurements of dissolved analytes in seawater that might not be feasible in the near future but could play an important role in global ocean observations of the future. The committee believes that the most difficult problem is in designing sensors of the desired selectivity, stability, and sensitivity for dissolved analytes in the open ocean. This report identifies technical hurdles and opportunities and discusses the role that government and academia can play in overcoming the nontechnical barriers to successful research, development, and transfer of these technologies to the ocean science community.
AN: 3538833

                                                                    645 of 1521  
TI: A review of the export of carbon in river water: Fluxes and processes
AU: Hope,-D.; Billett,-M.F.; Cresser,-M.S.
AF: Dep. Plant Soil Sci., Univ. Aberdeen, Cruickshank Build., Aberdeen AB9 2UD, UK
SO: ENVIRON.-POLLUT. 1994 vol. 84, no. 3, pp. 301-324
LA: English
ER: F (Freshwater)
AB: This review summarizes data on exports of carbon from a large number of temperate and boreal catchments in North America, Europe and New Zealand. Organic carbon losses, usually dominated by dissolved organic matter, show relatively little variation, most catchments exporting between 10 and 100 kg C/ha/yr. Inorganic carbon exports occur at a similar rate. However, a lack of information on the flux of particulate organic carbon and dissolved CO sub(2) is highlighted, particularly for rivers in Europe. Processes regulating the flux of organic carbon to streams and its subsequent fate in-stream are reviewed, along with the effects of land use and acidification on these processes. The size of the global riverine flux of carbon in relation to the global carbon cycle and the possible effects of environmental change on the export of carbon in rivers are considered.
AN: 3538111

                                                                    646 of 1521  
TI: Atmospheric input of inorganic nitrogen to Delaware Bay
AU: Scudlark,-J.R.; Church,-T.M.
AF: Coll. Mar. Stud., Univ. Delaware, 700 Pilottown Rd., Lewes, DE 19958, USA
SO: ESTUARIES 1993 vol. 16, no. 4, pp. 747-759
LA: English
ER: M (Marine); B (Brackish)
AB: The coastal waters of the Mid-Atlantic region of the United States receive inputs of atmospheric pollutants as a consequence of being located downwind from major industrial and urban emissions. These inputs are potentially the largest received by any marine area of the country. Of current interest is the atmospheric input of dissolved inorganic nitrogen (DIN = NO sub(3) super(-) + NH sub(4) super(+)). We have conducted a first-order examination of the magnitude of atmospheric DIN deposition relative to other large-scale inputs for Delaware Bay, a partially urbanized mid-Atlantic coastal plain estuary. The following loading terms: direct atmospheric deposition, indirect atmospheric loading, urban point discharges, fluvial input, benthic flux, and salt marsh export were evaluated. On an annual basis, municipal-industrial effluents provide a dominant source (ca. 40%) of the DIN input to the estuary. Total (wet plus dry) atmospheric deposition accounts for about 15% of the total annual DIN inputs. However, during summer, which is characterized by low river-flow and seasonally maximum atmospheric loading, this figure increases to around 25%. Although atmospheric input can satisfy only a fraction of the primary production demands, this summer flux may represent an ecologically important source of external DIN, half of which is directly deposited to surface photic zones where it is readily available for biological uptake.
AN: 3536891

                                                                    647 of 1521  
TI: Beaver pond biogeochemistry: Acid neutralizing capacity generation in a headwater wetland
AU: Cirmo,-C.P.; Driscoll,-C.T.
AF: Dep. Civ. and Environ. Eng., Syracuse Univ., Syracuse, NY 13244, USA
SO: WETLANDS 1993 vol. 13, no. 4, pp. 277-292
LA: English
ER: F (Freshwater)
AB: A beaver pond and its associated inlet and outlet waters in the Adirondack Mountains of New York were monitored for major chemical solutes for 26 months in an effort to quantify underlying chemical controls on the production and consumption of acid neutralizing capacity (ANC). The pond was a net annual sink for inlet Al, SO sub(4) super(2-), NO sub(3) super(-), and H sub(4)SiO sub(4). The pond was a net annual source of dissolved organic carbon (DOC), NH sub(4) super(+), and Fe super(2+). Losses of ANC resulting from Al and basic cation retention, as well as organic anion release (RCOO super(-)) associated with DOC, were more than offset by SO sub(4) super(2-) and NO sub(3) super(-) retention and Fe super(2+) and NH sub(4) super(+) release, resulting in a net production of ANC. Rates of ANC generation were 120 meq m super(-2)/yr and 310 meq m super(-2)/yr, respectively (based on pond surface area), for the non-summer (October-June) and summer (July-September) periods. Seasonal variations in ANC in the outlet stream were largely associated with Fe super(2+) and DOC release, while ANC in the upland inlet stream was associated with Al, NO sub(3) super(-), and basic cations, with much less seasonal variation. Controls on stream chemistry were temporally and longitudinally different for the inlet and outlet streams. The shift to seasonal control of outlet stream ANC by processes associated with organic matter decomposition reactions and anaerobic zone nutrient transformations may be characteristic of headwater wetlands in temperate zones with seasonal temperature extremes. Beaver impoundments and wetlands may also be important in the upstream mobilization or retention of geologically bound solutes like Al, Fe, and H sub(4)SiO sub(4). Headwater wetlands, as sinks for solutes associated with acidic deposition and watershed acidification (i.e., SO sub(4) super(2-), NO sub(3) super(-), and Al), may play a role in the amelioration of the effects of these solutes on downstream receiving waters and associated biota. Depending on their location in relation to drainage patterns, these ponded systems may influence the nutrient dynamics of receiving waters through nitrogen transformations and organic carbon cycling.
AN: 3536863

                                                                    648 of 1521  
TI: The internal consistency of CO sub(2) measurements in the Equatorial Pacific
AU: Millero,-F.J.; Byrne,-R.H.; Wanninkhof,-R.; Feely,-R.; Clayton,-T.; Murphy,-P.; Lamb,-M.F.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: MAR.-CHEM. 1993 vol. 44, no. 2-4, pp. 269-280
LA: English
ER: M (Marine)
AB: During a recent NOAA JGOFS Equatorial Pacific cruise all four analytical parameters of the carbonate system were measured-pH, total alkalinity (TA), total carbon dioxide (TCO sub(2)), and the fugacity of carbon dioxide (fCO sub(2)). The measurements made during leg 2 on surface waters have been used to examine the internal consistency of the carbon dioxide system in these waters. The internal consistency of the measurements was examined by using various inputs of the measured parameters (pH-TA, pH-TCO sub(2), pH-fCO sub(2)-TA, fCO sub(2)-TA, fCO sub(2)-TCO sub(2) and TA-TCO sub(2)) to calculate the components of the CO sub(2) system. The results indicate that the measurements have an internal consistency of  plus or minus 0.003-0.006 in pH,  plus or minus 5-7  mu mol/kg in TA,  plus or minus 5-7  mu mol/kg in TCO sub(2) and  plus or minus 6-9  mu Atm in fCO sub(2) if reliable constants are used for the dissociation of carbonic acid in seawater. These results indicate that our present understanding of the thermodynamics of the carbonate system in seawater is close to the present accuracy in measuring the various parameters of the system ( plus or minus 0.002 in pH,  plus or minus 4  mu mol/kg in TA,  plus or minus 2  mu mol/kg in TCO sub(2) and  plus or minus 2  mu Atm in fCO sub(2)).
AN: 3536790

                                                                    649 of 1521  
TI: Biogenic sulfur compounds in seawater and the atmosphere of the Antarctic region
AU: Staubes,-R.; Georgii,-H.W.
AF: Inst. Meteorol. and Geophys., Johann Wolfgang Goethe Univ., 6000 Frankfurt/Main 1, FRG
CO: Symp. on the Tropospheric Chemistry of the Antarctic Region, Boulder, CO (USA), Jun 1991
SO: TELLUS-B-CHEM.-PHYS.-METEOROL. 1993 vol. 45B, no. 2, pp. 127-137
NT: Special Issue II.
LA: English
ER: M (Marine)
AB: Shipboard measurements of dimethyl sulfide (DMS), carbonyl sulfide (COS) and carbon disulfide (CS sub(2)) in seawater and the marine boundary layer were performed during a cruise between Punta Arenas (Chile) and Cape Town (South Africa) through the Weddell Sea in November/December 1990. The DMS concentrations in seawater averaged to 71 ngS/l, atmospheric DMS mixing ratios showed a range between 2 and 1048 pptv. The COS levels in seawater showed a mean of 3.5 ngS/l with minor variability. The concentrations of CS sub(2) in the remote marine boundary layer were below the detection limit of 7 pptv, with enhanced concentrations of about 35 pptv observed in air masses influenced by continental inputs.
AN: 3536744

                                                                    650 of 1521  
TI: Bromoalkane production by Antarctic ice algae
AU: Sturges,-W.T.; Sullivan,-C.W.; Schnell,-R.C.; Heidt,-L.E.; Pollock,-W.H.
AF: Coop. Inst. Res. Environ. Sci., Univ. Colorado, Boulder, CO 80309-0449, USA
CO: Symp. on the Tropospheric Chemistry of the Antarctic Region, Boulder, CO (USA), Jun 1991
SO: TELLUS-B-CHEM.-PHYS.-METEOROL. 1993 vol. 45B, no. 2, pp. 120-126
NT: Special Issue II.
LA: English
ER: M (Marine)
AB: Ice microalgae, collected from the underside of annual sea ice in McMurdo Sound, Antarctica, were found to contain and release to seawater a number of brominated hydrocarbons. These included bromoform, dibromomethane, mixed bromochloromethanes, and methyl bromide. Atmospheric measurements in the McMurdo Sound vicinity revealed the presence of bromoform and methyl bromide in the lower atmosphere, with lowest concentrations inland, further indicating that biogenic activity in the Sound is a source of organic bromine gases to the Antarctic atmosphere. This may have important implications for boundary layer chemistry in Antarctica. In the Arctic, the presence of bromoform has been linked to loss of surface ozone in the spring. We report here preliminary evidence for similar surface ozone loss at McMurdo Station.
AN: 3535612

                                                                    651 of 1521  
TI: Global cyclostratigraphy: A model of carbonate growth patterns
AU: Li,-Y.Y.; Lerche,-I.; Perlmutter,-M.A.
AF: Dep. Geol. Sci., Univ. South Carolina, Columbia, SC 29208, USA
SO: MAR.-PET.-GEOL. 1993 vol. 10, no. 6, pp. 620-631
LA: English
ER: M (Marine)
AB: Cyclostratigraphy is the study of cyclic depositional patterns produced by climatic and tectonic processes. A global-scale quantitative cyclostratigraphic model is described which simulates carbonate growth patterns controlled by tectonic and climatic processes. The model uses seven factors simulating the effects of physical and chemical environments on the deposition rates of carbonate accumulations. These factors are sea-level change, the rate of basement subsidence, food supply (influence of nutrients), available sunlight, temperature, salinity and dissolved oxygen. The factors are considered as functions of climatic and tectonic processes. The model also integrates Milankovitch-induced short-term climatic changes with the long-term tectonic evolution of basins to examine the potential carbonate accumulation patterns. The two-dimensional computer model results provided here show that: (1) carbonate growth patterns in different climates and under different tectonic processes can be modelled quantitatively; (2) carbonate production increases towards the equator (decreasing latitude) as the temperature and nutrition supply increase in tropical belts, and production changes because of expansion or contraction of the tropical belt in different climatic periods; (3) when matched with the turbidity, the model describes different carbonate accumulation patterns in different climatic patterns; (4) at either abnormally high or low salinity, carbonate accumulation rates decline sharply, and the salinity becomes normal away from the strand line; and (5) cyclic sea-level changes cause a cyclic change of carbonate accumulation. A case study is presented from the Upper Pennsylvanian of Texas. The simulation results indicate that carbonate growth patterns observed from field, well or seismic data are accurately modelled by the quantitative procedure given here.
AN: 3534079

                                                                    652 of 1521  
TI: Distribution and sedimentation of organic matter during the inter-monsoon period off Oman (West Arabian Sea)
AU: Passow,-U.; Peinert,-R.; Zeitzschel,-B.
AF: Mar. Sci. Inst., Univ. California, Santa Barbara, CA 93106, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 833-849
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Temperature, salinity and nutrient concentrations, as well as suspended particles and vertical flux of particles were measured during a drogue study in the spring inter-monsoon period of 1987 off Oman. In addition, horizontal variability of temperature, nutrients and in vivo fluorescence were documented during two grid surveys. An oligotrophic type of system typical for low latitudes with a stratified water column was anticipated at this season. However, although no upwelling occurred, some stations exhibited high near-surface chl a concentrations (2  mu g l super(-1)), a predominance of diatoms and high sedimentation rates (up to 0.4 gC m super(-2) day super(-1)) comparable to upwelling regimes or spring blooms of higher latitudes. Different stages of the development and decline of a diatom bloom and of the transition towards more oligotrophic conditions were found to coexist on scales of 10 nautical miles or less.
AN: 3531584

                                                                    653 of 1521  
TI: Short-term sedimentation patterns in the northern Indian Ocean
AU: Pollehne,-F.; Zeitzschel,-B.; Peinert,-R.
AF: Inst. Ostseeforschung, Seestr. 15, O-2530, Rostock-Warnemuende, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 821-831
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The flux of particles from the photic zone was monitored in one open ocean and two shelf stations in the northern Indian Ocean by means of drifting sediment traps in the inter-monsoon period, from March to June 1987. Samples were collected over daily intervals and analysed for organic carbon, nitrogen, total phosphorus and silica. Flux rates of all elements differed by up to a factor of 10 between the Oman shelf and the open ocean area. Mean rates of carbon sedimentation were 13.6 and 1.7 mmol C/m super(2)/day, respectively. On the Pakistan shelf, however, sedimentation rates were in the same low range as in the open ocean. These differences, particularly between the two shelf regions, were due to the different types of pelagic systems in the respective photic zones. The presence of nitrate in surface water of the Oman shelf permitted "new" production, which consequently led to enhanced particle export. In the open ocean and the Pakistan shelf, typical tropical recycling systems retained material by intense regeneration of nutrients in the surface layer. These differences also were reflected in the composition of the sedimenting particles. Changes in production-respiration equilibria in the photic zone lead to rapid shifts in the carbon/silica and carbon/nitrogen ratios of trapped material. Thus short term sedimentation measurements can provide valuable information on structural and functional variations in pelagic productivity.
AN: 3531583

                                                                    654 of 1521  
TI: Aspects of horizontal distribution and diet of myctophid fish in the Arabian Sea with reference to the deep water oxygen deficiency
AU: Kinzer,-J.; Boettger-Schnack,-R.; Schulz,-K.
AF: Inst. Meereskd., Univ. Kiel, D-2300 Kiel, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 783-800
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Horizontal distribution of myctophid fishes were studied from two transects in the Arabian Sea in 1987. Species numbers exhibited a south-north decline in diversity, with only half of the fish taxa occupying the northeastern region. Diaphus arabicus was the dominant species both in the south and north. All recorded myctophid fish species migrate in a diel pattern, residing during daytime at depths of extremely low oxygen levels (<0.1 ml O sub(2)/l) and foraging in the oxygen-rich surface layer at night. Feeding patterns were determined for the six most abundant myctophid species. All species appeared to be opportunistic predators that prey on a comparatively narrow food spectrum consisting principally of small to medium sized copepods. Numerically, non-calanoid copepods (with Oncaea conifera and O. venusta dominating) made up to 70% of the diet of D. arabicus and Bolinichthys longipes. Of the 26 calanoid copepod species identified from the six myctophid taxa, the genera Euchaeta, Pleuromamma and Candacia generally dominated in the stomachs, with P. indica constituting between 21 and 95% (by numbers) of the calanoid copepod prey.
AN: 3531582

                                                                    655 of 1521  
TI: A comparative study on the influence of the pycnocline on the vertical distribution of fish larvae and cephalopod paralarvae in three ecologically different areas of the Arabian Sea
AU: Roepke,-A.; Nellen,-W.; Piatkowski,-U.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Div. Mar. Biol. and Fish., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 801-819
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Zooplankton sampling took place during cruise 5 Leg 3 of the R.V. Meteor (March-June 1987) in three hydrographically and ecologically different areas of the Arabian Sea (Indian Ocean): an upwelling area at the coast of Oman; an oligotroph area in the central Arabian Sea; and a shelf area off the coast of Pakistan. All three areas were expected to have similar ichthyoplankton and cephalopod components and similar light conditions. These are important prerequisites for the present comparative study, which is concerned with the importance of the structure of the water column (physical stability and prey availability), compared with the influence of the light intensity (day/night) on the vertical distribution of species and size classes of fish larvae and cephalopod paralarvae in the subtropical pelagial.
AN: 3531581

                                                                    656 of 1521  
TI: Modeling study of the vertical distribution and transport of manganese in Puget Sound
AU: Cudaback,-C.N.; Paulson,-A.J.; Lavelle,-J.W.
CA: National Oceanic and Atmospheric Adm., Seattle, WA (USA). Pacific Marine Environmental Lab.
SO: NOAA-TECH.-MEMO. 1991 27 pp
RN: NOAA-TM-ERL-PMEL-93 (NOAATMERLPMEL93)
LA: English
ER: M (Marine); B (Brackish)
AB: The fate of many toxic trace metals in estuaries is controlled by their adsorption onto manganese enriched particles, although Mn itself is not considered toxic. The geochemical cycle of estuarine manganese has been studied by a variety of approaches. A one-dimensional vertical distribution and transport model tracing the fate of Mn in dissolved and fine particulate forms and Mn associated with rapidly settling aggregates is developed and results are compared with measurements. Those measurements take the form of vertical profiles of dissolved and particulate Mn concentrations measured in the water column at one station in central Puget Sound. The model provides a framework relating sources, sinks, distributions and fluxes of Mn in a quantitative manner. The model accurately reproduces the vertical distributions of dissolved and particulate Mn, but shows excessive vertical flux of Mn. The model suggests that particles in each of two size classes should carry nearly the same loading of Mn, but measurements show significantly less Mn loading on macroaggregates than on fine particles. Mn budgets from model results allow comparison of major Mn fluxes in Puget Sound. The flux of Mn into the central main basin in particulate form is about half the diffusive flux of dissolved Mn from the bottom. A significant fraction of the riverine flux of particulate Mn is advected out of Puget Sound in dissolved form.
AN: 3531554

                                                                    657 of 1521  
TI: Amino acid composition of suspended particles, sediment-trap material, and benthic sediment in the Potomac Estuary
AU: Sigleo,-A.C.; Shultz,-D.J.
AF: Pac. Ecosyst. Branch, U.S. EPA, Newport, OR 97365-5260, USA
CO: 11. Bienn. Int. Estuarine Research Conf., San Francisco, CA (USA), 10-14 Nov 1991
SO: TRACE-CONTAMINANTS-AND-NUTRIENTS-IN-ESTUARIES. 1993 vol. 16, no. 3A pp. 405-415
ST: ESTUARIES vol. 16, no. 3A
LA: English
ER: M (Marine); B (Brackish)
AB: Sediment trap deployments in estuaries provide a method for estimating the amount of organic material transported to the sediments from the euphotic zone. The amino acid composition of suspended particles, benthic sediment, and sediment-trap material collected at 2.4 m, 5.8 m, and 7.9 m depths in the Potomac Estuary was determined in stratified summer waters, and in well-mixed oxygenated waters (DO) in late fall. The total vertical flow, or flux, of material into the top traps ranged from 3 g/m super(2)/d in August to 4.9 g/m super(2)/d in October. The carbon and nitrogen fluxes increased in the deepest traps relative to the surface traps during both sampling periods, along with that of the total material flux (up to 47.3 g/m super(2)/d in the deepest trap), although the actual weight percent of organic carbon and organic nitrogen decreased with depth. Amino acid concentrations ranged from 129 mg/g in surface water particulate material to 22 mg/g in particulate material in 9-m-deep waters and in the benthic sediment. Amino acid concentrations from 2.4-m-depth sediment traps averaged 104  plus or minus  29 mg/g in stratified waters and 164  plus or minus  81 mg/g in well-mixed waters. The deep trap samples averaged 77.3  plus or minus  4.8 mg/g amino acids in summer waters and 37  plus or minus  16 mg/g in oxygenated fall waters. Amino acids comprised 13% to 39% of the organic carbon and 12% to 89% of the organic nitrogen in these samples. Analysis of the flux results suggest that resuspension combined with lateral advection from adjacent slopes can account for up to 27% of the material in the deep traps when the estuary was well-mixed and unstratified. When the estuary was stratified in late summer, the amino acid carbon produced by primary productivity in the euphotic zone decreased by 85% (86% for total organic carbon) at the pycnocline at 6 m depth, leaving up to 15% of the vertical organic flux available for benthic sediment deposition.
AN: 3530945

                                                                    658 of 1521  
TI: Silver in San Francisco Bay estuarine waters
AU: Smith,-G.J.; Flegal,-A.R.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
CO: 11. Bienn. Int. Estuarine Research Conf., San Francisco, CA (USA), 10-14 Nov 1991
SO: TRACE-CONTAMINANTS-AND-NUTRIENTS-IN-ESTUARIES. 1993 vol. 16, no. 3A pp. 547-558
ST: ESTUARIES vol. 16, no. 3A
LA: English
ER: M (Marine); B (Brackish)
AB: Spatial gradients of silver concentrations in the surface waters of San Francisco Bay reveal substantial anthropogenic perturbations of the biogeochemical cycle of the element throughout the estuarine system. The most pronounced perturbations are in the south bay, where dissolved (<0.45  mu m) silver concentrations are as high as 250 pM. This is more than one order-of-magnitude above baseline concentrations in the northern reach of the estuary (6 pM) and approximately two orders-of-magnitude above natural concentrations in adjacent coastal waters (3 pM). The excess silver is primarily attributed to wastewater discharges of industrial silver to the estuary on the order of 20 kg/d. The contamination is most evident in the south bay, where wastewater discharges of silver are on the order of 10 kg/d and natural freshwater discharges are relatively insignificant. The limited amount of freshwater flushing in the south bay was exacerbated by persistent drought conditions during the study period. This extended the hydraulic residence time in the south bay ( greater than or equal to 160 d), and revealed the apparent seasonal benthic fluxes of silver from anthropogenically contaminated sediments. These were conservatively estimated to average ) 16 nmol m super(-2)/d in the south bay, which is sufficient to replace all of the dissolved silver in the south bay within 22 d. Benthic fluxes of silver throughout the estuary were estimated to average ) 11 nmol m super(-2)/d, with an annual input of approximately 540 kg/yr of silver to the system. This dwarfs the annual fluvial input of silver during the study period (12 kg yr super(-1)), and is equivalent to approximately 10% of the annual anthropogenic input of silver to the estuary (3,700-7,200 kg/yr). It is further speculated that benthic fluxes of silver may be greater than or equal to waste water fluxes of silver during periods of intense diagenic remobilization. However, all inputs of dissolved silver to the estuary are efficiently sorbed by suspended particulates, as evidenced by the relatively constant conditional distribution coefficient for silver throughout the estuary (K sub(d) )  10 super(5)).
AN: 3530930

                                                                    659 of 1521  
TI: Trace contaminants and nutrients in estuaries: The importance of process interdependence
AU: Kuwabara,-J.S.; Baker,-J.E.
AF: Water Resour. Div., U.S. Geol. Surv., 345 Middlefield Rd., Mail Stop 465, Menlo Park, CA 94025, USA
CO: 11. Bienn. Int. Estuarine Research Conf., San Francisco, CA (USA), 10-14 Nov 1991
SO: ESTUARIES 1993 vol. 16, no. 3A, 190 pp
LA: English
ER: M (Marine); B (Brackish)
AB: This issue is dedicated to studies that attempt to expand our understanding of how inorganic and organic solutes are transported, transformed, and distributed in estuaries.
AN: 3530928

                                                                    660 of 1521  
TI: Evaluation of  super(55)Fe as a tracer of Fe(III) reduction in aquatic sediments
AU: Roden,-E.E.; Lovley,-D.R.*
AF: Water Resour. Div., 430 Natl. Cent., USGS, Reston, VA 22092, USA
SO: GEOMICROBIOL.-J. 1993 vol. 11, no. 1, pp. 49-56
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The potential utility of  super(55)Fe as a tracer for Fe(III) reduction in aquatic sediments was evaluated using freshwater sediments from the Potomac River, Md, in which Fe(III) reduction was the predominant terminal electron accepting process. In laboratory incubations of sediments amended with poorly crystalline  super(55)Fe(III) oxide, the accumulation of  super(55)Fe in Fe(II) over time paralleled Fe(II) production. However, within 1 h of addition of  super(55)Fe(III) oxide, significant quantities of  super(55)Fe were recovered in extractable (1 M sodium acetate, pH 5) and soluble Fe(II) pools. There was proportionately more  super(55)Fe(II) activity in sediments with higher Fe(II) concentrations. These results suggest that there was rapid isotopic exchange between  super(55)Fe in poorly crystalline Fe(III) oxide and the Fe(II) pools. Because of this exchange,  super(55)Fe could not be used to trace Fe(III) reduction in sediments in the manner that  super(35)SO sub(4) super(2-) is used to trace sulfate reduction. Although accumulation of  super(55)Fe in Fe(II) pools paralleled unlabeled Fe(II) production, given the relative ease with which Fe(II) pools in sediments can be measured there is no apparent advantage to using  super(55)Fe to follow Fe(III) reduction.
AN: 3530925

                                                                    661 of 1521  
TI: Fluorescence of dissolved organic matter: A comparison of North Pacific and North Atlantic Oceans during April 1991
AU: Hoge,-F.E.; Swift,-R.N.; Yungel,-J.K.; Vodacek,-A.
AF: Goddard Space Flight Cent., Wallops Flight Facil., Wallops I., VA, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1993 vol. 98, no. C12, pp. 22779-22787
LA: English
ER: M (Marine)
AB: Profiles of airborne-laser-induced fluorescence emission from dissolved organic matter in the upper ocean have been produced and compared for the Southern California Bight (SCB) and the Mid-Atlantic Bight (MAB). Findings were as follows. (1) The fluorescent components of dissolved organic matter (FDOM) are present in easily measurable quantities from near shore to well over 300 km offshore in the SCB and are likewise easily measurable in the coastal, shelf, slope, and Gulf Stream waters of the MAB. (2) The range of FDOM in the MAB is considerably greater than that in the SCB. (3) The lowest FDOM levels observed in the SCB were higher than those found in the Gulf Stream. (4) The onshore-to-offshore spatial gradient of the FDOM was found to be considerably lower in the SCB than in the MAB, with the highest levels of FDOM being found immediately adjacent to the coast in the MAB. This suggests that the water adjacent to the SCB shoreline is not as strongly influenced by terrestrial and estuarine sources of FDOM as the MAB is. (5) The spatial distribution of the FDOM within both the SCB and the MAB is frequently coherent with the spatial distribution of chlorophyll determined from the concurrent airborne-laser-induced phytoplankton pigment fluorescence measurements. However, distinct noncoherency is sometimes observed, especially at water mass boundaries.
AN: 3529532

                                                                    662 of 1521  
TI: Salt-marsh processes: A review
AU: Vernberg,-F.J.
AF: Belle W. Baruch Inst. Mar. Biol. and Coast. Res., Univ. South Carolina, Columbia, SC 29208, USA
SO: ENVIRON.-TOXICOL.-CHEM. 1993 vol. 12, no. 12, pp. 2167-2193
LA: English
ER: M (Marine); B (Brackish)
AB: Salt marshes are found between the high tide and the near-shore sublittoral zones along the coasts and up estuaries of continents, primarily in the temperate zone. They flourish in regions where much silt is carried to the coastal regions by rivers or where geological processes favor erosion and suspension of silt. Salt marshes have multiple ecological and economic values. They have a high rate of primary productivity; provide habitats for many marine species (including commercially important organisms); assist in flood and erosion control; lessen the effects of stormwater surges; and improve water quality by filtering pollutants, excess nutrients, and disease-causing microorganisms. In addition, this habitat is used for recreational and educational purposes by millions of people who spend millions of dollars. Although the myriad functions and uses of this habitat attest to its tremendous importance, legal protection of salt marshes varies significantly throughout the world. Salt-marsh processes are governed by the interactions between "natural" physical, chemical, geological, and biological factors. Of importance to ecotoxicologists and other scientists is understanding the intimate interaction between these various abiotic and biotic factors. This paper reviews the functional processes of salt marshes and discusses recent research advances under the following major headings: (a) physical, geological, and chemical factors; (b) biotic factors (including productivity of vascular plants, phytoplankton, epibenthic algae, and attached macrophytes; secondary production of primary and secondary consumers; and decomposition; (c) material cycling, biogeochemical cycling, and nutrients; (d) long-term changes; and (e) interaction with adjacent ecosystems.
AN: 3529432

                                                                    663 of 1521  
TI: Attraction of deep-sea amphipods to macrophyte food falls
AU: Lawson,-G.S.; Tyler,-P.A.; Young,-C.M.
AF: Dep. Oceanogr., Univ. Southampton, SO9 5NH, UK
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1993 vol. 169, no. 1, pp. 33-39
LA: English
ER: M (Marine)
AB: Traps baited with plant remains, either Thalassia or Sargassum, were deployed for 30 h on the seabed at depths of 500 and 10 m in the Bahamas. On retrieval, the deep traps had been colonised by three species of amphipod whilst inert controls (traps containing black plastic bags) had attracted only a single specimen of a fourth species. These data suggest that amphipods are attracted to plant debris as food rather than as shelter. Significantly more amphipods were attracted at the deepwater site than at the shallow site. We suggest that algal/seagrass foodfalls are a significant pathway by which energy enters the deep-sea and will be colonised rapidly by deepwater invertebrates.
AN: 3527541

                                                                    664 of 1521  
TI: Tropical marine ecosystems: The microbial component
AU: Chandramohan,-D.
AF: NIO, Dona Paula, Goa 403 004, India
SO: TROPICAL-ECOSYSTEMS:-ECOLOGY-AND-MANAGEMENT. Singh,-K.P.;Singh,-J.S.-eds. DELHI-INDIA WILEY-EASTERN 1992 pp. 241-254
LA: English
ER: M (Marine)
AB: Microbes such as bacteria, fungi and unicellular algae assume greater importance in the tropical marine ecosystems because of their abundance, biomass and activity in a number of chemical and biological processes that provide the driving force for vital biogeochemical cycles. Although the bacteriology of fish has been extensively studied in connection with spoilage, comparatively little work has been done on the role of intestinal flora in fish nutrition. A number of plant and animal diseases have been recognised. Of late isolation of human pathogens from coastal areas has become very common. Many marine microbes have been reported to produce a variety of bioactive compounds. An attempt has been made in this paper to give an overview of the work done in India.
AN: 3527068

                                                                    665 of 1521  
TI: Processes of biogeochemical matter cycle under the conditions of artificial eutrophication
AU: Punning,-J.-M.; Sagris,-A.
AF: Inst. Ecol., Est. Acad. Sci., Kevade St. 2, EE-0031 Tallinn, Estonia
SO: PROC.-ESTON.-ACAD.-SCI.-ECOL. 1993 vol. 3, no. 3, pp. 120-136
LA: English
ER: F (Freshwater)
AB: During the last decades a huge amount of different wastes has accumulated in the lakes in NE Estonia, In order to plan measures for improving the condition of the lakes, it is necessary to understand the mechanisms of processes taking place in the water--sediment boundary. The experiments conducted under the conditions of artificial eutrophication (fertilizers were added to microcosms) showed the existence of different mechanisms of matter cycle. The nutrients introduced during the phase of accelerating growth become immediately involved in the process of photosynthesis. This brings about a rapid increase in the oxygen content, a decrease in water transparency, coagulation, sorption, and destruction of substances. When nutrients are added during the deceleration phase of phytoplankton growth, the nutrients, that are mainly in an inorganic form, are deposited to the bottom from where they are transported back into the euphotic zone during the stagnation and vernal isothermia.
AN: 3526563

                                                                    666 of 1521  
TI: Influence of enhanced CO sub(2) on growth and photosynthesis of the red algae Gracilaria sp. and Gracilaria chilensis
AU: Gao,-K.; Aruga,-Y.; Asada,-K.; Kiyohara,-M.
AF: Hawaii Nat. Energy Inst., 2540 Dole St., Honolulu, HI 96822, USA
SO: J.-APPL.-PHYCOL. 1993 vol. 5, no. 6, pp. 563-571
LA: English
ER: M (Marine)
AB: The influence of elevated CO sub(2) concentrations on growth and photosynthesis of Gracilaria sp. and Gracilaria chilensis was investigated in order to procure information on the effective utilization of CO sub(2). Growth of both was enhanced by CO sub(2) enrichment (air + 650 ppm CO sub(2), air + 1250 ppm CO sub(2)), the enhancement being greater in Gracilaria sp. Both species increased uptake of NO sub(3) super(-) with CO sub(2) enrichment. Photosynthetic inorganic carbon uptake was depressed in Gracilaria chilensis by pre-culture (15 days) with CO sub(2) enrichment, but little affected in Gracilaria sp. Mass spectrometric analysis showed that O sub(2) uptake was higher in the light than in the dark for both species and in both cases was higher in Gracilaria sp. The higher growth enhancement in Gracilaria sp. was attributed to greater depression of photorespiration by the enrichment of CO sub(2) in culture.
AN: 3526524

                                                                    667 of 1521  
TI: Effects of methylated, organic, and inorganic substrates on microbial consumption of dimethyl sulfide in estuarine waters
AU: Wolfe,-G.V.; Kiene,-R.P.
AF: Coll. Oceanic Atmos. Sci., Oceanogr. Admin. Build. 104, Oregon State Univ., Corvallis, OR 97331-5503, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1993 vol. 59, no. 8, pp. 2723-2726
LA: English
ER: M (Marine)
AB: We examined the effects of a variety of amendments on the consumption of  (U- super(14)C) dimethyl sulfide in a Georgia salt marsh. Methylated compounds, particularly those with dimethyl groups, significantly inhibited dimethyl sulfide consumption, while nonmethylated substrates had little effect. Dimethyl disulfide and dimethyl ether were the most effective inhibitors tested.
AN: 3525922

                                                                    668 of 1521  
TI: Seasonal benthic microbial activity in the southern North Sea; oxygen uptake and sulphate reduction
AU: Upton,-A.C.; Nedwell,-D.B.*; Parkes,-R.J.; Harvey,-S.M.
AF: Univ. Essex, Dep. Biol., Wivenhoe Park, Colchester, CO4 3SQ, UK
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 101, no. 3, pp. 273-281
LA: English
ER: M (Marine)
AB: From an initial cruise, 6 sites were selected from the 41 sampled to be representative of the major types of sediment in the southern North Sea. The 6 sites in the mixed, frontal and stratified areas of the southern half of the North Sea exhibited a wide range of environmental conditions, particularly sediment type, water depth and organic matter content. Benthic microbial activity, and its seasonal variability, were determined at bimonthly intervals from September 1988 to September 1989. The significance of aerobic and anaerobic respiration in the degradation of organic carbon was investigated by measuring the rate of oxygen uptake and sulphate reduction for each sediment. All sites showed significant rates of oxygen uptake (range 5.3 to 27.8 mmol O sub(2) m super(-2)/d) and sulphate reduction (range 0.05 to 11.8 mmol SO sub(4) m super(-2)/d), and hence of organic matter mineralization. Aerobic respiration accounted for between 47 and 89% of annual organic matter degradation depending on the site, the balance being due to anaerobic sulphate reduction. Benthic mineralisation rates were greatest at a station near the Dogger Bank and one near the Dutch/Belgian coast. However, benthic mineralisation as a proportion of the net annual primary production in the water column was higher at stratified stations in the central North Sea (average 47%) than in the more southerly stations with mixed water columns (average 26%). Estimates of benthic organic mineralisation were used to calculate the magnitude of total benthic mineralisation in the southern half of the North Sea and compared to estimates of net primary production for the same area.
AN: 3524690

                                                                    669 of 1521  
TI: Arsenic in marine environment. Biogeochemistry and ecotoxicology.
OT: L'arsenic en milieu marin. Biogeochimie and ecotoxicologie
AU: Michel,-P.
AF: IFREMER, Cent. Nantes, BP 1049, 44037 Nantes Cedex, France
SO: REPERES-OCEAN PLOUZANE-FRANCE IFREMER-CENTRE-BREST,-SERVICES-DES-EDITIONS 1993 no. 4, 62 pp
LA: French
ER: M (Marine)
AB: Arsenic levels of in the marine environment are high in comparison with other contaminants. Over the past twenty years, a large number of arsenic organic compounds have been identified in the water, sediments and living species. This document constitutes a synthesis of current knowledge on arsenic sources, and contamination levels, on its biogeochemical cycle as well as its toxic effects on human and marine fauna. This paper highlights in particular the effects of phosynthesis on arsenic speciation and its distribution throughout the marine environment. Problems of toxicity in the case of certain phyto- and zooplankton species are identified. Bioaccumulation in seaweeds, molluscs and fishes is documented as well, with special attention to the species encountered in the French coastal waters.
AN: 3523900

                                                                    670 of 1521  
TI: Biogeochemical cycling of metals in freshwater algae from Manaus and Carajas, Brazil
AU: Konhauser,-K.O.; Fyfe,-W.S.
AF: Dep. Geol., Univ. Western Ontario, London, ON N6A 5B7, Canada
SO: ENERGY-SOURCES 1993 vol. 15, no. 4, pp. 595-608
LA: English
ER: F (Freshwater)
AB: Freshwater algae were analyzed in different riverine environments in Manaus and Carajas, Brazil. Filamentous algae from both locations were characterized by enhanced levels of a wide array of heavy metals. A comparison of the two main rivers in the Manaus area indicated that the algal samples from the solute-rich waters of the Rio Solimoes consistently contained higher metal concentrations than in the solute-deficient waters of the Rio Negro. A similar relationship also existed between algal samples collected from forested regions relative to adjacent deforested regions in the Carajas area. In the Rio Negro, diatoms were shown to be the most prolific eucaryotic micro-organisms found in the study area. These siliceous algae were found adhering to a variety of submerged solid substrates, including wood, rocks and leaves. The abundance of these unicellular micro-organisms that the dissolved silicon levels of the Rio Negro were influenced by biological activity.
AN: 3522804

                                                                    671 of 1521  
TI: The trace metal ecology of ichthyofauna in the Rockall Trough, North-eastern Atlantic
AU: Vas,-P.; Gordon,-J.D.M.; Fielden,-P.R.; Overnell,-J.
AF: Dep. Biol. Sci., Univ. Salford, Salford M5 4WT, UK
SO: MAR.-POLLUT.-BULL. 1993 vol. 26, no. 11, pp. 607-612
LA: English
ER: M (Marine)
AB: The concentrations of Cu, Mn, and Ni in tissue samples from 230 fish from the Rockall Trough were determined by atomic absorption spectrophotometry. Concentrations of Cu, Mn and Ni were 0.02-23  mu /g, 0.02-6.5  mu g/g and 0.02-10  mu g/g respectively. Cu appeared to selectively accumulate in liver tissues while Mn accumulated in gill tissues. Ni was evenly distributed throughout all tissues examined. Concentrations of all three metals generally decreased with length. Inter-specific differences between teleosts were found to be related to differences in feeding behaviour. There was no apparent concentration of metals through the food chain from prey to sharks. Low concentrations of Cu, Mn and Ni were detected in the water column (Cu 86-103 ng/l, Mn < 75 ng/l, Ni 210-224 ng/l), suggesting that for sharks in the Rockall Trough, the uptake of metals from diet is of more importance than that from the water column. Metallothionein-like proteins were detected in liver samples from nine species of deep-water shark. Concentrations were similar in all species (8-10  mu g/g) and were independent of hepatic Cu and Cd. It is suggested that these proteins are involved in the homeostasis of essential trace metals.
AN: 3522557

                                                                    672 of 1521  
TI: Deposition and fate of trace metals in our environment. Symposium proceedings. Held in Philadelphia, Pennsylvania on October 8, 1991
AU: Verry,-E.S.; Vermette,-S.J.
CA: North Cent. Forest Experiment Stn., St. Paul, MN (USA)
SO: GEN.-TECH.-REP.-USDA-FOR.-SERV.-N.-CENT.-FOR.-EXP.-STN. 1992 174 pp
RN: FSGTR-NC-150 (FSGTRNC150)
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: On October 8, 1991, in Philadelphia, the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) Technical Committee hosted a symposium on the deposition and fate of trace metals in the environment. Fourteen papers were prepared by 37 authors with a breadth of experience in trace metal ecology over the last decade. The proceedings are meant to inform the members of the analytic and collection methods for trace metals in precipitation, and the processing of trace metals in the landscape and its biota. It is a solid review of trace metals designed to facilitate an informed discussion about the addition of trace metals to the NADP/NTN network.
AN: 3522519

                                                                    673 of 1521  
TI: An empirical analysis of the strength of phytoplankton-dimethylsulfide-cloud-climate feedback cycle
AU: Lawrence,-M.G.
AF: Max-Planck-Inst. Chem., Mainz, FRG
SO: J.-GEOPHYS.-RES.-D-ATOMS. 1993 vol. 98, no. D11, pp. 20663-20673
LA: English
ER: M (Marine)
AB: The possible influence of the marine biogeochemical sulfur cycle on the global climate has been a topic of much recent research. Based on the hypothesis that phytoplankton could affect cloud affect cloud albedo by producing dimethylsulfide, which is a precursor to aerosols and cloud condensation nuclei, and that cloud albedo could in turn affect the productivity of the phytoplankton, the presence of such a feedback cycle would have significant implications for models of global climate change. By considering available data on the relationships between individual components of the proposed feedback, an empirical model is developed of the cycle as a whole, allowing an assessment to be made of the degree to which the cycle could thermostatically regulate the climate. It is estimated that the feedback strength is about 20% (10%-50%) of that which would be necessary to completely counteract a perturbation to the global climate, such as is anticipated due to accumulation of anthropogenic greenhouse gases.
AN: 3522144

                                                                    674 of 1521  
TI: The distribution and biogeochemical cycling of mercury in the Equatorial Pacific Ocean
AU: Mason,-R.P.; Fitzgerald,-W.F.
AF: Ralph Parsons Lab., 48-108, MIT, Cambridge, MA 02139, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 9, pp. 1897-1924
LA: English
ER: M (Marine)
AB: The ocean is an important part of the global mercury (Hg) cycle, both as a source and sink for atmospheric Hg. This investigation was initiated to study the speciation and distribution of Hg in the equatorial Pacific Ocean. Monomethylmercury (MMHg) and dimethylmercury (DMHg) were found principally in the low oxygen sub-thermocline region, while elemental Hg (Hg super(o)) was found throughout the upper ocean. Flux calculations and modelling studies suggest that DMHg and MMHg are formed from reactive Hg (Hg sub(R)) primarily in the low oxygen region. Particulate dissolution is the major source of Hg to the low oxygen zone. DMHg probably decomposes into MMHg, and MMHg is further demethylated to Hg super(o). In the mixed layer, Hg super(o) is also formed via direct reduction of Hg sub(R). This investigation provides evidence that the rate of supply of Hg sub(R) controls the rate of formation of methylated Hg species and Hg super(o), and that competition between these processes determines the speciation and distribution of Hg in the upper ocean of the equatorial Pacific.
AN: 3520083

                                                                    675 of 1521  
TI: Application of a generalized scavenging model to time series  super(234)Th and particle data obtained during the JGOFS North Atlantic Bloom Experiment
AU: Clegg,-S.L.; Whitfield,-M.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 8, pp. 1529-1545
LA: English
ER: M (Marine)
AB: Primary production, particle concentration and flux data, obtained as part of the JGOFS North Atlantic Bloom Experiment, have been used to construct a self consistent, time dependent, particle cycle model for the upper water column for the period 25 April-30 May 1989. Daily  super(234)Th concentrations and fluxes are modelled over the course of the bloom, and the results compared with available data. Use of a single pseudo-first-order rate constant k sub(1)' for the adsorption of  super(234)Th onto particulate material in the model gives satisfactory agreement with measured  super(234)Th profiles. Modelled concentrations of  super(234)Th on large, sinking particles--which must be known in order to calculate particle fluxes from  super(234)Th disequilibrium-are predicted well by the model. The results also suggest that particle fluxes determined from sediment traps may be systematically low.
AN: 3519918

                                                                    676 of 1521  
TI: Nature, mass and preferential sites of coarse woody debris deposits in the lower Ain valley (Mollon Reach), France
AU: Piegay,-H.
AF: Cent. Rech. Geogr. et Amenage., Univ. Jean Moulin-Lyon 3, et URA 260 CNRS, 74 Rue Pasteur, BP0638, 69239 Lyon Cedex 02, France
SO: REGUL.-RIVERS:-RES.-MANAGE. 1993 vol. 8, no. 4, pp. 359-372
LA: English
ER: F (Freshwater)
AB: Coarse woody debris (CWD) has been examined in a section of the Ain, a sixth order piedmont river with an actively meandering channel and a wooded floodplain. The spatial distribution of CWD, its mass and forms of accumulation are controlled by the hydrodynamics and the retention capacity of the forest. A typology shows the relative importance of woody debris in the mosaic of patches and the essential role of the ecotonal zones. The mass of debris varies from 0.001 t/ha to more than 200 t/ha, but is lower than those observed in certain American rivers. Most of the material is deposited in the margins and forms a narrow debris line. The restocking in woody debris is recent in Europe and tends to diversify the environment. This affects the researcher and the planner. The first considers this transit of material as a useful hydromorphodynamic and biodynamic tool which is easy to evaluate, and the second considers it as a restoring and generative vector, the ecological functions of which are recognized. Its effect is stronger today as the watershed area tends to be subjected to a decrease in agricultural activity.
AN: 3519549

                                                                    677 of 1521  
TI: A simple heuristic model of nutrient cycling in an estuary
AU: Kimmerer,-W.J.; Smith,-S.V.; Hollibaugh,-J.T.
AF: BioSystems Analysis Inc., 3152 Paradise Dr., Tiburon, CA 94920, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1993 vol. 37, no. 2, pp. 145-159
LA: English
ER: B (Brackish)
AB: Three decades of discussion and study have not resolved the apparent discrepancy between N-limitation of primary production and the ability of marine ecosystems to fix N. We use a simple model as a heuristic tool to examine controls on nutrient cycling in a shallow estuary, with Tomales Bay, California as the prototype. The model is a steady-state, one-box model with inputs and losses of nutrients and organic matter, and terms representing N-fixation and denitrification. The physical description of the system is deliberately kept simple to permit a focus on the key biogeochemical reactions. Growth of autotrophs in the model can be limited either by dissolved inorganic nitrogen (DIN) or dissolved inorganic phosphorus (DIP). Nitrogen-fixation is controlled by the availability of DIP or limited by excess amounts of DIN. Model results demonstrate that, for a system with a long residence time, autotroph biomass and total organic matter are controlled primarily by the rate of delivery of P to the system, either as DIP or in organic matter. Increasing the delivery rate of DIN raises autotroph biomass slightly but has little effect on total organic matter. This is because the rates of input of P as DIP or organic matter control the N-fixation rate, and denitrification limits the build-up of DIN in the system. Thus, denitrification and N-fixation act as opposing negative feedbacks, insuring that the supply of N remains roughly commensurate with that of P. When exchange with the ocean is increased, reducing residence time, the relative importance of DIN input increases relative to that of DIP.
AN: 3518700

                                                                    678 of 1521  
TI: Past and present cycle of carbon on our planet
AU: Schlegel,-H.G.
AF: Inst. Mikrobiol., Georg-August-Univ., Grisebachstr. 8, W-3400 Goettingen, FRG
SO: FEMS-MICROBIOL.-REV. 1992 vol. 103, no. 2-4, pp. 347-354
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 3518691

                                                                    679 of 1521  
TI: Land and water interface zones
AU: Downing,-J.P.; Meybeck,-M.; Orr,-J.C.; Twilley,-R.R.; Scharpenseel,-H.-W.
AF: Pac. Northwest Lab., Mar. Sci. Lab., 1529 W. Sequim Bay Road, Sequim, WA 98382, USA
CO: Int. Workshop on Terrestrial Biospheric Carbon Fluxes: Quantification of Sinks and Sources of CO sub(2), Bad Harzburg (FRG), 1-5 Mar 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1993 vol. 70, no. 1-4, pp. 123-137
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This paper reports analyses of C pools and fluxes in land-water interface zones completed at the International Workshop: Terrestrial Biospheric Carbon Fluxes; Quantification of Sinks and Sources of CO sub(2) (Bad Harzburg, Germany, March 1-5, 1993). The objective was to determine the role of these zones as global sinks of atmospheric CO sub(2) as part of a larger effort to quantify global C sinks and sources in the past (ca. 1850), the present, and the foreseeable future (ca. 2050). Assuming the world population doubles by the year 2050, storage of atmospheric C in reservoirs will also double, as will river loads of atmospheric C and nutrients. It is estimated that C sinks in temperate and boreal wetlands have decreased by about 50%, from 0.2 to 0.1 Gt C/yr, since 1850. The total decrease for wetlands may be considerably larger when tropical wetlands are taken into account, however, the area and C density of tropical wetlands are not well known at this time. Changes in cultivation practices and improved sampling of methaneogenesis have caused estimates of CH sub(4) emissions from ricelands to drop substantially from 150 to 60 Tg yr super(-1). Even with doubled N and P loads, rivers are unlikely to fertilize more than about 20% of the new primary production in the coastal ocean. The source of C for this new production may not be the atmosphere, however, because the coastal ocean exchanges large quantities of DIC with the open ocean. Until the C fluxes from air-sea exchange of CO sub(2) and DIC are better quantified, the C-sink potential of the coastal ocean will remain a major uncertainty in the global C cycle. Analysis of model simulations of oceanic C uptake reconfirmed that the open ocean appears to take up about 2.0 Gt C/yr from the atmosphere and that model estimates are in better accord now,  plus or minus 0.5 Gt C/yr, than ever before.
AN: 3518538

                                                                    680 of 1521  
TI: Modification of the biogeochemical cycle of silica with eutrophication
AU: Conley,-D.J.; Schelske,-C.L.; Stoermer,-E.F.
AF: Horn Point Environ. Lab. Cent. Environ. and Estuar. Stud., Univ. Maryland Syst., P.O. Box 775, Cambridge, MD 21613, USA
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 101, no. 1-2, pp. 179-192
LA: English
ER: M (Marine); F (Freshwater)
AB: The response of aquatic systems to additions of N and P is generally to increase algal biomass. The partitioning of these nutrients into different functional groups of autotrophic organisms is dependent upon both intrinsic and extrinsic factors. A common response to nutrient loading in northern temperate aquatic ecosystems is an increase in diatom biomass. Because nutrient enrichment generally leads to increases in water column concentrations of total N and total P (and not Si) such nutrient loading can lead to transient nutrient limitation of diatom biomass due to lack of dissolved silicate (DSi). Increased production of diatom biomass can lead to an increased accumulation of biogenic silica in sediments, ultimately resulting in a decline in the water column reservoir of DSi. Such biogeochemical changes in the silica cycle induced by eutrophication were first reported for the North American Laurentian Great Lakes. However, these changes are not a regional problem confined to the Great Lakes, but occur in many freshwater and marine systems throughout the world. Here we summarize the effects of anthropogenic modification of silica biogeochemical cycles for the North American Laurentian Great Lakes, describe some of the biogeochemical changes occurring in other systems, and discuss some of the ecological implications of a reduction in water column DSi concentrations, including changes in species composition, as DSi concentrations become limiting to diatom growth and biomass, changes in food web dynamics, and altered nutrient-recycling processes.
AN: 3517119

                                                                    681 of 1521  
TI: Design and application of rRNA-targeted oligonucleotide probes for the dissimilatory iron- and manganese-reducing bacterium Shewanella putrefaciens
AU: DiChristina,-T.J.; DeLong,-E.F.
AF: Biol. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1993 vol. 59, no. 12, pp. 4152-4160
LA: English
ER: F (Freshwater)
AB: A 16S rRNA-targeted oligonucleotide probe specific for the iron (Fe super(3+))- and manganese (Mn super(4+))-reducing bacterium Shewanella putrefaciens was constructed and tested in both laboratory- and field-based hybridization experiments. The radioactively labeled probe was used to detect S. putrefaciens in field samples collected from the water column and sediments of Oneida Lake in New York and its major southern tributary, Chittenango Creek. S. putrefaciens was quantified by (i) hybridization of the probe to bulk DNA extracted from field samples and normalization of the S. putrefaciens-specific rRNA to total eubacterial rRNA, (ii) a colony-based probe hybridization assay, and (iii) a colony-based biochemical assay which detected the formation of iron sulfide precipitates on triple-sugar iron agar. The results of field applications indicated that the three detection methods were comparable in sensitivity for detecting S. putrefaciens in water column and sediment samples. S. putrefaciens rRNA was detected in the surficial layers of the lake and creek sediments, but the levels of S. putrefaciens rRNA were below the detection limits in the lake and creek water samples. The highest concentrations of S. putrefaciens rRNA, corresponding to approximately 2% of the total eubacterial rRNA, were detected in the surficial sediments of Chittenango Creek and at a midlake site where the Oneida Lake floor is covered by a high concentration of ferromanganese nodules. This finding supports the hypothesis that metal-reducing bacteria such as S. putrefaciens are important components in the overall biogeochemical cycling of iron, manganese and other elements in seasonally anoxic freshwater basins.
AN: 3516514

                                                                    682 of 1521  
TI: On the distribution of dissolved hydrocarbons in natural water
AU: Yunker,-M.B.; Cretney,-W.J.; Fowler,-B.R.; Macdonald,-R.W.; McLaughlin,-F.A.; Whitehouse,-B.G.
AF: Royal Roads Military Coll., FMO, Victoria, BC V0S 1B0, Canada
SO: ORG.-GEOCHEM. 1991 vol. 17, no. 3, pp. 301-307
LA: English
ER: F (Freshwater)
AB: The identity and form of dissolved organic matter in rivers and oceans are fundamental to the biogeochemical cycle of carbon. In particular, understanding the phase distribution of hydrocarbon compounds is a prerequisite to predicting the transfer between phases and the impact of anthropogenic inputs of fossil fuels to the aquatic environment. After rigorous blank-correction of each individual hydrocarbon component of dissolved and particulate hydrocarbon samples from the Mackenzie River, we obtained dissolved hydrocarbon measurements that were unquestionably above the mean blank. Equivalence of the dissolved and particulate hydrocarbon compositions indicates that the two fractions are coupled or at equilibrium in natural waters. Changes in individual hydrocarbon concentrations with sample volume suggest that the dissolved hydrocarbons may be distributed fractally in water.
AN: 3515198

                                                                    683 of 1521  
TI: Genetic analysis of the marine manganese-oxidizing Bacillus sp. strain SG-1: Protoplast transformation, Tn917 mutagenesis, and identification of chromosomal loci involved in manganese oxidation
AU: Van-Waasbergen,-L.G.; Hoch,-J.A.; Tebo,-B.M.*
AF: Mar. Biol. Res. Div., Scripps Inst. Oceanogr., Univ. California-San Diego, La Jolla, CA 92093, USA
SO: J.-BACTERIOL. 1993 vol. 175, no. 23, pp. 7594-7603
LA: English
ER: M (Marine)
AB: Mature spores of the marine Bacillus sp. strain SG-1 bind and oxidize manganese(II), thereby becoming encrusted with a manganese(IV) oxide. Both the function and mechanism of this oxidation are unknown, although evidence suggests that spore coat proteins are involved. To further study this phenomenon, methods of genetic analysis were developed for SG-1. By a modified protoplast transformation procedure, SG-1 was transformed ( similar to 100 transformants per  mu g of DNA) with several different plasmids of gram-positive origin. Transposon Tn917, delivered on the temperature-sensitive plasmid pLTV1, was used to generate mutants of SG-1. Conditions were established that allowed 98% plasmid loss and insertions to be recovered at a frequency of 10 super(-3). Each mutant was found to be the result of a single insertion event. Restriction analysis of 27 mutants that do not oxidize manganese but still sporulate localized 17 of the insertions within two regions of the chromosome (termed Mnx regions), and a physical map of these regions was generated. Analysis of 18 transposon integrants in which manganese oxidation was unaffected revealed random transposon integration, with none of their insertions mapping within the Mnx regions. The Mnx regions were cloned from wild-type SG-1, and the largest region, carried on the lactococcal plasmid pGK13, was used to complement in trans one of the nonoxidizing mutants. The results demonstrate that the Mnx regions encode factors that are required for the oxidation of manganese, and this represents the first report identifying genes involved in bacterial manganese oxidation.
AN: 3514455

                                                                    684 of 1521  
TI: Nutrient release from crayfish, and its potential impact on primary production in lakes
AU: Hessen,-D.O.; Kristiansen,-G.; Skurdal,-J.
AF: Norwegian Inst. Water Res., Box 69 Korsvoll, N-0808 Oslo 8, Norway
CO: 9. Int. Symp. of Astacology, Reading, Barkshire (UK), 5-10 Apr 1992
SO: FRESHWATER-CRAYFISH-IX. Holdich,-D.M.;Warner,-G.F.-eds. LAFAYETTE,-LA-USA UNIVERSITY-OF-SOUTHWESTERN-LOUISIANA 1993 pp. 311-317
LA: English
ER: F (Freshwater)
AB: The potential effect of nitrogen (N) and phosphorus (P) release from noble crayfish, Astacus astacus (L.), on phytoplankton production was assessed by combining experimental data on total release and crayfish density calculations in mesotrophic Lake Steinsfjorden. While the crayfish has a substantial release of dissolved nitrogen, there is a low specific release of P compared to other aquatic organisms. The maximum potential phytoplankton yield sustained by nutrient release from crayfish in this lake would not exceed an equivalent of 1.4 mg C m super(-2)/d, which was less than 1% of measured primary production of the lake. It may be concluded that zooplankton and fish are far more important for the nutrient cycling of the lake. While these pelagic components of the aquatic food web are important both as consumers and remineralizers, the role of crayfish is primarily to process dead organic matter.
AN: 3514349

                                                                    685 of 1521  
TI: Digestive enzyme activity as a quantitative measure of protistan grazing: The acid lysozyme assay for bacterivory
AU: Gonzalez,-J.M.; Sherr,-B.F.; Sherr,-E.B.
AF: Japan Mar. Sci. and Technol. Cent., 2-15 Natsushima-cho, Yokosuka 237, Japan
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 100, no. 1-2, pp. 197-206
NT: Bibliogr.: 50 ref.
LA: English
ER: M (Marine)
AB: Lysozyme specifically degrades peptidoglycan, a major structural component of prokaryotic cell walls. The basis of the method is determination of lysozyme activity present in protistan food vacuoles by using a fluorochrome-linked artificial substrate, 4-methylumbelliferyl  beta -D-N,N',N"-triacetylchitotriose (MUF- (GlcNAc)  sub(3)) as an analogue of peptidoglycan. Measurement of rate of MUF cleavage from the substrate in sonicated samples at acid pH (4.5) distinguishes activity of digestive enzymes present in protistan food vacuoles from extracellular or intracytoplasmic lysozyme activity. Acid lysozyme activity was calibrated against rate of bacterivory estimated using the fluorescently labeled bacteria (FLB) uptake method. Results from the 2 methods were significantly correlated (r super(2) = 0.98) for both cultures of bacterivorous protists and for estuarine and nearshore seawater samples, over a wide range of rates of bacterivory (10 super(3) to 10 super(6) bacteria ml super(-1) h super(-1)). The relation between the 2 variables determined from water samples taken in open North Pacific gyre water had a higher slope compared to that of the other samples.
AN: 3512333

                                                                    686 of 1521  
TI: An introduction to the biogeochemical cycling of calcium and substitutive strontium in living coral reef mesocosms
AU: Lang,-G.T.
AF: Environ. Sci., P.O. Box 409, Cochranton, PA 16314, USA
SO: ZOO-BIOL. 1993 vol. 12, no. 5, pp. 425-433
NT: Special issue: Aquariums.
LA: English
ER: M (Marine)
AB: The coral reef mesocosms designed by the Smithsonian Institution's Dr. Walter Adey, his Marine System Laboratory personnel, and staff members of the Pittsburgh Aqua-Zoo simulate most of the physical, chemical, and biological parameters found in natural Caribbean coral reefs. After developing the mesocosm in Pittsburgh, an evaluation and comparison between natural reef seawater sources and closed mesocosm seawater conditions indicated that an additional parameter should be investigated. It was hypothesized that, given time, the aragonite- and calcite (CaCO sub(3) crystal forms)-producing organisms in the closed mesocosms could deplete the seawater of available Ca super(2+) and substitutive Sr super(2+). Atomic absorption spectrophotometry was utilized to determine concentrations in the seawater over time. Results showed a substantial reduction in dissolved Ca and Sr in the mesocosm after approximately two years. Dissolved aragonitic Halimeda algae parts were put into the system for replacive purposes. In terms of the biogeochemical cycling of Ca super(2+) and Sr super(2+), the coral reef mesocosm organisms behaved similarly to natural reefs, which have a constant supply of dissolved Ca super(2+) and Sr super(2+). Further research utilizing radiolabeled sources of Ca super(2+), Sr super(2+), and Mg super(2+), in conjunction with in vivo scanning electron microscopy (SEM) and growth increment studies, are recommended for determining the exact biogeochemical pathways for these elements in coral reefs, and to quantify growth parameters.
AN: 3512258

                                                                    687 of 1521  
TI: Accord between ocean models predicting uptake of anthropogenic CO sub(2)
AU: Orr,-J.C.
AF: Lab. Modelisation Climat. Environ., DSM/CEN Saclay/CEA, L'Orme Merisiers, Bat. 709, F-91191 Gif-sur-Yvette, France
CO: Int. Workshop on Terrestrial Biospheric Carbon Fluxes: Quantification of Sinks and Sources of CO sub(2), Bad Harzburg (FRG), 1-5 Mar 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1993 vol. 70, no. 1-4, pp. 465-481
LA: English
ER: M (Marine)
AB: Models of the ocean provide the best estimate of how much anthropogenic CO sub(2) the ocean can and will absorb. Yet their agreement is only within 40% as characterized by the range of 2.0  plus or minus  0.8 Gt C/yr computed by the Intergovernmental Panel on Climate Change (IPCC) in 1990 from four model estimates. Since then, one of the former results has been updated and two new model estimates have become available. In a reassessment, now with six ocean models and concern for individual model uncertainties, this study found a narrower range of 2.0  plus or minus  0.5 Gt C/yr (38% less than the former uncertainty). Less uncertainty for oceanic uptake of anthropogenic CO sub(2), means greater certainty for two combined terms in the budget for the global carbon cycle. First the uncertainty of the combined atmosphere plus ocean sink is also nearly halved (now at  plus or minus  0.5 Gt C/yr for 1980-1989). Second, the uncertainty of the imbalance term (or missing sink) is reduced, but only slightly because most of its large uncertainty remains associated with the difficulty in precisely quantifying deforestation and land use change.
AN: 3509485

                                                                    688 of 1521  
TI: Benthic bacterial production and nutrient sediment-water exchange in sandy North Sea sediments
AU: Van-Duyl,-F.C.; Van-Raaphorst,-W.; Kop,-A.J.
AF: Netherlands Inst. Sea Res. (NIOZ), P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 100, no. 1-2, pp. 85-95
NT: Bibliogr.: 69 ref.
LA: English
ER: M (Marine)
AB: The relationship between benthic bacterial production and biomass and sediment-water exchange rates of inorganic nutrients was examined in the North Sea (Dogger Bank region), in summer. The sediments were sandy, poor in organic matter and with low buffering capacities for nutrients. Fluxes of dissolved inorganic N (DIN) and P (DIP) across the sediment-water interface were measured using undisturbed sediment cores. Bacterial production ( super(3)H-thymidine incorporation method) in the sediment surface layer and bacterial biomass were analysed in the same sediment. By comparison of the benthic activities at 13 stations we assessed significant negative relations between bacterial production and sediment-water fluxes of nutrients. With increasing bacterial production the net efflux of DIN and DIP decreased. Bacterial production was significantly related to bacterial biomass and bacterial biomass was significantly related to chlorophyll a and pheopigment in the sediment, suggesting that enhanced bacterial production rates were associated with input of organic carbon.
AN: 3507956

                                                                    689 of 1521  
TI: New and regenerated production in relation to the microbial loop in the NW Mediterranean Sea
AU: Selmer,-J.-S.; Ferrier-Pages,-C.; Cellario,-C.; Rassoulzadegan,-F.
AF: Dep. Gen. and Mar. Microbiol., Univ. Goeteborg, Carl Skottsbergs Gata 22, S-413 19 Goeteborg, Sweden
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 100, no. 1-2, pp. 71-83
NT: Bibliogr.: 71 ref.
LA: English
ER: M (Marine)
AB: Nitrogen transformations were investigated in the Bay of Villefranche-sur-Mer, on the south coast of France, during autumn 1990 and spring 1991, using  super(15)N-isotope techniques on size-fractionated sea water samples. Besides measuring uptake of ammonium and nitrate, and ammonium regeneration, the biological composition in 4 size fractions (< 1  mu m, <10  mu m, <100  mu m and unfractionated water) was determined. The plankton was dominated by pico- and nanoplankton, of which the cyanobacteria and nanoflagellates dominated the autotrophs. Heterotrophic bacteria constituted 70 and 30% of the <1  mu m and <10  mu m fractions, respectively. During spring, ammonium uptake rates were low and nitrate uptake rates often negligible, resulting in a total dominance (98 to 100%) of regenerated production. In autumn, however, nitrate uptake rates were higher, with new production amounting to 34%. The regenerated production was mostly accomplished by pico- and nanoplankton, especially cyanobacteria and autotrophic nanoflagellates, but also heterotrophic bacteria.
AN: 3507955

                                                                    690 of 1521  
TI: Production of organic and inorganic carbon within a large-scale coccolithophore bloom in the Northeast Atlantic Ocean
AU: Fernandez,-E.; Boyd,-P.; Holligan,-P.M.; Harbour,-D.S.
AF: Plymouth Mar. Lab., Prospect Pl., West Hoe, Plymouth PL1 3DH, UK
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 97, no. 3, pp. 271-285
NT: Bibliogr: 52 ref.
LA: English
ER: M (Marine)
AB: An extension bloom (250,000 km super(2)) of the coccolithophore Emiliania huxleyi developed in the northeast Atlantic in Jun 1991. At the time of the observations in late Jun, the centre of the bloom was characterised by low concentrations of chlorophyll a (< 1 mg m super(-3)) and particulate organic carbon (< 200 mg m super(-3)) and high particulate inorganic carbon (PIC) (> 300 mg m super(-3)) values. Photosynthesis-irradiance experiments carried out along the cruise track showed the existence of a negative exponential relationship between assimilation number (P super(B) sub(m) sub(a) sub(x)) and PIC. Significant rates of inorganic carbon incorporation were only measurable in surface waters at the periphery of the bloom and in subsurface waters north of 61 degree N. Calcification rates of up to 1.5 mg C m super(-3) h super(-1) were measured. In general, a direct relationship was found between calcification rates and P super(B) sub(m) sub(a) sub(x) or chlorophyll a-normalized photosynthesis. Calcification-irradiance curves revealed that significant amounts of carbon were incorporated into coccoliths in darkness and also that, on some occasions, calcification in subsurface populations saturated at higher irradiances than in surface ones. An empirical model based on the biomass of E. husleyi and Coccolithus pelagicus and the beam attenuation coefficient accounted for a large proportion (> 70%) of the variability in surface rates of calcification. Estimates of calcification rates derived from the model are consistent with previously reported data and compatible with the measured stocks of PIC and with the duration of the bloom as revealed by satellite imagery.
AN: 3507769

                                                                    691 of 1521  
TI: Project POSEIDON, the NODC on-line database
AU: Topoly,-P.J.
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 p. 393
NT: Summary only.
LA: English
ER: M (Marine)
AB: The U.S. National Oceanographic Data Center (NODC) has under development a relational database system for in-situ marine biogeochemical parameters. The system is intended to replace the mainframe-oriented NODC master files. The first phase of this development, Project POSEIDON, is being undertaken to demonstrate the capabilities and possibilities of such a system. POSEIDON has been developed using a client-server architecture consisting of DEX VAX cluster and a Teradata 700 data base engine. The relational model used to store, manage, and access data is a simple approach keyed to individual marine data parameters. Each parameter is keyed or linked to other parameters by a complex, yet straightforward, set of metadata. The POSEIDON database is not being implemented as an application, but rather as a fast powerful data supplier to other applications. A graphical user interface system, PEGASUS, is the link between the database and the user. This interface is being developed in three phases: an internal LAN version for NODC data management; a network version for Internet and dial-in access; and a stand-alone version for personal computers and workstations. The latter implementation, coupled with a POSEIDON database on a CD-ROM, will provide the climate researcher with a powerful, yet simple desktop tool. Beta testing of PEGASUS will begin in the Spring of 1992.
AN: 3506668

                                                                    692 of 1521  
TI: Automated in situ observations of upper ocean biogeochemistry, bio-optics, and physics and their potential use for global studies
AU: Dickey,-T.D.; Granata,-T.C.; Taupier-Letage,-I.
AF: Ocean Phys. Group, Univ. South. California, Dep. Geol. Sci., SCI 283, Los Angeles, CA 90089-0740, USA
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 317-355
LA: English
ER: M (Marine)
AB: The processes controlling the flux of carbon in the upper ocean have dynamic ranges in space and time of at least nine orders of magnitude. These processes depend on a broad suite of inter-related biogeochemical, bio-optical, and physical variables. These variables should be sampled on scales matching the relevant phenomena. Traditional ship-based sampling, while critical for detailed and more comprehensive observations, can span only limited portions of these ranges because of logistical and financial constraints. Further, remote observations from satellite platforms enable broad horizontal coverage which is restricted to the upper few meters of the ocean. For these main reasons, automated subsurface measurement systems are important for the fulfillment of research goals related to the regional and global estimation and modeling of time varying biogeochemical fluxes. Within the past few years, new sensors and systems capable of autonomously measuring several of the critical variables have been developed. The platforms for deploying these systems now include moorings and drifters and it is likely that autonomous underwater vehicles (AUV's) will become available for use in the future. Each of these platforms satisfies particular sampling needs and can be used to complement both shipboard and satellite observations. In this review, 1) sampling considerations are summarized, 2) examples of data obtained from some of the existing automated in situ sampling systems are highlighted, 3) future sensors and systems are discussed, 4) data management issues for present and future automated systems are considered, and 5) the status of near real-time data telemetry are outlined.
AN: 3506614

                                                                    693 of 1521  
TI: Ocean time-series near Bermuda: Hydrostation S and the U.S. JGOFS Bermuda Atlantic time-series study
AU: Michaels,-A.F.; Knap,-A.H.
AF: Bermuda Biol. Stn., Ferry Reach, St. Georges, Bermuda
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 295-316
LA: English
ER: M (Marine)
AB: Bermuda is the site of two ocean time-series programs. At Hydrostation S, the ongoing biweekly profiles of temperature, salinity and oxygen now span 37 years. This is one of the longest open-ocean time-series datasets and provides a view of decadal scale variability in ocean processes. In 1988, the U.S. JGOFS Bermuda Atlantic Time-series Study began a wide range of measurements at a frequency of 14-18 cruises each year to understand temporal variability in ocean biogeochemistry. On each cruise, the data range from chemical analyses of discrete water samples to data from electronic packages of hydrographic and optics sensors. In addition, a range of biological and geochemical rate measurements are conducted that integrate over time-periods of minutes to days. This sampling strategy yields a reasonable resolution of the major seasonal patterns and of decadal scale variability. The Sargasso Sea also has a variety of episodic production events on scales of days to weeks and these are only poorly resolved. In addition, there is a substantial amount of mesoscale variability in this region and some of the perceived temporal patterns are caused by the intersection of the biweekly sampling with the natural spatial variability. In the Bermuda time-series programs, the authors have added a series of additional cruises to begin to assess these other sources of variation and their impacts on the interpretation of the main time-series record. However, the adequate resolution of higher frequency temporal patterns will probably require the introduction of new sampling strategies and some emerging technologies such as biogeochemical moorings and autonomous underwater vehicles.
AN: 3506608

                                                                    694 of 1521  
TI: Data management for community research projects: A JGOFS case study
AU: Lowry,-R.K.
AF: Proudman Oceanogr. Lab., Bidston Obs., Bidston, Birkenhead, Merseyside L43 7RA, UK
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 251-273
LA: English
ER: M (Marine)
AB: Since the mid 1980s, much of the marine science research effort in the United Kingdom has been focused into large scale collaborative projects involving public sector laboratories and university departments, termed Community Research Projects. Two of these, the Biogeochemical Ocean Flux Study (BOFS), and the North Sea Project incorporated large scale data collection to underpin multidisciplinary modeling efforts. The challenge of providing project data sets to support the science was met by a small team within the British Oceanographic Data Centre (BODC) operating as a topical data centre. The role of the data centre was to both work up the data from the ship's sensors and to combine these data with sample measurements into on-line databases. The working up of the data was achived by a unique symbiosis between data centre staff and project scientists. The project management, programming and data processing skills of the data centre were combined with the oceanographic experience of the project communities to develop a system which has produced quality controlled, calibrated data sets from 49 research cruises in 3.5 years of operation. The data centre resources required to achieve this were modest and far outweighed by the time liberated in the scientific community by the removal of the data processing burden. However, projects covering a larger, even international scale could be successfully supported by a network of topical data centres managing online databases which are interconnected by object oriented distributed data management systems over wide area networks.
AN: 3506585

                                                                    695 of 1521  
TI: Data management for JGOFS: Theory and design
AU: Flierl,-G.R.; Bishop,-J.K.B.; Glover,-D.M.; Paranjpe,-S.
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 229-249
LA: English
ER: M (Marine)
AB: The Joint Global Ocean Flux Study (JGOFS), currently being organized under the auspices of the Scientific Committee for Ocean Research (SCOR), is intended to be a decade long internationally coordinated program. The main goal of JGOFS is to determine and understand on a global scale the processes controlling the time-varying fluxes of carbon and associated biogenic elements in the ocean and to evaluate the related exchanges with the atmosphere, sea floor and continental boundaries. A long-term goal of JGOFS will be to establish strategies for observating, on long time scales, changes in ocean biogeochemical cycles in relation to climate change. Participation from a large number of U.S. and foreign institutions is expected. JGOFS investigators have begun a set of time-series measurements and global surveys of a wide variety of biological, chemical and physical quantities, detailed process-oriented studies, satellite observations of ocean color and wind stress and modeling of the bio-geochemical processes. These experiments will generate data in amounts unprecedented in the biological and chemical communities; rapid and effortless of these data will be important to the success of JGOFS. The authors discuss the possibility for the user of a small computer connected to a network to be able to locate and work with data at NODC or indeed anywhere in a distributed data base without regards to its location or format.
AN: 3506576

                                                                    696 of 1521  
TI: The JGOFS North Atlantic Bloom Experiment: An overview
AU: Ducklow,-H.W.
AF: Horn Point Mar. Lab., Univ. Maryland, Cambridge, MD 21613, USA
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 205-227
LA: English
ER: M (Marine)
AB: The North Atlantic Bloom Experiment (NABE) of the Joint Global Ocean Flux Study (JGOFS) presents a unique opportunity and challenge to the data management community because of the diversity and large size of biogeochemical data sets collected. NABE was a pilot study for JGOFS and has also served as a pilot study within the US NODC for management and archiving of the data sets. The author presents an overview to some of the scientific results of NABE, which will be published as an Introduction to a special volume of NABE results in Deep-Sea Research. An overview of NABE data management is given elsewhere in the present report. This is the first collection of papers from JGOFS. Formed as an international program in 1987, JGOFS has four principal elements: modelling and data management, multidisciplinary regional process studies, a global survey of biogeochemical properties and long-term time series observatories. In 1989-90 JGOFS conducted a pilot process study of the spring phytoplankton bloom, the North Atlantic Bloom Experiment (NABE). JGOFS decided to conduct a large scale, internationally-coordinated pilot study in the North Atlantic because of its proximity to the founding nations of the project, the size and predictability of the bloom and its fundamental impact on ocean biogeochemistry.
AN: 3506564

                                                                    697 of 1521  
TI: Emerging role of atmospheric nitrogen deposition in coastal eutrophication: Biogeochemical and trophic perspectives
AU: Paerl,-H.W.
AF: Inst. Mar. Sci., Univ. North Carolina, Morehead City, NC 28557, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1993 vol. 50, no. 10, pp. 2254-2269
LA: English
ER: M (Marine)
AB: Aapproximately half of the world's oceanic primary production originates in coastal waters which are often nitrogen (N) limited and sensitive to externally supplied N. Among anthropogenically generated N sources, atmospheric deposition of N (ADN) (as wet- and dryfall) contributes 10-50% of the total external N load at present (20-100 mmol N/m super(2)/yr), and this will increase. At current levels, atmospheric N inputs lead to a two- to threefold enhancement of CO sub(2) fixation and chlorophyll a production. ADN may play a central role in mediating "new" production in coastal oceans downwind of emissions. Alterations in productivity, nutrient flux, and trophic changes have recently been documented from the Baltic and North seas, the Northwest Atlantic seaboard, and the Western Mediterranean.
AN: 3506514

                                                                    698 of 1521  
TI: Todorokite formation in seawater by microbial mediation
AU: Takematsu,-N.; Kusakabe,-H.; Sato,-Y.; Okabe,-S.
AF: Inst. Phys. and Chem. Res., Wako-shi, Saitama 351-01, Japan
SO: J.-OCEANOGR.-SOC.-JAPAN-NIHON-KAIYO-GAKKAI 1988 vol. 44, no. 5, pp. 235-243
LA: English
ER: M (Marine)
AB: Microbial manganese oxidation in seawater was carried out in enrichment cultures which were obtained from the seawater supply system at the Marine Science Museum, Tokai University (Shimizu-shi, Japan). The manganese oxide formed was well-crystallized todorokite. The major element composition was within the range of marine manganese concretions and the O/Mn molar ratio was 1.8. The conditions for formation of manganese oxide minerals in marine environments are discussed on the basis of these results.
AN: 3506323

                                                                    699 of 1521  
TI: Arsenic in the sea
AU: Francesconi,-K.A.; Edmonds,-J.S.
AF: Western Australian Mar. Res. Lab., P.O. Box 20, North Beach, Western Australia 6020, Australia
SO: OCEANOGRAPHY-AND-MARINE-BIOLOGY:-AN-ANNUAL-REVIEW. Ansell,-A.D.;Gibson,-R.N.;Barnes,-M.-eds. LONDON-UK UCL-PRESS 1993 vol. 31 vol. 31, pp. 111-151
ST: OCEANOGR.-MAR.-BIOL.-ANNU.-REV. vol. 31
LA: English
ER: M (Marine)
AB: An historical account of marine arsenic research and current views on the biotransformation of arsenic in marine ecosystem is presented. Research on arsenic in marine sediments, sea water, marine algae, and marine animals is reviewed from 1900 to the present. Emphasis is placed on work examining the chemical form of arsenic in the various marine compartments. In marine ecosystems arsenic can occur in many different chemical forms, including arsenite and arsenate, methylarsonic and dimethylarsinic acids, trimethylarsine oxide, tetramethylarsonium ion, arsenobetaine, and a number of arsenic-containing ribosides. The biotransformation of these marine arsenicals is discussed, in particular the biogenesis of arsenic-containing ribosides in marine algae and the origin of arsenobetaine in marine animals are considered.
AN: 3506280

                                                                    700 of 1521  
TI: Use of perfused cores for evaluating extracellular enzyme activity in stream-bed sediments
AU: Marxsen,-J.; Fiebig,-D.M.
AF: Limnol. Flussstn., Max-Planck-Inst. Limnol., P.O. Box 260, D-36105 Schlitz, FRG
SO: FEMS-MICROBIOL.-ECOL. 1993 vol. 13, no. 1, pp. 1-12
LA: English
ER: F (Freshwater)
AB: beta -glucosidase activity was investigated in stream-bed sediments using 4-methylumbelliferyl- beta -D-glucopyranoside (MUF- beta -Glc) as a model substrate. In a perfused core technique, water containing MUF- beta -Glc was perfused up through sediment cores.  beta -glucosidase activity was quantified from the release of fluorescent MUF in water discharged from the cores. At low rates of perfusion, maximum  beta -glucosidase activity (V sub(max)) in perfused sediments was similar to that in suspended (unperfused) sediments. Substrate affinity (K sub(m)) was higher in the suspended sediments. V sub(max) and K sub(m) both increased when the perfusion rate was raised, although naturally-low substrate concentrations could mean that variability in perfusion rates has little effect on enzyme activity in the field. V sub(max) was uninfluenced by whether ground or stream water was perfused through the sediments, but K sub(m) was higher in cores perfused with groundwater. Increasing concentrations of glucose in the perfusion water resulted in a progressive inhibition of  beta -glucosidase activity. Although natural concentrations of glucose were low, the high turnover of enzymatically-released glucose probably means that  beta -glucosidase activity could be regulated by product concentration.
AN: 3505404

                                                                    701 of 1521  
TI: Seasonal variation in net benthic C-mineralization in a shallow estuary
AU: Therkildsen,-M.S.; Lomstein,-B.A.
AF: Dep. Microbial Ecol., Inst. Biol. Sci., Univ. Aarhus, DK-8000 Aarhus-C, Denmark
SO: FEMS-MICROBIOL.-ECOL. 1993 vol. 12, no. 2, pp. 131-142
LA: English
ER: B (Brackish)
AB: Seasonal changes in net benthic C-mineralization were measured as sediment O sub(2) uptake, as well as  sigma CO sub(2) flux from the sediment to the water column. Oxygen uptake varied between 26 and 181 mmol m super(-2) d super(-1) through the year, and  sigma CO sub(2) efflux varied between 17 and 132 mmol m super(-2) d super(-1). Both parameters were related to temperature, and the Q sub(10) for O sub(2) uptake and  sigma CO sub(2) efflux were 2.5 and 2.0, respectively. The  sigma CO sub(2)/O sub(2) ratio varied between 0.8 and 1.0 during most of the year. The  sigma CO sub(2)/O sub(2) ratio was, however, less than 0.8 in late summer and autumn, which might be due to reoxidation of accumulated reduced sulfur compounds and carbonate precipitation. Calcium carbonate deposition by molluscs seemed quantitatively important for the  sigma CO sub(2) efflux in September 1990 and August 1991. The  sigma CO sub(2)/O sub(2) ratio reached a maximum of 1.3 in mid-April during decomposition of benthic and sedimented microalgae. On an annual basis, all the oxidants which were reduced during anaerobic mineralization (e.g., Mn super(2+), Fe super(2+), HS super(-)), apparently were reoxidized by O sub(2), as illustrated by an annual  sigma CO sub(2)/O sub(2) ratio of 0.8.
AN: 3505401

                                                                    702 of 1521  
TI: Biogeochemical cycle of mercury species in the marine environment
AU: Branica,-M.; Mikac,-N.; Kwokal,-Z.
AF: Cent. Mar. Res., "Rudjer Boskovic" Inst., Zagreb, Croatia
SO: FINAL-REPORTS-ON-RESEARCH-PROJECTS-DEALING-WITH-THE-EFFECTS-OF-POLLUTANTS-ON-MARINE-COMMUNITIES-AND-ORGANISMS.#RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-TRAITANT-DES-EFFETS-DE-POLLUANTS-SUR-LES-COMMUNAUTES-ET-LES-ORGANISMES-MARINS. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 73 no. 73, pp. 153-173
ST: MAP-TECH.-REP.-SER. no. 73
LA: English
ER: M (Marine)
AB: Mercury distribution in 2 areas of the Eastern Adriatic was investigated. One area is unpolluted with respect to mercury (Krka river estuary and the Kornati Archipelago) and the other is seriously polluted by mercury from the chlor-alkali plant (Kastela bay). The percentages of organic mercury were: 0.5% in sediment; 4-12% in plankton; 15-66% in mussels and 47-90% in fish. Some fish species contained a very high organic mercury level confirming a successful biomagnification of mercury in this low-mercury environment. A study of the mercury speciation in estuarine water of this stratified estuary showed that in the upper low-salinity water layer the reactive mercury content varied considerably and generally corresponded to the dissolved mercury fraction. Mercury accumulation at the depth of halocline was observed. In the Kastela bay extremely high total mercury concentrations in sediment (200 mg kg super(-1) w.w), water (320  mu g dm super(-3)) and mussels (182 mg kg super(-1) w.w) sampled in front of the chlor-alkali plant decreased rapidly with increasing the distance from the pollution source. It is concluded that levels of mercury in the Mediterranean do not essentially differ from the values obtained throughout the world. The elevated mercury levels in some areas do not apply for the entire Mediterranean waters.
AN: 3505357

                                                                    703 of 1521  
TI: The coral reef ecosystem at Chiriatapu in South Andaman. 2. Chemical ecology and system model
AU: Mukherjee,-B.; Mehrotra,-N.P.
AF: Postgrad. Dep. Zool., Univ. Ranchi, Ranchi 834 001, India
SO: J.-MAR.-BIOL.-ASSOC.-INDIA 1992 vol. 34, no. 1-2, pp. 179-188
LA: English
ER: M (Marine)
AB: The fringing reef at Chiriatapu in South Andaman is a leeward channel reef and presents a topography which ensures substantial water residence time of about 30 days. Water from the open ocean enters the reef with moderate budgets of various chemical constituents across the reef biogeochemical gradients develop in tune with the metabolic rhythm (Photosynthesis, respiration and calcification) of the biota. Organic carbon production, respiration and calcium deposition (gross and net production as inferred from carbon dioxide utilization are 4.25 and 0.56 gC/m super(2)/d respectively, while the rate of calcium carbonate deposition is 1.3 g/m super(3)/d by the biota alter the oxygen and carbon dioxide content, as well as the salinity, together with various ionic species to produce alternate zones of varying chemical speciation. The various factors controlling the circulation pattern has been considered, and a modified mathematical model has been proposed for the ecosystem.
AN: 3504942

                                                                    704 of 1521  
TI: The global methane cycle
AU: Wahlen,-M.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093, USA
SO: ANNU.-REV.-EARTH-PLANET.-SCI. 1993 vol. 21, pp. 407-426
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Methane is a radiatively and chemically important constituent of the Earth's atmosphere, and it substantially contributes to the terrestrial greenhouse effect. Atmospheric mixing ratios of methane are increasing rapidly today, and large natural fluctuations, by a factor of two, have occurred in different climatic periods in the past. Over the recent 200 years, atmospheric methane mixing ratios have increased more than a factor of two over preindustrial values due to anthropogenic influence. While the gross features of the global methane budget are known, the details about individual source strengths are still poorly understood.
AN: 3504727

                                                                    705 of 1521  
TI: Chitin production by crustaceans in marine ecosystems
OT: La production de chitine par les crustaces dans les ecosystemes marins
AU: Jeuniaux,-C.; Voss-Foucart,-M.-F.; Bussers,-J.C.
AF: Lab. Morphol. Systematique Ecol., Inst. Van Beneden, quai Van Beneden, 22 B-4020 Liege, Belgium
CO: 1. European Crustacean Conf., Paris (France), 31 Aug-4 Sep 1992
SO: AQUAT.-LIVING-RESOUR.-RESSOUR.-VIVANTES-AQUAT. 1993 vol. 6, no. 4, pp. 331-341
LA: English
ER: M (Marine)
AB: Chitin is synthesized by numerous animal species, either unicellular organisms or metazoans, belonging mainly to zoological groups of the Coelomate Spiralia lineage. However, the produced chitin in marine ecosystems is principally by crustaceans. A comparative study of analytical data so far available allowed calculation of chitin biomass and chitin production values in some types of marine ecosystems, and thus estimation of the quantitative importance of chitin in the biogeochemical cycles of carbon and nitrogen. The main data so far available concerns mediterranean plankton in Calvi bay (Corsica), arctic and antarctic krill, lobster population on South African coasts, and infralittoral benthic communities growing on rocky substrates on Corsica coasts. In all these case, chitin production was estimated roughly at 1g per year and per square meter of rocky substrate or sea surface. Taking into account these production values and the relative extent of the main marine ecosystems over the world, the total production of chitin due to marine crustaceans was estimated at about 2.3 billion metric tons per year.
AN: 3501287

                                                                    706 of 1521  
TI: Oxygen and carbon dioxide water-sediment interface in the southwest lagoon of New Caledonia: Methods and raw data
OT: Flux d'oxygene et de gaz carbonique a l'interface eau-sediment dans le lagon sud-ouest de Nouvelle-Caledonie: Methodes et recueil des donnees
AU: Garrigue,-C.; Clavier,-J.; Boucher,-G.; Gerard,-P.; Menou,-J.L.
AF: Inst. Fr. Rech. Sci. Dev. Coop., ORSTOM, B.P. A5, Noumea, New Caledonia
SO: RAPP.-SCI.-TECH.-SCI.-MER-BIOL.-MAR.-CENT.-NOUMEA-ORSTOM NOUMEA-NEW-CALEDONIA ORSTOM 1992 no. 62, 21 pp
LA: French
ER: M (Marine)
AB: Incubation chambers were used to study aerobic and anaerobic metabolism of the benthos at the water-sediment interface. Triplicate incubations were carried out in darkness during 5 hours on fourteen stations allocated on the three bottom types previously described in the lagoon. Oxygen probes were used for continuous oxygen recording. Water pH measured with glass electrodes, salinity and temperature were used in order to calculte dioxide carbon flux. Water samples were withdrawn with syringes at the beginning and at the end of each incubation for total alkalinity measurements using potentiometric titration. Calcium carbonate flux were evaluated. 15 incubations were carried out to measure chemical oxygen flux of sediment. At the end of the incubations, samples were collected in the enclosed substrate for analysis on sediment parameters (granulometry, organic matter) and living organisms (ATP, photosynthetic pigments, macrobenthos). This paper presents methods used and raw data obtained during two cruises of R.V. ALIS in the south-west lagoon of new Caledonia, from 10 to 20 December 1991 and from 6 to 9 January 1992.
AN: 3501142

                                                                    707 of 1521  
TI: In situ assessment of denitrification in running waters: Example of the Charente River
OT: Etude experimentale de la denitrification in situ en eaux courantes: Application a la Riviere Charente
AU: Torre,-M.; Rebillard,-J.P.; Ayphassorho,-H.; Labroue,-L.; Helmer,-C.
AF: Cent. Natl. Mach. Agric., Genie Rural Eaux Foret, Div. Qual. Eaux, B.P. 3, 33611 Gazinet Cedex, France
SO: ANN.-LIMNOL. 1992 vol. 28, no. 3, pp. 263-271
LA: French
ER: F (Freshwater)
AB: The aim of this study was to quantify the denitrification rate and to insert it in a nitrate hydrological model. The comparison of the field measurements and evaluation by calculation of the denitrification phenomenon shows that it is preferable to estimate the denitrification rate by direct titration instead of nitrogen form analysis.
AN: 3501102

                                                                    708 of 1521  
TI: Organic production and excretion by different phytoplankton size classes
AU: Legrand,-C.; Malinsky-Rushansky,-N.Z.
AF: Cent. Rech. Ecol. Mar. Aquacult. de l'Houmeau (CNRS-IFREMER), BP 5 F-17137, L'Houmeau, France
CO: Int. Symp. on Measurement of Primary Production from the Molecular to the Global Scale, La Rochelle (France), 21-24 Apr 1992
SO: MEASUREMENT-OF-PRIMARY-PRODUCTION-FROM-THE-MOLECULAR-TO-THE-GLOBAL-SCALE.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-LA-ROCHELLE,-21-24-APRIL-1992. COPENHAGEN-DENMARK ICES 1993 vol. 197 p. 280
ST: ICES-MAR.-SCI.-SYMP. vol. 197
NT: Summary only.
LA: English
ER: M (Marine); F (Freshwater)
AB: Excretion rates of photosynthetic products by different classes of phytoplankton are difficult to compare, partly because of the different assay techniques or laboratory instruments used. The purpose of this research is to compare the carbon fluxes between nano- and pico-planktonic eukaryotic algae from salt ponds and lake water respectively, using identical techniques and laboratory equipment. Photosynthetic particulate organic carbon assimilation (POC) and excretion of dissolved organic compounds (DOC) by the algae as well as the subsequent bacterial assimilation and respiration were measured by  super(14)C technique using differential filtration. The percentage of extracellular release (PER) of dissolved organic compounds was lower (3.3-5.0%) for larger algal cells than for the picoeukaryotes (10.9%). PER of a natural mixed salt pond phytoplankton population was intermediate (9.7%), while maximal values for the picoplanktonic natural freshwater fraction was 8%. Bacterial assimilation of the DOC released by the algae under these growth conditions seems to be related more to algal species than to biovolume, although there may also be an effect of the different and specific bacterial assemblages. The remineralization of the total DOC respired to CO sub(2) was higher for the freshwater (18.3%) than for the salt pond (7.3-16.3%) populations. Great variations were found in the respiration rates of natural bacteria from DOC excreted by the freshwater picoalgae (94%) and from these excreted by the nanoplanktonic salt pond algae (0-59%). Results show that bacterial assimilation and mineralization of DOC contributes actively (irrespective of phytoplankton biovolume) to the carbon flux in freshwater and in marine environments. Higher bacterial respiration rate and higher picoplankton excretion rates were observed in fresh water, suggesting a relatively higher flux of carbon by this pathway in fresh water than in salt water. Results also show that assimilation of CO sub(2) by algae, measured by the  super(14)C technique, can be incorrectly evaluated if the amounts of extracellular release as well as the percentage of bacterial assimilation and mineralization are ignored.
AN: 3053679

                                                                    709 of 1521  
TI: The Bolin-65 Symposium
AU: Rodhe,-H.-(ed.)
CO: Bolin-65 Symp., Stockholm (Sweden), 20-23 May 1990
SO: TELLUS-A-B 1991 vol. 43A-B, no. 4, 203 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The papers in this special joint issue of Tellus A and B were presented at a Symposium in honour of Professor Bert Bolin on the occasion of his 65th birthday and retirement from Stockholm University. 50 of Bert Bolin's colleagues and collaborators over the years met at Oersundsbro outside Stockholm to discuss past, present and possible future developments in our understanding of the atmospheric system. The theme of the Symposium was "Atmospheric Sciences--Quo Vadimus?". This theme is a broad one including such questions as Where are we?, Where did we come from?, Where are we going? and What are the issues for the future? The presentations and discussions were organized in the following five sessions: General Circulation of the Atmosphere, Numerical Weather Prediction, Ocean Modelling, Biogeochemical Cycles, and Global Change. These topics not only cover a wide range of issues in atmospheric science, but they also show the development in Bert Bolin's scientific research interests. The very wide definition of atmospheric science, including parts of oceanography and biology/ecology, is a characteristic feature of Bert's scientific thinking: to integrate physical, chemical and biological processes in the environment into a holistic picture of the whole climate system, including the cycling of energy, water and other substances.
AN: 3052628

                                                                    710 of 1521  
TI: Terrestrial biogeochemical cycles: Global interactions with the atmosphere and hydrology
AU: Schimel,-D.S.; Kittel,-T.G.F.; Parton,-W.J.
AF: Resour. Ecol. Lab., Colorado State Univ., Fort Collins, CO 80523, USA
CO: Bolin-65 Symp., Stockholm (Sweden), 20-23 May 1990
SO: THE-BOLIN-65-SYMPOSIUM. Rodhe,-H.-ed. 1991 vol. 43A-B, no. 4 pp. 188-203
ST: TELLUS-A-B vol. 43A-B, no. 4
LA: English
ER: F (Freshwater)
AB: Ecosystem scientists have developed a body of theory to predict the behavior of biogeochemical cycles when exchanges with other ecosystems are small or prescribed. Recent environmental changes make it clear that linkages between ecosystems via atmospheric and hydrological transport have large effects on ecosystem dynamics when considered over time periods of a decade to a century, time scales relevant to contemporary humankind. Our ability to predict behavior of ecosystems coupled by transport is limited by our ability (1) to extrapolate biotic function to large spatial scales and (2) to measure and model transport. We review developments in ecosystem theory, remote sensing, and geographic information systems (GIS) that support new efforts in spatial modeling. A paradigm has emerged to predict behavior of ecosystems based on understanding responses to multiple resources (e.g., water, nutrients, light).
AN: 3052595

                                                                    711 of 1521  
TI: On the control of the carbon-oxygen system
AU: Walin,-G.
AF: Dep. Oceanogr., Univ. Gothenburg, Box 4038, S-40040 Gothenburg, Sweden
CO: Bolin-65 Symp., Stockholm (Sweden), 20-23 May 1990
SO: THE-BOLIN-65-SYMPOSIUM. Rodhe,-H.-ed. 1991 vol. 43A-B, no. 4 pp. 121-135
ST: TELLUS-A-B vol. 43A-B, no. 4
LA: English
ER: M (Marine)
AB: The dynamical aspects of the carbon-oxygen system in the ocean and atmosphere are considered. The analysis is based on the stoichiometry of the main-reactions, relevant continuity constraints and assumptions about feedback from the state of the system. It is found that silicate weathering, though necessary for the forcing of the system, may be unimportant for the control of the system. It is thus fully possible that the stability is taken care of by feedback on the burials of carbonate, reduced carbon and sulphide, which flows may have the potential to be very sensitive to modest perturbations of the state of the ocean-atmosphere system. It is show that the coupling between the carbon and oxygen cycles becomes stronger, if silicate weathering is less important for the control, which has interesting consequences. In general, the need to keep the carbon cycle balanced on the long time scale characterizing the oxygen cycle has important implications. If feed back from pCO sub(2) on silicate weathering is sufficiently weak, we thus find that a positive feedback from pO sub(2) on the rate of burial of reduced carbon may be favourable for the stability of the system, contrary to what is commonly assumed. It is discussed how the frequency of forest fire may have a key position in the control system together with the degree of oxygen depletion in oceanic deep water, since these phenomena may provide "switches" for the formation of charcoal (i.e., deposition of reduced carbon) and burial of sulfide.
AN: 3052585

                                                                    712 of 1521  
TI: Molecular biology in studies of oceanic primary production
AU: LaRoche,-J.; Geider,-R.J.; Falkowski,-P.G.
AF: Oceanogr. and Atmos. Sci. Div., Dep. Appl. Sci., Brookhaven Natl. Lab., Upton, NY 11973, USA
CO: Int. Symp. on Measurement of Primary Production from the Molecular to the Global Scale, La Rochelle (France), 21-24 Apr 1992
SO: MEASUREMENT-OF-PRIMARY-PRODUCTION-FROM-THE-MOLECULAR-TO-THE-GLOBAL-SCALE.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-LA-ROCHELLE,-21-24-APRIL-1992. COPENHAGEN-DENMARK ICES 1993 vol. 197 pp. 42-51
ST: ICES-MAR.-SCI.-SYMP. vol. 197
LA: English
ER: M (Marine)
AB: Remote sensing and the use of moored in situ instrumentation has greatly facilitated measurements of phytoplankton chlorophyll on global scales with high temporal resolution. However, the interpretation of these measurements with respect to primary production and biogeochemical cycles requires an understanding of physiological and biochemical processes in phytoplankton. For example, the use of satellite images of surface chlorophyll to estimate primary production is often based on the functional relationship between photosynthesis and irradiance. A variety of environmental factors such as light, temperature, and nutrient availability affect the photosynthesis/irradiance (P vs I) relationship in phytoplankton. Molecular biology provides a means to study the underlying mechanisms by which the primary producers respond to variable environmental factors. The authors present three examples showing how molecular biology can potentially be used to provide basic insight into the factors controlling primary productivity. The three examples are: (1) Light intensity regulation in which an environmental cue leads to changes in gene expression. (2) Multiple probing of photosynthetic protein expressions to test and explain biophysical and photophysiological responses. (3) Expression of specific proteins induced by nutrient limitation as a potential means of identifying factors limiting photosynthesis in the sea. These examples reflect the personal research interests of the authors, and were selected as illustrations of the potential applications of molecular biology to the study of gene regulation in natural phytoplankton.
AN: 3051112

                                                                    713 of 1521  
TI: Remote sensing of water-column primary production
AU: Sathyendranath,-S.; Platt,-T.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
CO: Int. Symp. on Measurement of Primary Production from the Molecular to the Global Scale, La Rochelle (France), 21-24 Apr 1992
SO: MEASUREMENT-OF-PRIMARY-PRODUCTION-FROM-THE-MOLECULAR-TO-THE-GLOBAL-SCALE.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-LA-ROCHELLE,-21-24-APRIL-1992. COPENHAGEN-DENMARK ICES 1993 vol. 197 pp. 236-243
ST: ICES-MAR.-SCI.-SYMP. vol. 197
LA: English
ER: M (Marine)
AB: Satellite observations of ocean colour at selected wavelengths have made it possible to map near-surface distribution of phytoplankton pigments at the global scale. While the advantage of remote sensing in providing synoptic coverage of large-scale surface features is incontestable, the estimation of primary production from these data requires additional information inaccessible to present-day satellite remote sensing, such as the parameters for conversion of biomass to growth rates, and the parameters describing the vertical structure of biomass. The value of remote sensing would therefore be enhanced considerably if the satellite data could be combined with in situ data to provide the missing information. Since satellite and in situ data are collected at very different time and space scales, conceptual schemes are necessary to render the two data sets compatible. The idea of bio-geochemical provinces has proved to be very useful in this context. Both empirical and analytic approaches have been used to address the problem of estimating primary production from satellite-derived biomass estimates. The various analytic models that have been proposed can be classified according to their level of complexity. In any application, a suitable model has to be selected, based on: (1) validity of the model assumptions in the particular context, (2) computational requirements, (3) availability of auxiliary data, and (4) acceptable levels of error.
AN: 3039099

                                                                    714 of 1521  
TI: Ecology and evolution of microbial populations for bioremediation
AU: Liu,-S.; Suflita,-J.M.
AF: Dep. Bot. Microbiol., Univ. Oklahoma, Norman, OK 73019, USA
SO: TRENDS-BIOTECHNOL. 1993 vol. 11, no. 8, pp. 344-352
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Bioremediation exploits the genetic diversity and metabolic versatility of microorganisms for the transformation of contaminants into less-harmful end-products, which are then integrated into natural biogeochemical cycles. Understanding the ecology, physiology and evolution of degradative microorganisms is critical for the successful consideration and implementation of bioremediation. This article focuses on the common ecological and evolutionary constraints that influence bioremediation processes.
AN: 3035994

                                                                    715 of 1521  
TI: A high-temperature catalytic oxidation method for the determination of marine dissolved organic carbon and its comparison with the UV photo-oxidation method
AU: Chen,-W.; Wangersky,-P.J.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
SO: MAR.-CHEM. 1993 vol. 42, no. 2, pp. 95-106
LA: English
ER: M (Marine)
AB: A modified high-temperature catalytic oxidation (HTCO) method for marine dissolved organic carbon (DOC) measurement is described. The method has a high oxidation efficiency and a precision of 1-2%. It is robust and relatively easy to perform, and hence can be used for routine analyses. Components of the system blank are determined by the use of deionized water treated by high-temperature catalysed oxidation, and the results are checked by an experiment using  super(14)C. Extensive comparisons between this method and UV photo-oxidation are presented. The HTCO method consistently yields 5-60% more DOC than the UV method, with most results in the range of 10-40%. No simple explanation has been found for the differences between the two methods, as a result of the complex nature of DOC in seawater.
AN: 3035239

                                                                    716 of 1521  
TI: Mercury biogeochemical cycling in a stratified estuary
AU: Mason,-R.P.; Fitzgerald,-W.F.; Hurley,-J.; Hanson,-A.K.,Jr.; Donaghay,-P.L.; Sieburth,-J.M.
AF: Ralph M. Parsons Lab., Build. 48-108, MIT, Cambridge, MA 02139, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1227-1241
LA: English
ER: B (Brackish)
AB: Total Hg in the permanently stratified Pettaquamscutt estuary was < 25 pM throughout the water column, even in highly sulfidic bottom waters. Particulate Hg was typically > 40% of the total Hg. Reactive Hg (Hg sub(R)) was generally < 3 pM and decreased with depth, but there is Hg sub(R) even in the anoxic bottom waters. Elemental Hg (Hg super(0)) was highest in the mixed layer and below the detection limit at depth. Demethylation is not an important source of Hg super(0) in this estuary. Dimethylmercury was not detected. Monomethylmercury (MMHg) was near the detection limit in the mixed layer and increased rapidly in the low oxygen region. Dissolved MMHg correlated with bacteriochlorophyll pigments, suggesting that the microbial community plays an important role in MMHg production in this estuary. The overall distributions of dissolved and particulate Hg species result from the interaction with Fe and Mn redox cycling, particulate scavenging and sinking, and MMHg production in the pycnocline. The estimated rate of MMHg production from Hg sub(R) in the pycnocline region is 1.7%/d. Hg super(0) and MMHg are formed principally in the mixed layer and in the pycnocline region, respectively. Particulate scavenging is important, and sedimentation, methylation, and Hg super(0) production are the principal sinks for Hg sub(R).
AN: 3035029

                                                                    717 of 1521  
TI: Iron and regenerated production: Evidence for biological iron recycling in two marine environments
AU: Hutchins,-D.A.; DiTullio,-G.R.; Bruland,-K.W.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1242-1255
LA: English
ER: M (Marine)
AB: The authors investigated biological Fe recycling in plankton communities from two contrasting marine ecosystems, the equatorial Pacific and Monterey Bay, California. Our experiments involved addition of cultured cyanobacteria and diatoms labeled with Fe radiotracer to natural plankton communities. Transfer of label into the natural community was followed by size fractionation and microautoradiography, and intracellular Fe was determined with titanium wash techniques. We documented the transfer of labeled Fe from added cyanobacteria to indigenous large cells in both environments and from large diatoms to indigenous small cells in the equatorial Pacific. Microautoradiography and Ti washing verified that transfer occurred from and into intracellular fractions in Monterey Bay experiments, although substantial amounts of transferred Fe were also found to be surface-adsorbed or associated with detritus. We argue that, as is the case for N, recycling of cellular Fe to support regenerated production could be an important component of marine ecosystem dynamics, especially in areas low in Fe.
AN: 3035020

                                                                    718 of 1521  
TI: Bacterial growth efficiency on natural dissolved organic matter
AU: Kroer,-N.
AF: Natl. Environ. Res. Inst., Dep. Mar. Ecol. and Microbiol., Frederiksborgvej 399, DK-4000 Roskilde, Denmark
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1282-1290
LA: English
ER: M (Marine)
AB: Bacterial growth efficiency was examined in batch cultures and continuous flow cultures by inoculating natural assemblages of pelagic bacteria from different localities into particle-free water. Growth efficiencies were determined from direct measurements of particulate organic carbon (POC) produced and dissolved organic carbon (DOC) used. On average, 6% of the DOC was consumed during growth in batch cultures. Depending on sampling locality, the DOC consumed was converted to bacterial biomass with efficiencies ranging from 26 to 61%. The efficiency did not correlate with either concentration of DOC or temperature. In continuous flow cultures, growth efficiency increased progressively with increasing ammonium concentration but decreased with increasing substrate C:N ratio. The results suggest that the C:N ratio of the bacterial substrate can be a major determinant of bacterial growth efficiency and that differences in growth efficiency between sampling stations can be attributed to differences in the concentration of usable N in the substrate.
AN: 3034965

                                                                    719 of 1521  
TI: Reply to the comment by Jackson  (zooplankton and particle flux below the euphotic zone)
AU: Najjar,-R.G.; Toggweiler,-J.R.
AF: Natl. Cent. Atmos. Res., P.O. Box 3000, Boulder, CO 80307, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1331-1332
LA: English
ER: M (Marine)
AB: In his comment concerning zooplankton and their relationship to the particle flux below the euphotic zone, Jackson (1993) suggests that the assumption of a constant remineralization length scale is important with regard to the conclusions of these modeling studies. In particular, he suggests that a shorter remineralization length scale in regions of higher productivity (where animal populations are greater) would improve simulation of the nutrient distribution. We disagree.
AN: 3034866

                                                                    720 of 1521  
TI: Carbon cycling: Regional and Global Factors Affecting Climate Change
AU: Harger,-J.R.E.; Sorensen,-K.W.; Khalil,-M.A.K.-(eds.)
CO: Conf. on Carbon Cycling: Regional and Global Factors Affecting Climate Change, Kuala Lumpur (Malaysia), 24-26 Oct 1991
SO: CHEMOSPHERE 1993 vol. 27, no. 6, 222 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Because of the current trends in atmospheric carbon dioxide and trace gases and the prospect of global warming, the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the Department of Environment of Malaysia, and the United Nations Environment Program (UNEP) organized this Workshop. The aim of the workshop was to evaluate available data on past, present, and future atmospheric chemical composition (with emphasis on carbon dioxide), the response of marine and terrestrial ecosystems on the enrichment of atmospheric carbon, and to recommend actions to counteract anticipated global climatic warming. In the discussions on present carbon storage and its relation to the Earth's climate, the participants identified the sources of energy and exploitation of forest resources as the two most significant issues related to global climate change. The discussions concluded that anthropogenic contribution of carbon to the atmosphere, through fossil fuel burning, deforestation, and other processes, would be the main mechanism driving climate change. In the future, the necessary increases in the energy needs to support the growth of population and per capita demands of the region and the rest of the world, will dominate the carbon flux to the atmosphere. The study of the past records in relation to climate change is important to test the validity of the hypotheses and assumptions used for climate modeling in predicting future climate change. Moreover, the participants concluded that although we know little about the actual sinks, we know enough to realize that it is prudent to take steps to stabilize the climate since the capacity of natural environment for sequestering carbon has been exceeded by current anthropogenic releases.
AN: 3034542

                                                                    721 of 1521  
TI: (Phenotypic and genetic evolution of enterobacterial pathogens in the marine environment (sediments, biomass).)
OT: Evolution phenotypique et genetique des enterobacteries pathogenes dans le milieu marin (sediments, biomasse)
AU: Gauthier,-M.J.
AF: INSERM, Unit. 303 "Mer et Sante", France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 43-63
ST: MAP-TECH.-REP.-SER. no. 49
LA: French
ER: M (Marine)
AN: 3033397

                                                                    722 of 1521  
TI: (Adaptation of enterobacterial pathogens to sea water (Escherichia coli model).)
OT: Adaptation des enterobacteries pathogenes a l'eau de mer (modele Escherichia coli)
AU: Gauthier,-M.J.; Munro,-P.M.; Breittmayer,-V.A.
AF: INSERM, Unit. 303 "Mer et Sante", France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 33-42
ST: MAP-TECH.-REP.-SER. no. 49
LA: French
ER: M (Marine)
AN: 3033396

                                                                    723 of 1521  
TI: Some environmental factors affecting survival of faecal pathogens and indicator organisms in seawater
AU: El-Sharkawi,-F.; El-Attar,-L.; Abdel-Gawad,-A.; Molazem,-S.
AF: Dep. Environ. Health and Microbiol., High Inst. Public Health, Univ. Alexandria, Egypt
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 21-32
ST: MAP-TECH.-REP.-SER. no. 49
LA: English
ER: M (Marine)
AB: This study is conducted to determine the effect of some environmental factors such as temperature, salinity and light on the rate of die-off Salmonella typhi, S. wein, Shigella flexneri and Escherichia coli as examples of faecal pathogens and indicators in water. These organisms are tested in different kinds of water: seawater, filter sterilized seawater, tap water and normal saline. The organisms were counted every 2 hours for 8 hours and then every day up to 7 days. It is found that there is no great difference in survival time of the organisms tested at temperatures of 25 to 35 degree  C, but at 40 degree  C they died off more rapidly. The salinity of seawater does not affect the survival time of Salmonella, Sh. flexneri. E. coli appears to survive longer in fresh water than in seawater at temperatures between 30 and 35 degree C. Daylight, i.e. sunlight, has a lethal effect on all test organisms. Survival time being shorter when exposed to daylight than in the dark in different types of waters, being up to a maximum of 24 hours as compared to several days in the dark. Artificial light has less effect than natural daylight.
AN: 3033395

                                                                    724 of 1521  
TI: Survival of some intestinal pathogens in the marine environment
AU: Fuks,-D.
AF: Rudjer Boskovic Inst., Cent. Mar. Res. Rovinj, G. Paliaga 5, 52210 Rovinj, Yugoslavia
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 1-20
ST: MAP-TECH.-REP.-SER. no. 49
LA: English
ER: M (Marine)
AB: The purpose of this study is to determine the effects of organic matter, temperature and light intensity on the survival of some Salmonella and Shigella strains, Escherichia coli and faecal coliforms in a marine environment, and in laboratory-performed experiments with natural seawater. The survival of all Salmonella and Shigella strains tested and of faecal coliforms, is higher in all experiments compared to E. coli. The results confirm that sea temperature may exert an important influence on the magnitude of decay rates of salmonellas, shigellas and E. coli. In situ experiments reveal that a large amount of organic matter may overcome the bactericidal effects of sea temperature and light on the bacteria tested. Although the die-off rate of E. coli does not differ significantly from S. typhimurium in some experiments, their different tolerance to light and temperature has to be taken into account particularly when E. coli is utilized as an indicator of S. typhimurium presence in seawater. The discrepancy between die-off rates of S. typhimurium and faecal coliforms increases from 27 m depth to the surface. Even if S. typhimurium and faecal coliforms have similar die-off rates, various combinations of detrimental factors could exert different influence on the tested pathogenic bacteria and indicator bacteria. Therefore, although faecal coliforms should be used as indicators of pathogenic bacteria present in the sea, they should not constitute the only such indicator.
AN: 3033394

                                                                    725 of 1521  
TI: Biogeochemical cycles of specific pollutants (Activity K). Survival of pathogens.
OT: Cycles Biogeochimiques de polluants specifiques (Activite K). Survie des pathogenes
CA: UNEP Mediterranean Action Plan, Athens (Greece)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1991 no. 49, 72 pp
LA: English
ER: M (Marine)
AB: Contributions are abstracted and indexed individually.
AN: 3033393

                                                                    726 of 1521  
TI: Marine bacterial expression of the RecA gene in response to UV light
AU: Coffin,-R.B.; Jeffrey,-W.H.; Ferrante,-A.A.; Miller,-R.V.
AF: U.S. EPA, Gulf Breeze Environ. Lab., Gulf Breeze, FL 32561, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993 vp
NT: Summary only.
LA: English
ER: M (Marine)
AB: In response to the recent concern for stratospheric ozone depletion the authors examined the effect of natural ultraviolet (UV) radiation on the activity of marine bacteria. Reduction of ozone concentration selectively limits stratospheric adsorption of UV-B (290-320 nm) radiation, resulting in higher radiance on the earth's surface. Oligotrophic marine environments have been a focus of this research because high water clarity allows significant penetration of ultraviolet light to depths of 20 to 30 meters. Increased intensity of UV radiation may have significant effect on the abundance, diversity and evolution of marine bacteria through damage to DNA. A seemingly ubiquitous response in bacteria to DNA damage from UV is the induction of the S.O.S. network by the recA gene product. To study the bacterial response to UV, the authors examined both transcription and translation of the recA gene. Translation was examined using antisera raised against the Escherichia coli RecA protein. Preliminary data suggest that bacteria that are exposed to sunlight in the surface ocean contain higher concentrations of the RecA protein than cells collected from the deep ocean (> 500M). Furthermore, a diel variation in the RecA protein concentration of surface bacteria was observed. Using oligonucleotide gene probes, based on highly concerned regions of the RecA protein. mRNA (transcription) has been measured. The authors are refining this probe and plan to report on comparisons of mRNA and protein concentrations.
AN: 3028444

                                                                    727 of 1521  
TI: Defining the chemical character of aerosols from the atmosphere of the Mediterranean Sea and surrounding regions
AU: Chester,-R.; Nimmo,-M.; Alarcon,-M.; Saydam,-C.; Murphy,-K.J.T.; Sanders,-G.S.; Corcoran,-P.
AF: Oceanogr. Lab., Dep. Earth Sci., Univ. Liverpool, L69 3BX, UK
SO: OCEANOL.-ACTA 1993 vol. 16, no. 3, pp. 231-246
LA: English
ER: M (Marine)
AB: Atmospherically-transported trace metals can play an important role in biogeochemical cycles in the Mediterranean Sea. However, although the magnitude of trace metal air to sea fluxes is initially dependent on the metal concentrations in the air, it is the "chemical character" of the aerosol which constrains the fate of the metals in sea water. To a first approximation the chemical composition of the Mediterranean particulate aerosol is controlled by the extent to which an anthropogenic-rich "background" material, having a mainly European origin, is perturbed by mixing with crustal components having a desert origin. These perturbations offer an environmentally meaningful index which can be used to define the "chemical character" of the Mediterranean particulate aerosol in terms of the manner in which trace metals are partitioned between the anthropogenic and crustal components. This "chemical character" concept was assessed using: a) a total of 83 particulate aerosols collected on a W  arrow right  E transect across the Mediterranean Sea and surrounding regions; and b) particulate aerosol populations from a number of adjacent coastal seas.
AN: 3027215

                                                                    728 of 1521  
TI: A multilevel model for the study of the dynamics of the North Adriatic Sea
AU: Betello,-G.; Bergamasco,-A.
AF: IBM Eur. Cent. Sci. Eng. Comput., Roma, Italy
CO: Ecological Problems of the Adriatic Sea Symp., Split (Croatia), 7-9 Nov 1990
SO: ECOLOGICAL-PROBLEMS-IN-THE-ADRIATIC-SEA.-A-SYMPOSIUM-HELD-IN-SPLIT,-CROATIA,-7-9-NOVEMBER,-1990. 1991 vol. 32, no. 2 pp. 587-598
ST: ACTA-ADRIAT. vol. 32, no. 2
RN: 3
LA: English
ER: M (Marine)
AB: A method which can be applied to describe, understand and forecast phenomena characterizing a semi-enclosed basin will be discussed. A numerical multilevel model that can be used as a basic structure in biological, geological and chemical research will be presented. In particular its application has been made in the North Adriatic Sea because this area offers the opportunity to study a variety of interesting phenomena. Different numerical experiments were carried out, using 7 km regular grid, 10 vertical levels with different thickness, different boundary conditions, different wind fields; the Po runoff and subsequent advection diffusion of a passive scalar was taken into account. The results of the IBM-3090/VF implementation of the model will be shown.
AN: 3024964

                                                                    729 of 1521  
TI: Primary ocean production: Carbon and particle flux.
OT: Production primaire oceanique: Flux de carbone et de particules
AU: Morel,-A.
CA: Paris-6 Univ. (France)
SO: 1990 8 pp
NT: NTIS Order No.: N91-23596/0/GAR.
LA: French
ER: M (Marine)
AB: The role of the ocean and its vegetation with regard to the carbon and other cycles is discussed. Comprehension of the flux between the atmosphere and the ocean in stationary conditions at the interface and at the interior of the ocean is considered. Present incertitudes with regard to the marine biomass carbon content, the flux entering, the net carbon flux at the base of the superficial layer, and the flux in a column of water down to the sediment are presented. Possible progressions are given. (In Esa, Space and Sea p 233-240.)
AN: 3023004

                                                                    730 of 1521  
TI: Coupling of cycles and global significance of sediment diagenesis
AU: Blackburn,-T.H.; Blackburn,-N.D.
AF: Dep. Microbial Ecol., Inst. Biol. Sci., Aarhus Univ., DK 8000 Aarhus C, Denmark
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MARINE-SEDIMENTS,-BURIAL,-PORE-WATER-CHEMISTRY,-MICROBIOLOGY-AND-DIAGENESIS. 1993 vol. 113, no. 1-2 pp. 101-110
ST: MAR.-GEOL. vol. 113, no. 1-2
LA: English
ER: M (Marine)
AB: A system dynamics simulation model was used to illustrate the interconnections between carbon, nitrogen, sulfur and oxygen cycling in a marine sediment, where sulfide diffusion occurred (Diff+) and where it was absent (Diff-), due to the formation of insoluble compounds. The model contained 12 sediment layers (0.5 mm at the top) and one water layer of 20 m, which was a source for oxygen and sulfate, and a sink for molecules diffusing from the sediments. Particulate organic matter was evenly distributed throughout the sediment down to 3.5 cm. It was allowed to produce dissolved organic carbon (DOC) at low, medium and high rates of 18.6, 37.2 and 55.8 mmol m super(-2)/d, respectively. Because of the distribution of organic matter, the flux of DOC from the sediment was low, 2-3%. Sulfate was the main oxidant of DOC, 81-89% for Diff- and 94-96% for Diff+; O sub(2) and NO sub(3) super(-) were of minor importance as oxidants. Most nitrogen left the sediment as NH sub(4) super(+) (72-95%) with Diff+, but NH sub(4) super(+) efflux was less important in Diff- simulations (16-58%). The difference was due to high rates of nitrification in the latter situation; NO sub(3) super(-) efflux accounted for 38-22% and N sub(2) efflux for 44-18% of the total nitrogen efflux. The high nitrification rates with Diff- were consistent with a large proportion of O sub(2) being used to oxidise NH sub(4) super(+) (72-66% total O sub(2)). Most O sub(2) (91-99%) was used to oxidise HS super(-), where HS super(-) was allowed to diffuse. These data agree with the following explanation: if organic matter is oxidised by SO sub(2) super(2-) reduction, deep in the sediment, and if there is no HS super(-) diffusion, then only NH sub(4) super(+) diffuses to the sediment surface and is oxidised. This is because there is little organic carbon, and no HS super(-), at the sediment surface to compete with NH sub(4) super(+) for O sub(2). The NO sub(3) super(-) which is produced, can then be denitrified efficiently at low organic loading, but at high loading, the sediment becomes more anoxic and the zone of nitrification moves closer to the sediment surface, creating the possibility for a greater NO sub(3) super(-) efflux. The implications of these predictions for global processes are discussed.
AN: 3021949

                                                                    731 of 1521  
TI: Geochemistry of Recent oxic and anoxic marine sediments: Implications for the geological record
AU: Calvert,-S.E.; Pedersen,-T.F.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MARINE-SEDIMENTS,-BURIAL,-PORE-WATER-CHEMISTRY,-MICROBIOLOGY-AND-DIAGENESIS. 1993 vol. 113, no. 1-2 pp. 67-88
ST: MAR.-GEOL. vol. 113, no. 1-2
LA: English
ER: M (Marine)
AB: The distributions of certain minor and trace elements in marine sediments should potentially provide forensic tools for determining the redox conditions of the bottom waters at the time of deposition. The ability to identify such conditions in the geological past is important because current models of the conditions of formation of organic-rich rocks require reexamination, a method to determine whether the areal extent of anoxic waters expanded or retracted in response to palaeoceanographic changes is required, and the effects of such environmental changes on the geochemical balance of these elements in the ocean need to be understood. Recent research has suggested that some minor and trace elements are precipitated where free dissolved sulphide is present (Cu, Cd, Ni, Zn) without undergoing a valency change, whereas others undergo a change in valency and are either more efficiently adsorbed onto solid surfaces under oxic (I) or anoxic (V) conditions or are precipitated under anoxic conditions (Cr, Mn, Mo, Re, U, V). Hence, the enrichment of these minor and trace elements relative to their crustal abundances indicates that the host sediments accumulated under anoxic conditions, although not necessarily under anoxic bottom waters. Examination of the chemical composition of the sediments of anoxic basins, continental margin sediments and oxidized deepsea sediments shows that I and Mn enrichments are reliable indicators of bottom water oxygenation, whereas enrichments of the remaining elements reflect either bottom water anoxia or element uptake by subsurface anoxic sediments below a relatively thin surficial oxic veneer. Hence, the absence of metal enrichment in these cases can be taken as firm evidence that the bottom waters of a basin of sedimentation were not anoxic. These behaviours may be used to propose, for example, that the Holocene sapropel in the Black Sea accumulated under oxic bottom waters, whereas the modern facies reflects its formation under the prevailing intensely anoxic conditions, and that the Panama Basin bottom waters were not anoxic during the Last Glacial Maximum when the rate of accumulation of organic carbon increased. Likewise, the enrichment of Mn as a mixed carbonate phase in some ancient black shales strongly suggests that they formed under oxic bottom waters rather than anoxic conditions as is commonly assumed.
AN: 3021926

                                                                    732 of 1521  
TI: Enzymatic iron and uranium reduction by sulfate-reducing bacteria
AU: Lovley,-D.R.; Roden,-E.E.; Phillips,-E.J.P.; Woodward,-J.C.
AF: 430 Natl. Cent., Water Resour. Div., U.S. Geol. Surv., Reston, VA 22092, USA
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MARINE-SEDIMENTS,-BURIAL,-PORE-WATER-CHEMISTRY,-MICROBIOLOGY-AND-DIAGENESIS. 1993 vol. 113, no. 1-2 pp. 41-53
ST: MAR.-GEOL. vol. 113, no. 1-2
LA: English
ER: M (Marine)
AB: The potential for sulfate-reducing bacteria (SRB) to enzymatically reduce Fe(III) and U(VI) was investigated. Five species of Desulfovibrio as well as Desulfobacterium autotrophicum and Desulfobulbus propionicus reduced Fe(III) chelated with nitrilotriacetic acid as well as insoluble Fe(III) oxide, Fe(III) oxide reduction resulted in the accumulation of magnetite and siderite. Desulfobacter postgatei reduced the chelated Fe(III) but not Fe(III) oxide. Desulfobacter curvatus, Desulfomonile tiedjei, and Desulfotomaculum acetoxidans did not reduce Fe(III). Only Desulfovibrio species reduced U(VI). U(VI) reduction resulted in the precipitation of uraninite. None of the SRB that reduced Fe(III) or U(VI) appeared to conserved enough energy to support growth from this reaction. However, Desulfovibrio desulfuricans metabolized H sub(2) down to lower concentrations with Fe(III) or U(VI) as the electron acceptor than with sulfate, suggesting that these metals may be preferred electron acceptors at the low H sub(2) concentrations present in most marine sediments. Molybdate did not inhibit Fe(III) reduction by D. desulfuricans. This indicates that the inability of molybdate to inhibit Fe(III) reduction in marine sediments does not rule out the possibility that SRB are important catalysts for Fe(III) reduction. The results demonstrate that although SRB were previously considered to reduce Fe(III) and U(VI) indirectly through the production of sulfide, they may also directly reduce Fe(III) and U(VI) through enzymatic mechanisms. These findings, as well as our recent discovery that the S degree -reducing microorganism Desulfuromonas acetoxidans can reduce Fe(III), demonstrate that there are close links between the microbial sulfur, iron, and uranium cycles in anaerobic marine sediments.
AN: 3021904

                                                                    733 of 1521  
TI: Marine sediments, burial, pore water chemistry, microbiology and diagenesis
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MAR.-GEOL. 1993 vol. 113, no. 1-2, 145 pp
LA: English
ER: M (Marine)
AB: This volume includes papers on sediment chemistry, specific indicators of biogeochemical processes in the geological past and how they responded to environmental change, and the role of microbes in biogeochemical cycles.
AN: 3021749

                                                                    734 of 1521  
TI: Microbial formation and transformation of organometallic and organometalloid compounds
AU: Gadd,-G.M.
AF: Dep. Biol. Sci., Univ. Dundee, Dundee DD1 4HN, UK
SO: FEMS-MICROBIOL.-REV. 1993 vol. 11, no. 4, pp. 297-316
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Microbial formation and transformation of organometallic and organometalloid compounds comprise significant components of biogeochemical cycles for the metals mercury, lead and tin and the metalloids arsenic, selenium, tellurium and germanium. Methylated derivatives of such elements can arise as a result of chemical and biological mechanisms and this frequently results in altered volatility, solubility, toxicity and mobility. The major microbial methylating agents are methylcobalamin (CH sub(3)CoB sub(12)), involved in the methylation of mercury, tin and lead, and S-adenosylmethionine (SAM), involved in the methylation of arsenic and selenium. Evidence for the methylation of other toxic metal(loid)s is sparse. Biomethylation may result in metal(loid) detoxification since methylated derivatives may be excreted readily from cells, are often volatile and may be less toxic, e.g. organoarsenicals. However, for mercury, low yields of methylated derivatives and the existence of more efficient resistance mechanisms, e.g. reduction of Hg super(2+) to Hg super(0), suggest a lower significance in detoxification. Bioalkylation has only been characterised in detail for arsenic. Microorganisms can accumulate organometal(loid)s, a phenomenon relevant to toxicant transfer to higher organisms. As well as bioaccumulation, many microorganisms are capable of the degradation and detoxification of organometal(loid) compounds by, e.g. demethylation and dealkylation. Several organometal(loid) transformations have potential for environmental bioremediation.
AN: 3020847

                                                                    735 of 1521  
TI: The Parana floodplain lakes (Argentina): Overview of major hydrological, biogeochemical, and ecological features
AU: Carignan,-R.; Neiff,-J.J.
AF: INRS, Univ. Quebec, C.P. 7500, Ste-Foy, PQ G1V 4C7, Canada
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993 vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Compared to other major South American rivers, relatively low flood amplitude and unpredictable hydrology confer distinct biogeochemical and ecological attributes to the floodplain lakes of the Parana River. Direct influx of dissolved nutrients from the river is uncommon and nutrient cycles are usually dominated by internal sources. Floating macrophyte production is limited by N during summer, whereas phytoplankton production can be limited by N or by light in the more turbid systems. Remote sensing (SPOT) and field observations suggest that morphometry and turbidity determine to a large extent whether the lakes will be dominated by floating macrophytes (Eichhornia), submerged macrophytes (Cabomba), or phytoplankton. Because successive flood events vary in amplitude, duration and timing, their effects on the lakes are highly variable from year to year.
AN: 3020259

                                                                    736 of 1521  
TI: The silica cycle in the Antarctic Ocean: Is the Weddell Sea atypical?
AU: Leynaert,-A.; Nelson,-D.M.; Queguiner,-B.; Treguer,-P.
AF: Inst. d'Etudes Mar., URA CNRS 1513, BP 452, F-29275 Brest Cedex, France
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 96, no. 1, pp. 1-15
NT: Bibliogr.:61 ref.
LA: English
ER: M (Marine)
AB: The lowest biogenic silica production rates in the Southern Ocean (average of 2.59 mmol Si m super(-2)/d) have been recorded in an area of heavy ice cover along a transect through the Weddell Sea from Joinville Island to Cap Norvegia (November-December 1990). The associated biomass was also very low (concentrations  less than or equal to 0.6  mu mol/l for biogenic silica and  less than or equal to 0.8  mu g/l for chlorophyll a). Based upon these direct measurements of biogenic silica production rates and other data available from the marginal ice zone and open ocean areas, we estimated the annual production of biogenic silica in the northern Weddell Sea to be 810 to 870 mmol m super(-2)/yr. This leads to a revised estimate of the total annual biogenic silica production in the Southern Ocean of between 11 and 32 Tmol Si/yr. Comparing our annual production estimate to previous estimates of vertical flux of opal in the Weddell Sea, we conclude that no more than 1% of the silica produced annually by phytoplankton in the upper water column reaches a depth of 800 m. This is consistent with the general distribution of high accumulation rates of opal in Southern Ocean sediments which evidence an unexplained gap in the Weddell Sea. Thus, regarding the cycling of biogenic silica in the Southern Ocean, the Weddell Sea appears to be atypical.
AN: 3020085

                                                                    737 of 1521  
TI: A coupled physical-biochemical lake model for forecasting water quality. Application to the Northern Basin of Lake Lugano
AU: Karagounis,-I.; Troesch,-J.; Zamboni,-F.
AF: Lab. Hydraul., Hydrol. and Glaciol., ETH-Zentrum, CH-8092 Zurich, Switzerland
SO: AQUAT.-SCI. 1993 vol. 55, no. 2, pp. 87-102
LA: English
ER: F (Freshwater)
AB: A new one-dimensional numerical model that includes physical and biochemical processes has been developed. The biochemical processes, influenced by the lake dynamics, are required for forecasting water quality. The model is used to investigate the effects of different internal restoration measures, such as artificial mixing, input of oxygen and drainage of deep water. The model is applied to the Northern Basin of Lake Lugano, a Swiss-Italian border lake. The lake is highly eutrophic and chemically stratified throughout the year. The model was calibrated over one year and validated over a period of several years. The results agree well with the measured data. The coupled model reproduces the observed depth dependency of conductivity even during long simulation times. Due to the predominant mixing, decoupled physical models cannot maintain such gradients. The forecasting capabilities of the model are demonstrated for different case studies. The impact of restoration measures on water quality is rather small. Best results are achieved by reducing the external nutrient loading. Caution is recommended for internal measures as these have to be studied in greater detail.
AN: 3018928

                                                                    738 of 1521  
TI: Enhanced particle flux through the biodeposition by the Antarctic suspension-feeding bivalve Laternula elliptica in Marian Cove, King George Island
AU: Ahn,-In-Young
AF: Polar Ecol. Lab., Polar Res. Cent., Korea Ocean Res. and Dev. Inst., Ansan, P.O. Box 29, Seoul 425-600, South Korea
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1993 vol. 171, no. 1, pp. 75-90
LA: English
ER: M (Marine)
AB: The infaunal lamellibranch Laternula elliptica (Laternulidae), one of the most Antarctic bivalves, is widely distributed in shallow waters around the Antarctic Continent. In order to evaluate the contribution of this species to organic carbon flux in an Antarctic coastal ecosystem, biodeposition rates by L. elliptica were measured and compared with sedimentation without this bivalve species in laboratory experiments during one austral summer. The amount of deposited material increased in the presence of L. elliptica. Weight-specific biodeposition rates varied from 0.26 to 2.17 mg dry wt/g wet wt/d and the rate decreased with increase in body weight. Due to massive inflows of terrigenous sediment through coastal meltwater stream into the coastal water, fecal and pseudofecal material contained a considerable amount of mineral particles and only a small percentage of organic carbon (1.6-5.2%). Estimated particulate organic carbon flux through the biodeposition of L. elliptica is [95 mg C/m super(2)/d, an amount comparable to that of a typical suspension-feeding bivalve, Mytilus edulis, L. elliptica is apparently an important agent for sedimentation of both lithogenic particles and organic particles. Thus, this study suggests that L. elliptica play an important role in enhancing particle flux from water column to sea bed through biodeposition and possibly nourishing other benthic fauna, particularly in phytoplankton-impoverished nearshore waters.
AN: 3018639

                                                                    739 of 1521  
TI: Nuclear and isotopic techniques for investigating marine pollution
AU: Mee,-L.D.; Readman,-J.W.
AF: IAEA-MEL's Mar. Environ. Stud. Lab.
SO: IAEA-BULL. 1993 vol. 35, no. 2, pp. 2-8
LA: English
ER: M (Marine)
AB: A survey of selected applications that scientists are using to identify, trace, and investigate contamination of the oceans.
AN: 3014576

                                                                    740 of 1521  
TI: Community structure and functional roles of meiofauna in the North Sea
AU: Heip,-C.; Huys,-R.; Alkemade,-R.
AF: Cent. Estuar. Coastal Ecol., Netherlands Inst. Ecol., Vierstr. 28, 4401 EA Yerseke, Netherlands
CO: The Other North Sea, Amsterdam (Netherlands), 21 Feb 1992
SO: THE-OTHER-NORTH-SEA:-PROCEEDINGS-OF-A-SYMPOSIUM. 1992 vol. 26, no. 1 pp. 31-41
ST: NETH.-J.-AQUAT.-ECOL. vol. 26, no. 1
LA: English
ER: M (Marine)
AB: Knowledge on community structure of North Sea meiofauna has greatly increased recently. A quasi-synoptic picture of meiofauna densities and copepod community structure from 171 stations of the southern North Sea, sampled in April-May 1986, has been obtained during the North Sea Benthos Survey. Latitudinal patterns in meiofauna abundance and copepod weight, abundance and diversity exist in an area between 51 degree 30'N and 58 degree 30'N. Using TWINSPAN-classification five major groups of copepod species can be recognized which are related to sediment type, latitude and depth. The part of the meiofauna in total benthic energy flow, their role in the benthic food web and in biogeochemical cycles is discussed based on existing literature. There are still considerable gaps in knowledge and the field is not progressing rapidly.
AN: 3013582

                                                                    741 of 1521  
TI: Dynamics of dimethylsulfide in coastal waters and the marine atmosphere: A need for platform observations
AU: Dacey,-J.W.H.; Cooper,-D.J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA, USA
SO: MAR.-TECHNOL.-SOC.-J. 1993 vol. 27, no. 2, pp. 72-77
NT: Offshore Platform Technology for Science.
LA: English
ER: M (Marine)
AB: Time series measurements of dimethylsulfide in seawater and in the atmosphere will yield valuable insight into the variability of and the controls on this rapidly cycling and important biogeochemical compound. It is vitally important to have access to a stable platform that will allow measurements during periods of high wind speed when gas exchange is rapid and when shipboard measurements are impossible. Assessment of ancillary parameters in the water will increase our understanding of the biological and physical factors influencing DMS cycling in seawater. Simultaneous measurements in the surface water in the atmospheric boundary layer will allow evaluation of sea-air flux models and will aid in unravelling the proposed climate feedbacks associated with DMS.
AN: 3013247

                                                                    742 of 1521  
TI: Technology and related developments for interdisciplinary global studies
AU: Dickey,-T.D.
AF: Univ. Southern California, Univ. Park, Los Angeles, CA 90089, USA
SO: SEA-TECHNOL. 1993 vol. 34, no. 8, pp. 47-54
LA: English
ER: M (Marine)
AB: The term global change usually connotes climate change--a bias toward physical aspects. However, it involves considerably more diverse and complex set of scientific problems related to the biology and chemistry of our planet. For this reason, interdisciplinary research directed toward global scale problems has become the focus for many oceanographers recently. Major programs such as the Joint Global Ocean Flux Study (JGOFS) and the Global Ocean Ecosystem Dynamics (GLOBEC) programs are well underway. The U.S. components are primarily administered and funded by NSF with additional funds from agencies such as NOAA, NASA, ONR, DOE, and EPA. Both programs have international components and coordinating organizations critical to their success.
AN: 3013049

                                                                    743 of 1521  
TI: Lake-groundwater interaction: Critical needs, new approaches
AU: Bowser,-C.J.
AF: Dep. Geol. and Geophys., Univ. Wisconsin, Madison WI, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993 vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Lakes are not isolated from their terrestrial surroundings, and a better understanding of interactions of lakes with surrounding terrestrial regions is critically needed. Because of their higher solute concentrations groundwaters exert considerable chemical "leverage" on lakes. Groundwater flow modeling has been relatively expensive from the standpoint of personnel training, drilling costs, and computer modeling requirements. Recently other methods have been used to estimate lake hydrologic budgets that are potentially much less costly. Use of stable isotopic tracers of oxygen and deuterium enable evaluation of lake hydrologic budgets, and, through inverse techniques, enable determination average input groundwater composition. Results from a LTER site in northern Wisconsin provide new insights into silica cycling in lakes, potassium loading from leaf litterfall, and road salt contamination. Mass balance approaches combined with more careful analysis of mineralogical and geological characteristics of surrounding terrain can help better define the controls on the composition of these waters. Other isotopic systems (e.g.  super(87)Sr/ super(86)Sr, delta  super(13)C) can further improve these models.
AN: 3011951

                                                                    744 of 1521  
TI: Meromixis in hypersaline Mono Lake, California. 3. Biogeochemical response to stratification and overturn
AU: Miller,-L.G.; Jellison,-R.; Oremland,-R.S.; Culbertson,-C.W.
AF: U.S. Geol. Survey, Water Resour. Div., Menlo Park, CA 94025, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 5, pp. 1040-1051
LA: English
ER: B (Brackish)
AB: Mono Lake is a terminal, saline lake that became ectogenically meromictic in 1982-1983 and remained stratified until November 1988. During this period, the monimolimnion remained anoxic and nearly isothermal, while the upper mixolimnion was well oxygenated and exhibited a seasonal thermal regime. Dissolved sulfide and methane increased in the monimolimnion as a result of diffusive flux from the sediments. Winter mixing down to the chemocline distributed sulfide and methane throughout the mixolimnion. Lakewide inventories of dissolved sulfide and methane reflected the balance between increased concentrations and decreased monimolimnion volume over time. At overturn, the entire water column was isothermal and anoxic. Dissolved sulfide (380 x 10 super(6) mol) was oxidized in 1 week by molecular oxygen. Methane (12 x 10 super(6) mol) was removed more slowly by microbial oxidation and ventilation across the air-water interface.
AN: 3005617

                                                                    745 of 1521  
TI: A coccolithophorid bloom in Jervis Bay, Australia.
AU: Blackburn,-S.I.; Cresswell,-G.
AF: Div. Fish., CSIRO, GPO Box 1538, Hobart, Tas. 7001, Australia
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1993. vol. 44, no. 2, pp. 253-260
LA: English
ER: M (Marine)
AB: A massive algal bloom of the coccolithophorid Gephyrocapsa oceanica  Kamptner (Prymnesiophyceae) developed in Jervis Bay, a coastal embayment at 34 degree S on the New South Wales coast, in mid December 1992. The bloom coloured the entire bay a dramatic milky blue-green, which was clearly visible from aircraft and detectable in the visible band by the US satellite NOAA-11. The bloom, which reached cell densities of 1.8 x 10 super(7) cells/L, persisted for a month. Such high densities of coccolithophorids have not been recorded before in Australian waters. Furthermore, it is the first record, world-wide, of a large-scale mono-specific bloom of G. oceanica). The bloom is suggested to have been driven by an intrusion of continental-slope water that continuously entered into the bottom of the bay.
AN: 3004423

                                                                    746 of 1521  
TI: Fate of a phytoplankton spring bloom: Sedimentation and carbon flow in the planktonic food web in the northern Baltic.
AU: Lignell,-R.; Heiskanen,-A.-S.; Kuosa,-H.; Gundersen,-K.; Kuuppo-Leinikki,-P.; Pajuniemi,-R.; Uitto,-A.
AF: Dep. Limnol., Univ. Helsinki, SF-00710 Helsinki, Finland
SO: MAR.-ECOL.-PROG.-SER. 1993. vol. 94, no. 3, pp. 239-252
NT: Bibliogr.: 77 ref.
LA: English
ER: B (Brackish)
AB: During the spring bloom in 1988, the dynamics of planktonic carbon flow were studied weekly in the euphotic layer in the northern Baltic. The spring bloom developed after the formation of a slight vertical salinity gradient near the surface at the end of April, and a peak in phytoplankton primary productivity and biomass (dominated by the dinoflagellate Peridiniella catenata ) was reached about 1 wk later. The biomass of all heterotrophic compartments, especially that of bacteria and copepods, increased strongly during the peak and declining phases of the algal bloom, showing that their success was closely linked with the bloom. During the whole bloom period, the integral primary production ( super(14)C incorporation) was 45.5 g C/m super(2), and "new" (NO sub(3)@)u--N-based) production contributed about 80% of this value. The rotifers-copepods grazing chain and the bacteria-heterotrophic nanoflagellates-ciliates "microbial loop" consumed directly about the same amount (3.5 g C/m super(2)) of phytoplankton carbon. Algae accounted for 64% of the total carbon consumption of zooplankton.
AN: 3001866

                                                                    747 of 1521  
TI: Decomposition of mud-flat annual plant litter on a drawdown marsh surface.
AU: Wrubleski,-D.A.; Murkin,-H.R.; Van-Der-Valk,-A.G.; Davis,-C.B.
AF: Inst. Wetland and Waterfowl Res., Iowa State Univ. Ames, IA 50011, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: This study examined the decomposition of above- and below-ground plant litter of three dominant mud-flat annuals (Aster brachyactis , Atriplex patula  and Chenopodium rubrum ) during an experimental drawdown of a 10-cell complex in the Delta Marsh, Manitoba. Aboveground shoots exhibited a near linear loss of mass over the two years of the experiment, with little difference between species. Belowground roots of Aster  and Atriplex  lost mass at a faster rate than shoots during the first year, whereas the opposite was found for Chenopodium . The roots of all three species exhibited little mass loss during the second year. After two years all plant litters had similar mass remaining except for Chenopodium  roots which had lost the least amount. All litters released phosphorus over the two years, except Chenopodium  roots which nearly doubled in total phosphorus. Nitrogen levels were much more varied between species and parts.
AN: 3001702

                                                                    748 of 1521  
TI: Dissolved inorganic carbon utilization in relation to calcite production in Emiliania huxleyi  (Lohmann) Kamptner.
AU: Dong,-L.F.; Nimer,-N.A.; Okus,-E.; Merrett,-M.J.
AF: Sch. Biol. Sci., University Coll. Swansea, Singleton Park, Swansea SA2 8PP, UK
SO: NEW-PHYTOL. 1993. vol. 123, no. 4, pp. 679-684
LA: English
ER: F (Freshwater)
AB: The relationship between calcite production and dissolved inorganic carbon (DIC) utilization was investigated using high- and low-calcifying strains of Emiliania huxleyi  aerated with either air (0.03% v/v CO sub(2)) or CO sub(2)-free air. With cultures grown on air, calcite production was eight-fold greater in the high-calcifying culture, but growth rates for high- and low-calcifying cultures were similar. Growth and calcite production were accompanied by a concomitant decrease in DIC and free CO sub(2) in the high-calcifying culture, showing that HCO sub(3) super(-) provides inorganic carbon for calcite synthesis. In low-calcifying cultures DIC and free CO sub(2) were relatively constant, confirming that cells acquire inorganic carbon mainly by the diffusive entry of free CO sub(2). When cultures were aerated with CO sub(2)-free air the free CO sub(2) concentration was below the K sub(0.5)(CO sub(2)) for high- and low-calcifying cells and the low-calcifying cells were unable to grow. Growth of high-calcifying cells was observed, and the calcite yield was little changed from cultures gassed with air (0.03% v/v CO sub(2)). At these minimal CO sub(2) concentrations HCO sub(3) super(-) may provide inorganic carbon for calcite synthesis and CO sub(2) for photosynthesis, allowing growth to occur. Calcite synthesis by E. huxleyi) decreases DIC and carbonate alkalinity in cultures not in equilibrium with the gas phase.
AN: 3001480

                                                                    749 of 1521  
TI: The release of trace elements by dying marine phytoplankton.
AU: Fisher,-N.S.; Wente,-M.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP.. 1993. vol. 40, no. 4, pp. 671-694
LA: English
ER: M (Marine)
AB: The extent to which sinking phytoplankton can directly influence the cycling and vertical transport of metals in the oceans depends largely on the loss rates of the metals from dying cells during their descent. This was examined in a series of radiotracer experiments in which a diatom, a dinoflagellate, and a coccolithophore each accumulated Se, Ag, Sn, Au and Am and then were maintained in the dark for up to 10 days to assess depuration kinetics. Concurrent measurements were made of cell counts and particulate C, N and dry weight. Se was taken up actively by the cells, Sn and Am passively, and Ag and Au uptake patterns varied with the species. The coccolithophores had less reactive surfaces for these metals than did the other species, as reflected in lower metal uptake and greater metal release. Generally, those metals with greatest particle affinity during uptake (Am, Sn, Ag) were retained for the longest periods. All cells decomposed over time, so that particulate C and N decreased by up to 10.7 and 9.8%/day, respectively, in diatom cultures, up to 4.7 and 4.9%/day in dinoflagellate cultures, and up to 6.5 and 6.0%/day in coccolithophore cultures. In the diatoms, all elements except Se were released more slowly than C and N from the particulate phase, resulting in increasing metal:C (or N) ratios with time, while Se was released faster than C or N. With the dinoflagellates, elemental release generally followed C and N release, while with the coccolithophores elements were released more rapidly than C and N from the particulate phase. Metals (especially Am, Ag, Sn) were retained sufficiently long, even by decomposing cells, to suggest that phytoplankton sinking as aggregates at rates of 100 m/day would effectively transport these metals hundreds of meters out of oceanic surface waters.
AN: 2996790

                                                                    750 of 1521  
TI: Changes in the functioning of wetlands along environmental gradients.
AU: Brinson,-M.M.
AF: Dep. Biol., East Carolina Univ., Greenville, NC 27858, USA
SO: WETLANDS. 1993. vol. 13, no. 2, spec. iss., pp. 65-74
LA: English
ER: F (Freshwater)
AB: One of the prevalent gradients in wetlands is the continuum of depth and frequency of flooding. While much emphasis has been placed on the importance of hydrology as a driving force for wetlands, few other perspectives have emerged to demonstrate unifying patterns and principles. In contrast to the wetness continuum, the functioning of wetlands can be separated into two broad categories: (1) landscape-based transitions that occur within a wetland or group of similar wetland types and (2) resource-based transitions that allow comparisons of the flow of water and processing of nutrients among very different wetland types. Landscape-based continua include the transition from upstream to downstream in riverine wetlands and between aquatic and terrestrial ecosystems within a wetland. Along the upstream-downstream continuum, sources of flood-water delivery change dominance from ground-water discharge and overland runoff, as in low order streams, to dominance by overbank flooding, as in high order streams. With increasing size, properties related to the aquatic-to-terrestrial transition are replaced by properties related to wetland-atmospheric exchanges and by landscape maintenance, the latter not normally acknowledged as a wetland function. Resource-based continua include the extremes of (1) sources of water to wetlands (precipitation, overland flow, and ground water) and (2) the variation in inflows and outflows of nutrients and sediments. Emphasis on water source forces consideration of controls beyond the wetland's boundaries. A broader view of biogeochemical functioning is gained by categorizing wetlands into groups based on the exchange of nutrients and sediments among landscape units rather than on serving as a sink or source for a particular element. Based on this analysis, the less frequently flooded or saturated portions of wetlands are no less functionally active than wetter portions; the functions are simply different. Efforts to classify wetlands according to their hydroperiod do little to reveal their fundamental properties.
AN: 2995986

                                                                    751 of 1521  
TI: Role of zooplankton in the cycling and remineralization of chemical materials in the Southern California Bight. Progress report 5, June 15-November 14, 1988.
CA: Oregon State Univ., Corvallis (USA). Sch. of Oceanography
SO: REP.-U.S.-DEP.-ENERGY. 1988. 5 pp
NT: NTIS Order No.: DE90006696/GAR.
LA: English
ER: M (Marine)
AB: The overall objective of our research is to understand the transport pathways and mass balances of selected metabolically active and inactive chemical species in the Santa Monica/San Pedro Basins. One focus of our study is to examine the role of zooplankton and micronekton in the cycling and remineralization of chemical materials in the Southern California Bight, with particular reference to C, N and certain radionuclides and trace metals. A second focus is to examine these same radionuclides and trace metals in other important reservoirs. Knowledge of the rates and routes of transfer of these nuclides and metals through these reservoirs should lead to a cogent model for these elements in SM/SP Basins. Our zooplankton C and N data, should lead ultimately to a model of C and N cycling in the upper water column. Our sediment core data will lead to the construction of mass balances and budgets in the SM/SP Basins. (Contract FG05-85ER60340. Sponsored by Department of Energy, Washington, DC. Portions of this document are illegible in microfiche products.)
AN: 2995275

                                                                    752 of 1521  
TI: Atmospheric oxygen variation through geologic time.
AU: Kump,-L.R.; Kasting,-J.F.; Robinson,-J.M.
AF: Earth System Sci. Cent., Pennsylvania State Univ., University Park, PA 16802, USA
CO: Atmospheric Oxygen Variation Through Geologic Time, University Park, PA (USA), 16-18 Jul 1990
SO: GLOBAL-PLANET.-CHANGE. 1991. vol. 5, no. 1-2, 131 pp
NT: Palaeogeogr., Palaeoclimatol., Palaeoecol. vol. 97, no. 1-2.
LA: English
AB: Molecular oxygen is an important component of the Earth system. Its atmospheric abundance substantially influences the chemical behavior of the atmosphere, the metabolism of organisms, photosynthesis, respiration, and decomposition on land and in the ocean, the frequency and intensity of forest fires, and crustal weathering processes. Although on societal time scales the abundance of O sub(2) is unchanging, on geologic time scales the possibility of substantial fluctuations exists. The timing, magnitude, causes, and effects of O sub(2) variation through Earth history are, however, poorly known. In hope of stimulating such investigation, a workshop attended by experts in the fields of atmospheric chemistry, paleontology, geochemistry, physiology, and ecology was held at the Earth System Science Center of the Pennsylvania State University from July 16-18, 1990. The workshop was divided into three sessions. The first session addressed the functional, quantitative, and diagnostic aspects of O sub(2) in modern biogeochemical cycles. The second and final sessions focussed on theoretical, empirical, and inferential indicators of oxygen variations over Phanerozoic (the last 600 Ma), and Precambrian (from 3.8 Ga to 0.6 Ga) time, respectively.
AN: 2990317

                                                                    753 of 1521  
TI: Composition, productivity and nutrient chemistry of a coastal ocean planktonic food web.
AU: Verity,-P.G.; Yoder,-J.A.; Bishop,-S.S.; Nelson,-J.R.; Craven,-D.B.; Blanton,-J.O.; Robertson,-C.Y.; Tronzo,-C.R.
AF: Skidaway Inst. Oceanogr., P.O. Box 13687, Savannah, GA 31416, USA
SO: CONT.-SHELF-RES. 1993. vol. 13, no. 7, pp. 741-776
LA: English
ER: M (Marine)
AB: A 3 year field study was conducted to investigate patterns, magnitude and variability of primary production; the abundance, biomass and composition of producers and consumers; and the relative importance of physical and chemical variables associated with these parameters, in inner shelf waters of the South Atlantic Bight. Discrete interval, time series and continuous measurements were made along a transect and at two process-oriented stations during summer and winter 1985-88. A quasi-permanent density front constrains low salinity (<34 ppt) waters to within ca 10 km of the coast. These waters contain abundant autotrophic and heterotrophic communities. Primary production is high, 6-7 x 10 super(2) gC/m super(-2)/year, and is apparently subsidized by rapid nutrient recycling in the water column, sediments and adjacent salt marshes. Silicate is notable for its excess concentrations year-round and supports substantial diatom productivity. Correlation analyses suggest that Si strongly influences phytoplankton biomass, whereas growth rates are coupled to availability of light and NH sub(4). Despite evidence of considerable variability in primary production over daily to interannual scales, plankton biomass is relatively constant. Experimental studies suggest a tight coupling between primary producers and microconsumers, and support the hypothesis that substantial fractions of primary and secondary production are recycled within the water column.
AN: 2989778

                                                                    754 of 1521  
TI: Artificial nutrient enrichment of two meromictic lakes in southeast Alaska to rehabilitate indigenous sockeye salmon (Oncorhynchus nerka ) populations.
AU: Barto,-D.L.; Haddix,-M.
AF: Alaska Dep. Fish and Game, F.R.E.D. Div., Limnol. Sect., Juneau, AK 99824, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Previous studies of sockeye salmon (Oncorhynchus nerka ) nursery lakes have indicated that the decomposition of adult salmon carcasses can contribute approximately 66% of the total annual nutrient inputs to Alaskan coastal lakes. Gradually declining adult salmon production from Hugh Smith and Redoubt lakes is generally believed to be the direct result of over-fishing. The subsequent decline in returning adult salmon has also reduced the nutrient inputs and the overall lake productivity which directly effects adult fish production. Investigations since 1979 characterized these lakes as having low average nutrient (total P < 5.0 ug/l), Chl  sub(-)a) (<2.0 ug/l) and zooplankton biomass levels and containing monimolimnion layers at depths >80 m. Artificial enrichment delivered liquid ammonium nitrate and ammonium phosphate fertilizer to increase the in-lake total P levels to 5-10 ug/l. Primary and secondary productivity increased during fertilizer application periods while the total P levels did not exceed 90% of the critical loading rates. Zooplankton biomass production doubled at one lake as a direct result of the artificial nutrient additions. Growth and survival indices of juvenile sockeye generally increased and at one lake adult sockeye production increased five fold.
AN: 2989658

                                                                    755 of 1521  
TI: PCBs in Lake Michigan: Linkages to the cycles of biogenic particles and organic carbon.
AU: Armstrong,-D.E.; Shafer,-M.M.; Dean,-K.E.
AF: Univ. Wisconsin, Madison, WI 53706, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
LA: English
ER: F (Freshwater)
AB: Research on the fate and effects of polychlorobiphenyls (PCBs) in Lake Michigan has provided insights into biogeochemical cycles and processes. The fate of PCBs is linked to the cycles of organic carbon and natural particles. Organic carbon, especially lipids, in biogenic particles transports PCBs to bottom sediments. Particle diagenesis in surface sediments removes organic carbon and recycles PCBs into the water column. Organic colloids produced by chemical and biological processes influence removal through particle scavenging, volatilization, and degradation. Ingestion of organic particles incorporates PCBs into the food web. Quantitative information on the pathways of carbon and other biogenic elements in the ecosystem has been obtained from research on PCBs.
AN: 2989477

                                                                    756 of 1521  
TI: The use of carbon isotopes to evaluate sources and sinks of dissolved inorganic carbon in lake watersheds.
AU: Aravena,-R.; Schiff,-S.; Trumbore,-S.; Dillon,-P.
AF: Waterloo Centr. Groundwater Res., Univ. Waterloo, Waterloo, ON N2L 3G1, Canada
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
LA: English
ER: F (Freshwater)
AB: Growing concerns about the global carbon cycle, and the natural and anthropogenic sources and sinks of carbon have fostered renewed research interest in the cycling of carbon in natural systems. This presentation will focus on the use of carbon isotopes ( super(13)C,  super(14)C) to evaluate cycling of dissolved inorganic carbon (DIC) in lake watersheds. Chemical and carbon isotope data collected in acid sensitive lake watersheds in northern Ontario will be presented to illustrate processes that control the carbon isotopic composition of DIC and its use to evaluate DIC fluxes between the main carbon pools that are involved in carbon cycling in lake watersheds.
AN: 2989476

                                                                    757 of 1521  
TI: Evidence for the diffusion of dissolved organic carbon from the sediments of Lake Fryxell, Antarctica.
AU: Aiken,-G.R.; McKnight,-D.M.
AF: U.S. Geol. Surv., Mar. St. Sci. Cent., 3215 Mar. St., Boulder, CO 80303, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Dissolved organic carbon (DOC) in Lake Fryxell, an amictic, permanently ice-covered lake, was studied to determine the influence of biogeochemical processes on its distribution and nature. The DOC depth profile is similar to the profiles for conservative inorganic constituents, such as chloride, indicating that diffusion of organic matter from the bottom waters or sediments of the lake into overlying glacial melt water is the major source of DOC. The  super(14)C ages of the lake fulvic acids suggest that DOC diffusing from the bottom waters is primarily composed of relict organic material with the addition of recent carbon resulting from the degradation of algae and bacteria in the sediments and bottom waters of the lake. The main transformations occurring as aquatic humic substances diffuse upward in the water column are 1) loss of sulfur groups through the oxycline and 2) decrease in aliphatic carbon and increase in the heterogeneity of aliphatic moieties.
AN: 2989467

                                                                    758 of 1521  
TI: The role of manganese reduction in the biogeochemical cycling of manganese in Oneida Lake, New York.
AU: Aguilar,-C.; Nealson,-K.H.
AF: Cent. Great Lakes Stud., Univ. Wisconsin-Milwaukee, Milwaukee, WI 53204, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Manganese is a very reactive redox metal, which exhibits a strong yearly cycle in Oneida Lake, New York. Different methods were used to measure Mn(II) fluxes from the sediments throughout the year. In deep basins of the lake, high rates of Mn(IV) reduction, up to 2.1 mmol/m super(2)/day, were observed during the summer and early fall, with little reduction taking place during the rest of the year. In the shallow areas of the lake, where ferromanganese nodules and crusts are commonly found, there was little or no reduction throughout the year. The manganese cycle is tightly coupled to the carbon cycle, and has a significant role in the oxidation of organic carbon in the lake, derived from the high photosynthetic production and the biomass that collapses and reaches the sediment-water interface.
AN: 2989465

                                                                    759 of 1521  
TI: Systemecological analysis of marine pelagial systems on behalf of microbiological/ planktological variables and pDNA measurements.
OT: Systemoekologische Analyse marine Pelagialsysteme auf der Basis von mikrobiologisch/ planktologischen Variablen und pDNA-Messungen
AU: Karrasch,-B.
AF: Inst. Meereskd., Abt. Mar. Mikrobiol., Duesternbrooker Weg 20, D 24105 Kiel, FRG
CA: Kiel Univ. (FRG). Math.-Nat. Fak.
SO: BER.-INST.-MEERESKD.-CHRISTIAN-ALBRECHTS-UNIV.-KIEL. 1992. vol. 225, 197 pp
NT: Bibliogr.: 327 ref. Diss. (Dr. rer. nat.)
LA: German
ER: M (Marine); B (Brackish)
AB: During spring and summer 1989 investigations were made in 2 areas of the North Atlantic (47 degree N, 20 degree W; 57 degree N, 20 degree W). Further investigations were carried out from late spring to summer in Kiel Bight and Kiel Fjord and in the Western Baltic and during summer 1990 in water enclosures as well as in the Zingster Strom (Dar beta -Zingster bodden area). For this survey, physical planktological and microbiological variables were determined. The aim of this study was the analysis of the structures and dynamic processes in different marine pelagic systems. The relationship of bacterial abundance and biomass to other pelagic components and the energy flow mediated by bacteria were of the main interest. Additionally, the method for the determination of particulate DNA (pDNA) concentrations, developed by Paul & Myers (1982), was optimized in this study. The results of pDNA measurements were correlated with the abundance of bacteria and further pelagic components. Some aspects of this study concerned the seasonal development of pelagic structures, microbial processes within a stratified water body, 'bottom up' control, diurnal biological processes and the influence of hydrographic features (eddies) on auto- and heterotrophic pelagic components.
AN: 2989454

                                                                    760 of 1521  
TI: Dissolved trace metals in the southwestern Indian Ocean.
AU: Morley,-N.H.; Statham,-P.J.; Burton,-J.D.
AF: Dep. Oceanogr., University, Highfield, Southampton SO9 5NH, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP.. 1993. vol. 40, no. 5, pp. 1043-1062
LA: English
ER: M (Marine)
AB: Dissolved trace metal concentrations are reported for a section in the southwestern Indian Ocean, extending from 7 to 27 degree S around the 56 degree E meridian. Overall distributions conform to those found in other oceans, with Cd, Cu, Ni and Zn showing recycled, or nutrient-like, behaviour, whereas Mn is enriched in the mixed layer relative to deep water. Deep-water concentrations of the recycled elements are intermediate between those for the North Atlantic and North Pacific Oceans, as would be expected from known patterns of deep-ocean circulation. For Cd and Zn, depletion in the surface layer approaches detection limits while for Cu and Ni significant near-surface concentrations (0.9 and 2.1 nM, respectively) are found. Relationships between the concentrations of metals and nutrients are similar to those described in the literature for the recycled metals for other regions, although significant variations exist from ocean to ocean. Maximum manganese concentrations in the upper water column are about or below 1 nM, as expected for a region remote from continental sources of airborne particulate material. Minor variations in maximum concentration with latitude are evident as a result of the complex geochemistry of this element. Deep water manganese concentrations are uniformly low, showing no evidence for benthic or hydrothermal sources.
AN: 2989125

                                                                    761 of 1521  
TI: Mathematical model for global ecological investigations.
AU: Krapivin,-V.F.
AF: Inst. Radio Eng. and Electron., Russian Acad. Sci., Fryazino, Vvedenskogo 1, Moscow Reg. 141120, Russia
SO: ECOL.-MODEL. 1993. vol. 67, no. 2-4, pp. 103-127
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The paper gives a schematic description of a mathematical model of the biosphere (MMB) representing interaction of the atmosphere with the land and ocean ecosystems. The model comprises blocks describing biogeochemical cycles of carbon, nitrogen, sulphur, phosphorus and oxygen; global hydrologic balance in liquid, gaseous and solid phases; productivity of soil-plant formations with 30 types defined; photosynthesis in ocean ecosystems taking into account its depth and surface inhomogeneity; demographic processes and anthropogenic changes. The model is designed to be connected to a global climate model. Examples of using the MMB for estimating the state of the biosphere and its subsystems are presented.
AN: 2985529

                                                                    762 of 1521  
TI: Production of nutrients and their contribution to runoff water according to the various uses of the land in the Sierra de Guadarrama (Madrid).
AU: Pareja,-B.L.; Artola,-C.G.; Garcia,-P.G.; Vera,-F.L.
AF: Univ. Coll. San Pablo, C.E.U., Madrid, Spain
SO: J.-ENVIRON.-HYDROL. 1993. vol. 1, no. 2, pp. 35-42
LA: English
ER: F (Freshwater)
AB: The importance that runoff plays in the transport of nutrients was studied in sub-basins that have undergone little alteration and where pressure from man and point pollution do not disguise the influence of the soil. For the purpose of this study sub-basins which are homogeneous in lithology and vegetation were chosen. These sub-basins are located within the watershed of the Santillana Reservoir. Quantitative relations between the variations in runoff and export coefficients which represent the production of nutrients at the level of the basin, were established beforehand. Conclusions derived from the results of the geobiochemical behavior of nitrogen and phosphorus related to our area of study are included.
AN: 2985122

                                                                    763 of 1521  
TI: Carbon and nitrogen budgets of the Arabian Sea.
AU: Somasundar,-K.; Rajendran,-A.; Dileep-Kumar,-M.; Sen-Gupta,-R.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: MAR.-CHEM. 1990. vol. 30, no. 4, pp. 363-377
LA: English
ER: M (Marine)
AB: From the available data, carbon and nitrogen budgets have been estimated for the Arabian Sea (0-25 degree N, 50-80 degree E), taking into consideration the possible sources of fluxes. By our model calculations the annual fluxes into and out of the Arabian Sea were estimated to be 446 and 530 trillion grams (Tg) for carbon, and 8.06 and 3.60 Tg for nitrogen, respectively. The carbon budget was found to be negatively balanced by 84 Tg/year. A possible source to compensate for this deficit could be from the northward movement of Antarctic Bottom Water in the bottom layers, which are probably enriched with anthropogenic carbon dioxide. The percentage loss of carbon (14.0%) to the atmosphere was much lower than that of nitrogen (56.9%). Out of the total amount of denitrified nitrogen (29.5 Tg) only  similar to 7% was lost to the atmosphere. This model suggests that  similar to 6 Tg N/year of denitrified nitrogen of the world's oceans could be liberated to the atmosphere through the surface layer of denitrified areas. A quantitative assessment has been made to account for the excess of nitrogen that could result from N sub(2) fixation by extensive blooms of Trichodesmium) in the Arabian Sea. Based on the standing crop and net outfluxes, estimated residence times were  similar to 944 and 4.04 x 10 super(4) years for carbon and nitrogen, respectively, in the Arabian Sea.
AN: 2985041

                                                                    764 of 1521  
TI: Nutrient chemistry of the water column of Lake Tanganyika.
AU: Edmond,-J.M.; Stallard,-R.F.; Craig,-H.; Craig,-V.; Weiss,-R.F.; Coulter,-G.W.
AF: Dep. Earth, Atmos. Planet. Sci., E34-201, MIT, Cambridge, MA 02139, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 4, pp. 725-738
LA: English
ER: F (Freshwater)
AB: Lake Tanganyika shows permanent thermal stratification with deep-water temperatures that have been stable over the period of observation (since 1939). The lake is anoxic below  similar to 150-m depth. In general the nutrients show Redfield behavior save in the deep waters of the northern basin where large excesses of phosphate and ammonia are present. Bacterial disproportionation of organic material probably plays an important role in producing these excesses. Inorganic desorption from fluvial detritus is also a possible source of excess phosphate in deep waters. The oxic-anoxic boundary at  similar to 150 m is a sink for all forms of fixed nitrogen. Thus the nutrient budget to the lake probably involves fixation of nitrogen in the surface layer in addition to substantial inputs from rainfall and runoff, with the phosphate supplied by vertical mixing. Because these processes are in approximate balance under present conditions, the productivity of the lake must be very sensitive to changes in climatic forcing.
AN: 2983408

                                                                    765 of 1521  
TI: Partitioning of the nitrogen stock in the vicinity of a Fijian seagrass bed dominated by Syringodium isoetifolium  (Ascherson) Dandy.
AU: Yamamuro,-M.; Koike,-I.; Iizumi,-H.
AF: Mar. Geol. Dep., Geol. Surv. Japan, Higashi 1-1-3 Tsukuba, Ibaraki 305, Japan
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1993. vol. 44, no. 1, pp. 101-115
NT: Special issue: Tropical Seagrass Ecosystems.
LA: English
ER: M (Marine)
AB: Partitioning of the nitrogen stock in a Fijian seagrass bed dominated by Syringodium isoetifolium  (Ascherson) Dandy and in an adjacent area bare of macrophytic vegetation was assessed to evaluate the effect of the presence of seagrass on coral sediment. Concentrations of major nutrients, such as nitrogen and phosphate, were as low in the water column at the seagrass bed and the bare area as they were in the open ocean. Concentrations of ammonium and dissolved organic nitrogen, however, were higher in the water within the seagrass canopy than they were in other waters. In sediments at the seagrass bed and the bare area, interstitial nitrogen, such as nitrate and dissolved organic nitrogen, was a minor component of the total nitrogen (0.3-0.05%). On the other hand, concentrations of total organic nitrogen in seagrass-bed sediment (about 70% of which was in the form of amorphous organic nitrogen and the rest of which came from living and dead seagrass) were more than three times higher than those in bare-area sediment. Concentrations of organic carbon from amorphous organic materials in seagrass-bed sediment showed no large change with depth, resulting in an apparent decrease in the carbon/nitrogen atom ratio from 60 to 10. These results suggest some mechanisms to minimize the loss of nitrogen stock from the sediment of tropical seagrass beds.
AN: 2980187

                                                                    766 of 1521  
TI: Carbon inputs and biogeochemical processes at the halocline in a stratified estuary: Krka River, Yugoslavia.
AU: Cauwet,-G.
AF: Lab. Sedimentol. Geochim. Mar., Unite Assoc. CNRS No. 715, Univ. Perpignan, France
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 269-283
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish)
AB: Suspended matter, particulate and dissolved organic carbon and dissolved inorganic carbon were measured seasonally from 1987 to 1989 in the Krka Estuary. Carbon inputs by the river are low, because of the small river flow and the low content of suspended matter of its water. The permanent stratification of the estuary creates an unusual environment, with a very sharp salinity gradient at the freshwater-seawater interface. The accumulation of particulate organic carbon at the interface and the production of dissolved organic carbon suggest that an enhanced biological activity influences the organic matter budget.
AN: 2970954

                                                                    767 of 1521  
TI: Estuarine transformation of organic matter: Single coalescence events of estuarine surface active particles.
AU: Svetlicic,-V.; Zutic,-V.; Tomaic,-J.
AF: Rudjer Boskovic Inst., Cent. Mar. Res. Zagreb, P.O. Box 1016, 41001 Zagreb, Croatia
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 253-267
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish)
AB: Individual surface-active particles (SAP) in aqueous environmental samples can be characterized through their coalescence at a model hydrophobic interface. Each coalescence event is recorded as an electrical signal. As the electrical signal is a current transient (time on a millisecond scale), the sequence of fast processes leading to the formation of a condensed film can be studied from the moment of first attachment at the interface. In the stratified Krka Estuary, SAP are present in maximum concentrations (10 super(7)-5x10 super(8) particles/l in the size range > 1  mu m) at the halocline (freshwater-seawater interface). This highly surface-active fraction of particulate organic matter can be viewed as oily droplets. SAP are fluid, and are readily transformed at interfaces to films of molecular thickness (surface area per particle is in the range 10 super(-5)-10 super(-2) cm super(2)). Comparison of response of individual SAP with model particles, and the frequency of their appearance in estuarine samples, shows that a majority of estuarine SAP has, in terms of viscosity and film permeability, the properties of oleic acid. A significant fraction of SAP have more rigid structures, comparable to oleic acid+cholesterol model particles. A small fraction (< 1%) behaves as phytoplankton cells with fluid outer membranes. We have also presented evidence for a strong interaction between elemental mercury and SAP, which is not sensitive to the molecular structure of the organic phase. The puzzling accumulation of mercury at the halocline of the Krka Estuary may be regarded as the result of interaction of elemental mercury with SAP.
AN: 2970931

                                                                    768 of 1521  
TI: Variations in the chemical lability of iron in estuarine, coastal and shelf waters and its implications for phytoplankton.
AU: Wells,-M.L.; Mayer,-L.M.
AF: Dep. Oceanogr., Univ. Maine, Ira C. Darling Cent., Walpole, ME 04573, USA
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 195-210
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish)
AB: The relationship between total and chemically labile Fe has been studied in estuarine, coastal and shelf waters of the Gulf of Maine, U.S.A. Measurements of the labile fraction of total Fe, defined by complexation with 8-hydroxyquinoline in 1 h, correlate with the availability of Fe to marine phytoplankton and therefore can be used to estimate Fe availability in seawater. The results show that the relative lability (= labile/total) of Fe in seawater varied both spatially and temporally from near-zero to 100%. Although particulate Fe (> 0.45  mu m) was generally less labile than dissolved Fe (< 0.45  mu m), the particulate fraction often contributed substantially to labile Fe concentrations overall. Conversely, as much as 75% of "dissolved" Fe was non-labile, and therefore was probably not available to phytoplankton. In seawater/river-water mixing experiments, aggregation diminished the relative lability of Fe by  similar to 30%, even though much of it remained in the "dissolved" fraction. Considering phytoplankton nutrition, these results demonstrate that equating dissolving Fe concentrations with "available" metal can be misleading. Furthermore, the large variability observed in the labile proportion of total Fe in seawater indicates that Fe availability to phytoplankton cannot be estimated by applying fixed lability-ratios to total Fe concentrations.
AN: 2970783

                                                                    769 of 1521  
TI: Trace metal-nutrient relationships in estuaries.
AU: Windom,-H.; Byrd,-J.; Smith,-R.,Jr.; Hungspreugs,-M.; Dharmvanij,-S.; Thumtrakul,-W.; Yeats,-P.
AF: Skidaway Inst. Oceanogr., P.O. Box 13687, Savannah, GA 31416, USA
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 177-194
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The distributions of cadmium, copper, zinc and nutrients were determined in the estuaries of the Medway (Canada), Savannah (U.S.A.) and Maeklong (Thailand) rivers to assess the influence of biological processes on the trace metal estuarine behavior. These metals were chosen because they show nutrient-type behavior in the ocean. Three types of metal-nutrient relationships were considered: those resulting from biological uptake, regeneration and abiotic processes. Biological uptake was not observed to be an important process affecting trace metal behavior in estuaries. Biological regeneration appears to be an important process only for cadmium, based on its relationship with phosphate or nitrogen. The enrichment of nickel in estuarine waters is greater than can be explained by regeneration of organic material, which suggests that abiotic processes are more important. Zinc is generally removed from solution during estuarine mixing, perhaps associated with iron removal. Copper covaries closely with silica and is suggested to be the result of additional weathering of silicate minerals within the estuarine environment. Results from all the estuarine studies suggest that copper and silica are not fractionated during weathering and transport from the continents to the ocean. Iron-phosphate covariance in the Savannah Estuary is attributed to their simultaneous removal by the formation of FePO sub(4).
AN: 2970746

                                                                    770 of 1521  
TI: Physical, chemical and biological processes in stratified estuaries.
AU: Zutic,-V.-(ed.)
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: MAR.-CHEM. 1991. vol. 32, no. 2-4, pp. 111-385
LA: English
ER: M (Marine); B (Brackish)
AB: Except for their physical scale, small estuaries are as complex as large ones; they contain practically the same unknowns as the large estuaries. However, their small physical scale offers the advantage to perform basic and applied research more efficiently. Furthermore, small estuaries are important per se being demographically and economically attractive, important and ecologically endangered. The Symposium was brought about by the intention to organize a workshop of the French-Yugoslav research group working on the Krka Estuary, a small estuary on the east coast of the Adriatic Sea. The characteristics of this estuary, which in 1985 was declared a national park, are: it is karstic; the terrigenous load and particle content are extremely low; it is highly stratified with sharp and visible fresh water/seawater interface; in its upper and middle reach it is still one of the most pristine estuaries in Europe. Recent multidisciplinary research on the Krka Estuary has resulted in discoveries of a few new phenomena of the fresh water/seawater interface. While physical, chemical and biological processes are better understood at air/water and sediment/water interfaces, processes at the fresh water/seawater interface have only recently attracted attention of the researchers.
AN: 2970629

                                                                    771 of 1521  
TI: Evidence of recent lead pollution in Northeast Atlantic sediments.
AU: Tian,-Rucheng
AF: Inst. Estuarine and Coastal Res., East China Norm. Univ., Shanghai 200000, People's Rep. China
CO: 4. Chinese Oceanological and Limnological Science Conf. Qingdao, Shandong (People's Rep. China) (nd)
SO: PROCEEDINGS-OF-THE-4th-CHINESE-OCEANOLOGICAL-AND-LIMNOLOGICAL-SCIENCE-CONFERENCE.  DISICI-ZHONGGUO-HAIYANG-HUZHAO-KEXUE-HUIYI-LUNWENJI. Chinese-Soc.-of-Oceanology-and-Limnology,-Beijing-China BEIJING-CHINA SCIENCE-PRESS 1991. pp. 122-127
LA: Chinese
ER: M (Marine)
AB: It is now recognized that the biogeochemical cycle of lead in the open ocean is significantly perturbed by anthropogenic pollution. We collected seven cores in the Northeast Atlantic with an interface-corer of IGFA (France) in 1985. Atomic Absorption Spectrometry and Cathodic Stripping Voltammetry were used to determine lead concentration in sediments. Meanwhile one core was analyzed by sequential attaque to determine lead distribution in different forms of existence. Our results show that lead content is much higher in surficial sediments than below. The depth of sediments rich in lead is less than 1 cm in most cores and only 2 to 3 mm in cores 5 and 6. Sequential attaque analyses show that enrichment of lead in surficial sediments is caused by increase of labile Pb while conservative lead content has no evident changes.
AN: 2967132

                                                                    772 of 1521  
TI: ISHTAR, the project: An overview of Inner Shelf Transfer and Recycling in the Bering and Chukchi seas.
AU: McRoy,-C.P.
AF: Inst. Mar. Sci., Univ. Alaska, Fairbanks, AK 99775, USA
SO: CONT.-SHELF-RES. 1993. vol. 13, no. 5-6, pp. 473-479
LA: English
ER: M (Marine)
AB: ISHTAR was designed to study the impact of interannual variability of physical forcing on the cycle of carbon and nutrients in the shelf waters of the northern Bering and Chukchi seas. Anadyr Water is the nutrient source for high seasonal production in all trophic levels. Variations in transport of this water lead to variations in carbon fixation, deposition, and mineralization.
AN: 2962496

                                                                    773 of 1521  
TI: Rates of nitrification, distribution of nitrifying bacteria and inorganic N fluxes in northern Bering-Chukchi shelf sediments.
AU: Henriksen,-K.; Blackburn,-T.H.; Lomstein,-B.A.; McRoy,-C.P.
AF: Inst. Environ. Eng., Univ. Aalborg, Sohngaardsholmsvej 57, 9000 Aalborg, Denmark
SO: CONT.-SHELF-RES. 1993. vol. 13, no. 5-6, pp. 629-651
LA: English
ER: M (Marine)
AB: Spatial distribution of sediment nitrification rates and fluxes of ammonium and nitrate were measured in shelf sediments of the northern Bering and Chukchi seas. The sediments could be divided into three main areas depending on macrofaunal activity and input of organic nitrogen. Sediments underlying the highly productive Bering Shelf-Anadyr water (BSAS) were characterized by a high macrofaunal biomass and a high input of nitrogen-rich organic material. Tube-dwelling amphipods dominated in the sandy sediments of the northern Bering Sea, while bivalves dominated in the fine textured sediments of the Chukchi Sea. Sediments underlying the low productive Alaska Coastal Water (ACS) were characterized by low macrofaunal biomass and an input of lower quality organic material. Generally nitrification rates and nutrification potentials (NP) were highest in BASA and lower in ACS. Nitrification rates of surface sediment, calculated from NP, accounted for 90% of the measured rates in ACS, but only 35-75% in BSAS. These data together with the distribution patterns of NP and pore water nitrate profiles implied, that most sediment nitrification was confined to the sediment surface in ACS and in BSAS bivalve sediments, while most sediment nitrification took place in the ventilated burrow of BSAS amphipod sediments. The NH sub(4)@)u+ efflux was five-fold greater from BSAS compared to ACS, whereas the estimated sediment net NH sub(4) super(+) production was three-fold greater. The increase in NH sub(4)@)u+ efflux relative to net NH sub(4)@)u+ production could mostly be attributed to macrofaunal excretion. The NO sub(3)@)u- flux between sediment and water column was correlated with NO sub(3)@)u- concentrations in the bottom water. At concentrations higher than 10  mu M NO sub(3)@)u-, the flux was directed into the sediment and at lower concentrations out of the sediment. Spatial distribution of high bottom water NO sub(3)@)u- concentrations correlated with high NH sub(4)@)u+ fluxes out of the sediment. This resulted in a lower net efflux of inorganic nitrogen from these sediments.
AN: 2962346

                                                                    774 of 1521  
TI: Mediation of sulfur speciation by a Black Sea facultative anaerobe.
AU: Perry,-K.A.; Kostka,-J.E.; Luther,-G.W.,III; Nealson,-K.H.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: SCIENCE-WASH.. 1993. vol. 259, no. 5096, pp. 801-803
LA: English
AB: Shewanella putrefaciens , a respiratory facultative anaerobe isolated from the Black Sea, can reduce thiosulfate, sulfite, and elemental sulfur to sulfide readily and quantitatively. This widespread and anaerobically versatile microorganism, which is incapable of reducing sulfate, uses oxidized sulfur intermediates as electron acceptors during the respiratory oxidation of organic matter. Because of its widespread distribution and abundance, it may play a significant role in sulfur and trace metal cycling in the Black Sea and in other marine and freshwater anaerobic environments.
AN: 2962345

                                                                    775 of 1521  
TI: Seasonal and diel variation in the open ocean concentration of marine snow aggregates.
AU: Lampitt,-R.S.; Hillier,-W.R.; Challenor,-P.G.
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: NATURE. 1993. vol. 362, no. 6422, pp. 737-739
LA: English
ER: M (Marine)
AB: Marine snow, generally defined as aggregated particles of diameter greater than 0.5 mm, is thought to play an important role in oceanic biogeochemical cycles. Recent studies have focused on its unusual physical, biological and chemical properties but its temporal variability has received scant attention. The authors report observations of the abundance, volume concentration and size distribution of marine snow over a five-month period at a single site in the Northern Atlantic. At a depth of 270 m, marine snow particles demonstrated strong seasonal and diel variability. Volume concentrations in spring were about 20 times those in summer and autumn with late morning concentrations up to three times higher than at other times of the day. Our results suggest that the marine snow forms as a result of highly dynamic interactions in the particle pool. We believe that the mid-water biota and their migratory behaviour are responsible for the diel variability; they are therefore likely to have a significant influence on marine snow concentrations and hence on open-ocean material flux.
AN: 2960207

                                                                    776 of 1521  
TI: Spatial distribution, temporal sequence, and seasonal cycle of phytoplankton in reservoirs: Limiting and controlling factors.
OT: Distribuicao espacial, sequeencia temporal e ciclo sazonal do fitoplancton em represas: Fatores limitantes e controladores
AU: Tundisi,-J.G.
AF: Dep. Hidraul. e Saneamento Esc. Eng. Sao Carlos, Univ. Sao Carlos, Sao Carlos, SP, Brazil
SO: REV.-BRAS.-BIOL. 1990. vol. 50, no. 4, pp. 937-955
LA: Portuguese
ER: F (Freshwater)
AB: Artificial reservoirs are subjected not only to the climatological forcing functions that control or limit the seasonal cycle of phytoplankton and the biogeochemical cycles in aquatic ecosystems. The operation system produces an horizontal and unidirectional flux; these and the changing retention times are key factors that establish basic mechanisms for phytoplankton spatial distribution and succession. Physical forcing functions are thus fundamental in reservoirs. Pulse effects produced by climatological factors (precipitation, wind) coupled with water flux and discharge are key factors in the distribution of phytoplankton in time, and space. Spatial scales, include responses to changing turbulence conditions, patchiness associated with microscales in nutrient and temperature/conductivity/density characteristics of the water masses. The manipulation of these physical processes can be a valuable tool in the control of phytoplankton succession in reservoirs. Analysis of long term series of data can provide conditions for prognosis of the succession, distribution patterns, and interference in the ecosystem. Sampling programs have to be adapted to temporal/spatial scales of fluctuations and to microstructures in the systems. Specific examples for some key Brazilian reservoirs are given: the Lobo/Broa ecosystem-shallow meso oligotrophic - and the Barra Bonita reservoir - deeper eutrophic.
AN: 2959472

                                                                    777 of 1521  
TI: Organic matter in suspension and bottom sediments over the Guinea shelf.
OT: Organicheskoe veshchestvo vo vzvesi i donnykh otlozheniyakh shel'fa Gvinei
AU: Bezborodov,-A.A.; Burlakova,-Z.P.; Emel'-yanova,-O.V.
AF: MGI AN Ukr.S.S.R., Sevastopol', Ukraine
SO: EHKOL.-MORYA. 1991. no. 39, pp. 42-46
LA: Russian
ER: M (Marine)
AB: The patterns of suspended organic matter distribution over the shelf of Guinea during dry and wet seasons are considered and charts showing the distribution of organic carbon in the shelf sediments are provided. Effect of frontal upwelling zones and the tidal zone on the concentration and dispersion of organic matter in water and sediments is discussed.
AN: 2955517

                                                                    778 of 1521  
TI: Influence of temperature and substrate concentration on bacterial growth yield in Seine River water batch cultures.
AU: Barillier,-A.; Garnier,-J.
AF: CEMAGREF, 14 Ave. Saint-Mande, 75012 Paris, France
SO: APPL.-ENVIRON.-MICROBIOL. 1993. vol. 59, no. 5, pp. 1678-1682
LA: English
ER: F (Freshwater)
AB: The growth of natural bacterial assemblages was monitored in 3-liter reactors under various temperature and substrate concentration conditions. The oxygen concentration was continuously monitored, and subsamples were taken at short time intervals to determine bacterial number and biomass. The rate of bacterial mortality was also determined. Bacterial growth yield was calculated as the ratio of net production (increase in biomass corrected for mortality) to gross production (net production plus oxygen consumption expressed in carbon units). Averaging 33%, the growth yield did not show any trend with temperatures in the range of 8 to 25 degree C but increased with the concentration of dissolved organic carbon in the range of 2 to 12 mg of C/liter.
AN: 2953848

                                                                    779 of 1521  
TI: Laser microprobe mass analysis of Amazon Basin aerosols.
AU: Wouters,-L.; Hagedoren,-S.; Dierck,-I.; Artaxo,-P.; Van-Grieken,-R.
AF: Univ. Antwerp (UIA), Universiteitsplein 1, B-2610 Antwerp-Wilrijk, Belgium
SO: ATMOS.-ENVIRON.,-PART-A. 1993. vol. 27A, no. 5, pp. 661-668
LA: English
ER: F (Freshwater)
AB: Individual aerosol particles sampled over the Amazon Basin, Brazil, were analysed using laser microprobe mass analysis (LAMMA). Spectra are complex due to the high organic content of the samples. Phosphate was found to be concentrated largely in one particle type, which was only detected in the dry season samples. This points to a biomass burning origin or at least to a season-related vegetative aerosol production mechanism. The most abundant particle type, most likely originating from a vegetation source, can be described as a mixture of different salts and organic fragments.
AN: 2953004

                                                                    780 of 1521  
TI: Variations in aqueous sulfate concentrations at Panola Mountain, Georgia.
AU: Shanley,-J.B.; Peters,-N.E.
AF: U.S. Geol. Surv., P.O. Box 628, Monpelier, VT 05601, USA
SO: J.-HYDROL.-AMST.. 1993. vol. 146, no. 1-4, pp. 361-382
LA: English
ER: F (Freshwater)
AB: Aqueous sulfate concentrations were measured in incident precipitation, canopy throughfall, stemflow, soil water, groundwater, and streamwater at three locations in a 41 ha forested watershed at Panola Mountain State Park in the Georgia Piedmont. To evaluate the variations in sulfate concentrations, sampling intensity was increased during storms by automated collection of surface water and by incremental subsampling of rainfall, throughfall, and soil solution. Canopy throughfall, stemflow, and runoff from a bedrock outcrop in the watershed headwaters were enriched in sulfate relative to incident precipitation due to washoff of dry deposition that accumulated between storms. Soil waters collected from zero-tension lysimeters at 15 cm and 50 cm below land surface also were enriched in sulfate relative to precipitation, groundwater and streamwater. Sulfate concentrations in groundwater and in streamwater at base flow varied in an annual sinusoidal pattern with winter maxima and summer minima. Stream discharge and groundwater levels varied in a similar annual pattern in phase with the sulfate concentrations. The temporal variability of sulfate concentrations at most groundwater sites was small relative to the spatial variability among groundwater sites. Streamwater sulfate concentrations during base flow were controlled by low-sulfate groundwater discharge. As flow increased, an increasing proportion of shallow, high-sulfate groundwater and soil water contributed to streamflow. The dominant control on stream sulfate concentration shifted from sulfate retention by adsorption in the mineral soil at base flow to mobilization of sulfate from the upper, organic-rich horizons of the soil at high flow.
AN: 2951279

                                                                    781 of 1521  
TI: Mercury speciation in open ocean waters.
AU: Mason,-R.P.; Fitzgerald,-W.F.
AF: Dep. Mar. Sci., Univ. Connecticut, Avery Point, Groton, CT 06340, USA
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 779-789
LA: English
ER: M (Marine)
AB: Vital to our understanding of the biogeochemical cycling of Hg and the origin of the enhanced monomethylmercury (MMHg) concentrations in biota is knowledge of the sources, behaviour and fate of methylated Hg species in natural waters. Methylated Hg species, dissolved gaseous and reactive mercury were measured in the equatorial Pacific Ocean in early 1990. Both dimethylmercury (DMHg) and MMHg were found in the subthermocline waters of the equatorial Pacific Ocean. Maxima in alkylmercury species in the O sub(2) minimum region coincided with a decrease in reactive mercury. A significant inverse correlation between DMHg, and MMHg, concentration and O sub(2) content was observed. A maximum in reactive mercury was observed in the region of the thermocline, with similar concentrations in the surface and deeper waters.
AN: 2949032

                                                                    782 of 1521  
TI: Variations in mercury deposition to Antarctica over the past 34,000 years.
AU: Vandal,-G.M.; Fitzgerald,-W.F.; Boutron,-C.F.; Candelone,-J.-P.
AF: Dep. Mar. Sci., Univ. Connecticut, Avery Point, Groton, CT 06340, USA
SO: NATURE. 1993. vol. 362, no. 6421, pp. 621-623
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: POLAR ice contains a valuable record of past atmospheric mercury deposition, which can provide information about both the natural biogeochemical cycling of this toxic trace metal and the impact of recent anthropogenic emissions. But existing studies of mercury in polar ice and snow cores suffer from sample contamination and inadequate analytical procedures. Here we report measurements of mercury concentrations spanning the past 34,000 years from the Dome C ice core, Antarctica, using the stringent trace-metal clean protocols developed by Patterson and co-workers. Although this record does not extend into the industrial period, it provides an important baseline for future attempts to identify anthropogenic mercury in Antarctic ice and snow. We find that mercury concentrations were strikingly elevated during the last glacial maximum (18,000 years ago), when oceanic productivity may have been higher than it is today. As oceanic mercury emission is correlated with productivity, we suggest that this was the principal pre-industrial source of mercury to Antarctica; mercury concentrations in Antarctic ice might therefore serve as a palaeoproductivity indicator for the more distant past.
AN: 2941375

                                                                    783 of 1521  
TI: Carbon dynamics and sources in the Parana River.
AU: Depetris,-P.J.; Kempe,-S.
AF: SCOPE/UNEP Int. Carbon Unit, Inst. Biogeochem. und Meereschem., Univ. Hamburg, Bundesstr. 55, 2000 Hamburg 13, FRG
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 382-395
LA: English
ER: F (Freshwater)
AB: The Parana River was sampled and analyzed for carbon and mineral concentrations at the Parana-Santa Fe (Argentina) cross-section ( similar to 600 km above the mouth) between March 1981 and November 1984. Within this period, the Parana was affected by an extraordinary flood caused by the 1982 El Nino/Southern Oscillation (ENSO) climatic anomaly. Under such conditions, with a flow 75% higher than the long-term mean, the river exported a total organic C (TOC) load of 8.43 Tg/yr (3.0 g m super(-2)/yr) of which 89% was accounted for by dissolved organic C (DOC) and the remainder by particulate organic C (POC). Under normal hydrological conditions, however, the Parana has a TOC load that is roughly half of that determined during the ENSO-triggered flood (4.43 Tg/yr, 1.6 g m super(-2)/yr), but with a very different DOC:POC ratio (63:37). In July-August 1985 the Parana was sampled along a reach of over 1,300 km. At the time of sampling, the Paraguay River supplied  similar to 68% of the POC load, 59% of the labile particulate load (LPOC), and 71% of the DOC entering the middle reach of the Parana. Carbohydrates in LPOC appear to become more abundant that amino acids in the lower reaches, probably due a significant input from the floodplain of the Parana.
AN: 2940309

                                                                    784 of 1521  
TI: Uranium behavior in a permanently anoxic fjord: Microbial control?.
AU: McKee,-B.A.
AF: Louisiana Univ. Mar. Cent., Louisiana Univ. Mar. Consortium, 8124 Highw. 56, Cocodrie, LA 70344, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 408-414
LA: English
ER: M (Marine)
AB: Uranium contamination of groundwater resulting from U mining activities and the leak-age of nuclear waste from storage facilities is a growing concern. In Framvaren Fjord (southern Norway), dissolved  super(238)U concentrations at the bacterial maximum layer (24 m), which is situated a few meters below the oxic-anoxic (i.e. oxygen-hydrogen sulfide) interface (18 m), are observed to be  similar to 60% lower than concentrations above and below this depth. Removal of U occurs well below the depth at which Fe and Mn oxyhydroxides are precipitated and under conditions inconsistent with abiological reduction of soluble U(VI) to particle-reactive U(IV). Our observations suggest that the microbial population in the anoxic waters near the O sub(2)-H sub(2)S interface in the fjord exerts an effective control on the aquatic biogeochemistry of U in this environment.
AN: 2940272

                                                                    785 of 1521  
TI: Fish foraging behavior changes plankton-nutrient relations in laboratory microcosms.
AU: Novales-Flamarique,-I.; Griesbach,-S.; Parent,-M.; Cattaneo,-A.; Peters,-R.H.
AF: Dep. Biol., McGill Univ., Montreal, PQ, Canada
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 290-298
LA: English
ER: F (Freshwater)
AB: To demonstrate that the effects of higher trophic elements on plankton in laboratory aquaria are not simple top-down or bottom-up processes, we measured phosphorus and chlorophyll concentrations in replicated month-old aquaria undergoing one of five permutations involving three fish species, Daphnia pulex , and algae. Goldfish (Carassius auratus ) extirpated the Daphnia  and produced the highest observed algal and nutrient levels. Daphnia  persisted with armored catfish (Plecostomus hypostomus ) but algal levels were still high, even though total P concentrations of the water were lower. Angelfish (Pterophyllum scalare ) cropped all the Daphnia , but only moderate levels of algae resulted, apparently because these fish regenerate sedimented nutrients less effectively. Aquaria with neither fish nor Daphnia  supported even less algae, although total P concentration was not reduced. Finally, the water in aquaria with Daphnia , but no fish, had the lowest levels of both chlorophyll and total P. These gross changes were accompanied by shifts between the two dominant algal general, seemingly because higher levels of nutrient regeneration favor Scenedesmus  over Monoraphidium . Apparently, higher trophic elements affect lower ones directly, from above by modifying predation pressure and from below by changing the quantity and quality of regenerated nutrients, and indirectly by modulating competition within the plankton and between plankton and periphyton.
AN: 2940230

                                                                    786 of 1521  
TI: Rapid oxygen cycling in Trichodesmium thiebautii .
AU: Kana,-T.M.
AF: Horn Point Environ. Lab., P.O. Box 775, Cambridge, MD 21613, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 1, pp. 18-24
LA: English
ER: M (Marine)
AB: Oxygen uptake and evolution were measured in Trichodesmium thiebautii  trichomes with  super(18)O membrane inlet mass spectrometry. Samples were collected in the vicinity of the Bahamas Islands and eastern Caribbean Sea. Trichodesmium  exhibited high rates of oxygen uptake in the dark and in the light compared with previously studied cyanobacteria. Oxygen uptake in the dark averaged 23% of the maximum gross oxygen evolution rate and was suppressed minimally at low irradiances or after the addition of cyanide. Oxygen uptake in light increased between 50 and 200  mu Einst m super(-2)/s and was inhibited by 3-(3,4-)-dichlorophenyl)-1,1-dimethylurea (DCMU), indicating Mehler reaction activity. I estimate that 48% of the total photosynthetic linear electron flow went to oxygen reduction at moderate but nonsaturating irradiances. Light compensation points ranged from 50 to 300  mu Einst m super(-2)/s with values highest for midday samples. Rapid oxygen cycling may contribute to the protection of nitrogenase by reducing the oxygen tension within the cell or colony during oxygenic photosynthesis and by providing a mechanism (pseudocyclic photophosphorylation) for generating excess ATP for nitrogen fixation.
AN: 2940008

                                                                    787 of 1521  
TI: The influence of light intensity on dimethylsulfide production by a marine diatom.
AU: Vetter,-Y.-A.; Sharp,-J.H.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 419-425
LA: English
ER: M (Marine)
AB: The influence of light intensity on the production of the gas dimethylsulfide (DMS) by Skeletonema costatum  was studied in batch cultures. Culture pairs were grown under identical conditions except for light intensity. Cultures displayed a spike of dissolved DMS following inoculation and an increase in dissolved DMS during log phase and stationary phase. These increases were slower and less pronounced under reduced illumination. DMS production per cell declined throughout phase under reduced light, but remained constant throughout log phase under full illumination. The total mass of DMS produced under reduced light was less than half that produced under full illumination.
AN: 2939742

                                                                    788 of 1521  
TI: NOGAP B.6; Volume 9: Hydrocarbon determinations; Mackenzie River and Beaufort Sea
AU: Yunker,-M.B.; McLaughlin,-F.A.; Fowler,-B.R.; Brooks,-G.; Chiddell,-G.; Hamilton,-C.; Macdonald,-R.W.
CA: Institute of Ocean Sciences, Patricia Bay, Sidney, BC (Canada)
SO: CAN.-DATA-REP.-HYDROGR.-OCEAN-SCI. 1992 no. 60, 291 pp
NT: NTIS-Accession Number: MIC-93-02857/4.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: As part of the NOGAP B.6 program, with major objectives to determine hydrocarbon pathways and primary productivity of the waters overlying the Mackenzie shelf, the authors collected hydrocarbon samples in the Mackenzie Delta, from the Beaufort Sea coast and from repeat sampling of several transects extending from inshore waters to the shelf break. This report describes the analytical results for fractionated samples with concentrations reported for alkanes, alkenes, hopanes and other triterpenes, polycyclic aromatic hydrocarbons, alcohols and sterols. (DBO)
AN: 2936310

                                                                    789 of 1521  
TI: Flow and particulate nutrient removal by wetland with emergent macrophyte.
AU: Hosokawa,-Y.; Horie,-T.
AF: Port and Harbour Res. Inst., Minist. Transp., 1-1, 3-chome, Nagase, Yokosuka 239, Japan
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 1271-1282
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: Coastal wetland with emergent reed has the important function of settling particles in the flow. We undertook some experiments in order to ascertain the hydraulic characteristics of shallow surface flow in reed fields. The decline of water surface and the flow resistance coefficient were measured for low velocity in an experimental channel. Particle tracers were injected into the flow and the particle removal rate was calculated from the change of the particle concentration along the flow. The one-dimensional model with water level correction fits well to the data. The wetland system with reed will be a powerful means of eliminating particulate nutrient load in coastal areas.
AN: 2936226

                                                                    790 of 1521  
TI: Mechanisms of phosphorus released from the sediment-water interface in Xiamen Bay, Fujian, China.
AU: Wu,-Yuduan; Lin,-Yueling; Guo,-Tingzhong; Wang,-Longfa; Zheng,-Zhihong
AF: Inst. Environ. Sci., Xiamen Univ., Letter Box 99, Xiamen 361 005, Fujian, People's Rep. China
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 1087-1098
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: The concentrations of DRP (dissolved reactive phosphorus) in the estuary harbour waters along the coast of China are generally low, and the N/P ratios are much higher than the Redfield ratio. From Dalian Bay to the Zhujiang Estuary these ratios are as high as n/10-n/100. Field observations at the Jiulong Estuary and Xiamen Harbour in Fujian in recent years revealed that the high values of N/P ratios are 50-80 during April-October and 90-200 during November-March, respectively. A red tide of Skeletonema costatum  developed in Dalian Bay waters in the summer of 1988, where the N/P ratio was increased rapidly from 50 to 190, and reached as high a value as 340 at the end of the rampant algal propagation. This clearly indicates that phosphorus plays an important role in controlling eutrophication and red tide in China's marine coastal waters.
AN: 2935120

                                                                    791 of 1521  
TI: Significance of benthic regeneration in nutrient balance in the Bay of Cadiz, south-west Spain (a shallow semi-closed coastal ecosystem).
AU: Gomez-Parra,-A.; Forja,-J.M.
AF: Inst. Cienc. Mar. Andalucia (CSIC), Apdo. Ofic., 11510 Puerto Real (Cadiz), Spain
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 1079-1086
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: In this study, the first in situ measurements of nutrient benthic fluxes in the Cadiz Bay (south-west Spain) are presented. This zone, which receives a large input of organic matter from urban effluents, shows a progressive increase of both primary production and organic matter contents of sediments. A preliminary balance between benthic regeneration, phytoplankton consumption and nutrient tidal export suggests the importance of other nutrient sources in the zone, such as urban and industrial effluents, nitrogen fixation and rainfall.
AN: 2935104

                                                                    792 of 1521  
TI: The turnover of organic matter in hypertrophic sediments below a floating fish farm in the oligotrophic Gulf of Eilat (Aqaba).
AU: Angel,-D.; Krost,-P.; Zuber,-D.; Mozes,-N.; Neori,-A.
AF: Natl. Cent. Maricult., P.O. Box 1212, Eilat 88112, Israel
CO: Japanese-Israeli Symp. on Aquaculture, Haifa/Eilat (Israel), 2-8 Nov 1992
SO: ISR.-J.-AQUACULT.-BAMIDGEH. 1992. vol. 44, no. 4, pp. 143-144
NT: Abstract only.
LA: English
ER: M (Marine)
AB: The geochemistry and ecology of sediments below a floating fish farm, located near the North Beach of Eilat (Gulf of Aqaba), have been monitored during the past 2 years. The natural (undisturbed) sediment in this region is a fine alluvial sand that supports the seagrass Halophila  and endemic benthic fauna. Below the cage farm, the sediment is very fine-grained, organically enriched, and devoid of seagrasses and most of the endemic fauna. We have compiled a carbon budget for the cage farm and the region around it using measurements conducted at sea and data supplied by the fish farmers. The flux of particulate carbon deposited by the farm is approximately 7 g C/m super(2)/d, based on a daily food input of 1000 kg to the farm. The organic matter (OM) in the sediment is decomposed by both oxic and anoxic processes that account for removal of about 4.5 g C/m super(2)/d. Benthic degradation of OM (determined by H sub(2)S release rate, using flux chambers) was quite similar in both light and dark flux chambers in winter and spring. However, during summer and autumn, H sub(2)S production was very high in the dark flux chamber while there was no H sub(2)S production in the light flux chamber. We feel that these seasonal differences were due to the presence and activity of different benthic microbes. The rain of organic matter descending from the fish farm to the benthos was fairly constant throughout the study period. We found no net accumulation of organic matter in the sediment from October 1990 to May 1992, suggesting a balance between sedimentation and breakdown and/or removal of organic matter. Because sedimentation and decomposition rates showed that only 65% of the input carbon is removed by decomposition we propose that the remaining 35% is removed and/or degraded by a combination of strong bottom currents and as a result of feeding activity of native demersal fish. Furthermore, we suggest that the microbial mats play a number of important roles, including: a) mediating the mineralization of organic matter, b) controlling the flux of nutrients and gases (e.g. H sub(2)S and methane) out of the sediments, c) increasing the "surface tension" of the sediment surface and reducing the erosivity of the sediment.
AN: 2934846

                                                                    793 of 1521  
TI: Interactions between hydrodynamics and pelagic ecosystems: Relevance to resource exploitation and climate change.
AU: Legendre,-L.; Lefevre,-J.
AF: GIROQ, Dep. Biol., Univ. Laval, Quebec, PQ G1K 7P4, Canada
CO: Benguela Trophic Functioning Symp., (Cape Town) (South Africa), Sep 1991
SO: BENGUELA-TROPHIC-FUNCTIONING. Payne,-A.I.L.;Brink,-K.H.;Mann,-K.H.;Hilborn,-R.-eds. 1992. vol. 12 pp. 477-486
ST: S.-AFR.-J.-MAR.-SCI.-S.-AFR.-TYDSKR.-SEEWET. vol. 12
LA: English
ER: M (Marine)
AB: A proposal is made to classify the pools of biogenic carbon in the oceans by reference to their turnover times. Break points in the continuum of turnover times, located at 10 super(-2) and 10 super(2) years, distinguish between short-lived organic carbon, long-lived organic carbon and sequestered biogenic carbon. The three pools of biogenic carbon are discussed by reference to the more usual oceanographic concepts of new v. regenerated production, and export v. recycled production. Short-lived organic carbon is mainly associated with the microbial food-loop, long-lived organic carbon is relevant to renewable marine resources, and sequestered carbon is pertinent to global climate change (greenhouse effect). Recycling, export and sequestration are controlled by the proportions of primary production effects by small (< 5  mu m) and large (> 5  mu m) phytoplankton respectively, and by the selective grazing pressure experienced by cells in the various size-classes. These ecosystem processes are in turn governed by hydrodynamics. At low levels of auxiliary (mechanical) energy, the physical environment is stable, so that pelagic ecosystems are dominated by the microbial food-loop and biogenic carbon is mainly short-lived. Transitions from high levels of auxiliary energy to more stable conditions favour the production of large phytoplankton. When this takes place along predictable regular modes, primary production may be channelled into the long-lived pool, whereas stochastic transitions may lead to carbon sequestration. This theoretical framework may help the modern approaches of fisheries oceanography and biogeochemical oceanography to converge.
AN: 2934604

                                                                    794 of 1521  
TI: Bacterial sulfate reduction above 100 degree C in deep-sea hydrothermal vent sediments.
AU: Joergensen,-B.B.; Isaksen,-M.F.; Jannasch,-H.W.
AF: Max Planck Inst. Mar. Microbiol., Fahrenheistr. 1, 2800 Bremen 33, FRG
SO: SCIENCE-WASH.. 1992. vol. 258, no. 5089, pp. 1756-1757
LA: English
ER: M (Marine)
AB: The currently known upper temperature limit for growth of organisms, shared by a number of archaebacteria, is 110 degree C. However, among the sulfate-reducing bacteria, growth temperatures of greater than 100 degree C have not been found. A search for high-temperature activity of sulfate-reducing bacteria was done in hot deep-sea sediments at the hydrothermal vents of the Guaymas Basin tectonic spreading center in the Gulf of California. Radiotracer studies revealed that sulfate reduction can occur at temperatures up to 110 degree C, with an optimum rate at 103 degree  to 106 degree C. This observation expands the upper temperature limit of this process in deep-ocean sediments by 20 degree C and indicates the existence of an unknown group of hyperthermophilic bacteria with a potential importance for the biogeochemistry of sulfur above 100 degree C.
AN: 2934510

                                                                    795 of 1521  
TI: Environmental systems, an introductory text. Second edition.
AU: White,-I.D.; Mottershead,-D.N.; Harrison,-S.J.
SO: NEW-YORK,-NY-USA CHAPMAN-AND-HALL 1992. 616 pp
NT: Price: $39.95 (USA); $49.55 (Canada), paperback.
LA: English
AB: This introductory text is an integrated and unified account of systems on all scales from planetary to molecular. Using energy flow and mass transfer as unifying themes, the discussion is set in a thermodynamic perspective. The concepts and terminology of the systems approach are dealt with in full. The approach is based on a nested hierarchy of systems in which human-environment interactions and the functional connections within them and between them are dealt with. For the second edition, all chapters have been revised. In part B, there is a new chapter on the hydrosphere dealing with the effect of the oceans of the energetics and biochemistry of the planet. The biosphere and ecosphere chapters have been condensed into one, with more emphasis on the nature of human interference in biogeochemical cycles. There are new chapters on eolian systems and on coastal systems. There is also new material on landscape ecology and climatic change, including the effect of ozone holes.
AN: 2933929

                                                                    796 of 1521  
TI: The role of sesarmid crabs in the mineralization of leaf litter of Rhizophora apiculata  in a mangrove, southern Thailand.
AU: Poovachiranon,-S.; Tantichodok,-P.
AF: Phuket Mar. Biol. Cent., P.O. Box 60, Phuket 83000, Thailand
SO: RES.-BULL.-PHUKET-MAR.-BIOL.-CENT. 1991. no. 56, pp. 63-74
LA: English
ER: M (Marine)
AB: Data of leaf fall within 28 weeks are reported from a mangrove forest at Ao Nambor, Phuket, Thailand. The analysis of foregut contents of 5 species of sesarmid crabs (Neoepisesarma  and Chiromanthes  spp.) indicates that they are primarily herbivores. Consumption rate experiments and preference rate experiments in aquaria showed that brown and green leaves were preferred food sources for sesarmid crabs. Leaf removal by sesarmid crabs in mangrove forest indicated very large variations in feeding activity. Chemical composition of green, yellow and brown leaves of Rhizophora apiculata  were analysed.
AN: 2933203

                                                                    797 of 1521  
TI: Photochemical studies of the Eastern Caribbean: An introductory overview.
AU: Zika,-R.G.; Milne,-P.J.; Zafiriou,-O.C.
AF: Rosenstiel Sch. Mar. Atmos. Sci., Univ. Miami, Miami, FL, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1993. vol. 98, no. C2, pp. 2223-2232
NT: Photochemistry of Eastern Caribbean waters.
LA: English
ER: M (Marine); B (Brackish)
AB: This special section of the Journal of Geophysical Research reports a multi-investigator study of a number of sunlight-initiated photoprocesses taking place in the varied biogeochemical and oceanographic environment found in the tropical Eastern Caribbean and Orinoco River delta in the spring and fall of 1988. Principal conceptual themes that were addressed by the program included (1) the characterization of the role of dissolved organic matter as the main chromophore initiating photoprocesses in surface seawater, (2) the determination of the fluxes and pathways of reactants and transient species involved in oxygen photoredox chemistry, and (3) the continuing development of chemical mapping strategies, including observing and modelling reactive phototransient distribution in terms of their sources, mixing, and fates. Ancillary supporting studies included observation of water mass tracers, dissolved trace gases, atmospheric components, nutrients and the geochemistry of estuarine mixing processes in an important continental margin. The observational and mechanistic investigations reported here feature a number of novel or improved methods allied with some advanced underway sampling, sensing and computing facilities that were implemented aboard the R/V Columbus Iselin . Results from the study showed large-scale (-1000 km) seasonal variations in surface water photoreactivity, optical and biooptical characteristics over much of the Caribbean Basin. These changes resulted from seasonally varying riverine inputs of organic chromophores, nutrients and suspended material. Smaller scale (10-100 km) studies carried out in the Orinoco delta and the Gulf of Paria showed that estuarine mixing processes did not affect major net removal of dissolved organic matter, consistent with the hypothesis that riverine chromophore input plays a dominant role in open-water photochemistry.
AN: 2932983

                                                                    798 of 1521  
TI: Nitrogen and phosphorus compounds in bottom sediments: Mechanisms of accumulation, transformation and release.
AU: Martinova,-M.V.
AF: Inst. Water Problems, Sadovo-Chernogriazskaja 13/3, 103064 Moscow, Russia
SO: HYDROBIOLOGIA. 1993. vol. 252, no. 1, pp. 1-22
NT: Spec. Iss.: Sediment-Water Interaction 4.
LA: English
ER: F (Freshwater)
AB: This paper is an overview of Russian literature dealing with the accumulation, the transformations and the release of phosphate and nitrogen compounds in a great number of Russian lakes and reservoirs. A considerable data bank has been analysed. Special attention is given to the relation of N- and P- accumulation with the input and transformation of organic carbon, as well as to the release mechanisms, often in relation to eutrophication of the lakes and reservoirs. It is shown that the major input of organic matter into the sediments comes from autochthonous material, and is usually > 70%. The relative importance of phytoplankton and macrophytes as sources of organic matter is discussed; it appears that trophic state, depth and other factors may have a large influence on this ratio. In shallow eutrophic lakes macrophytes may be the source of organic matter, which source can amount to 1.5-2.5 times that of phytoplankton. It is also shown that the C/N ratio is not a good indicator of the source of the organic matter, because their C/N ratios often are not very different. The decomposition rate of organic matter was analysed; it depends on trophic state and other factors.
AN: 2932721

                                                                    799 of 1521  
TI: Manganese dynamics in surface waters of the eastern Caribbean.
AU: Waite,-T.D.; Szymczak,-R.
AF: Australian Nuclear Sci. Technol. Org., Menai, N.S.W., Australia
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1993. vol. 98, no. C2, pp. 2361-2369
NT: Photochemistry of Eastern Caribbean waters.
LA: English
ER: M (Marine)
AB: The rate of photoreductive dissolution of manganese oxide in eastern Caribbean waters appears to be relatively rapid with an approximate linear dependency of dissolution rate on organic content of these waters. From the magnitude of derived absolute dissolution rates it would appear that reductive rather than oxidative processes should dominate transformations of manganese in surface waters though further insight into the reactivity of "naturally occurring" oxides is needed. Oxidation of Mn(II) added to surface water samples is observed and occurs at rates between those observed for coastal and open ocean surface waters by other investigators. Obvious correlations between oxidation rates and water column characteristics such as total bacterial numbers, dissolved (or particulate) manganese concentrations or organic content of surface waters are not evident. Transformations of manganese in the surface waters of the eastern Caribbean appear to be masked by the supply of fresh particulate material presumably, in part at least, from the Orinoco River.
AN: 2932681

                                                                    800 of 1521  
TI: The impact of desiccation of a freshwater marsh (Garcines Nord, Camargue, France) on sediment-water-vegetation interactions. Part 1: The sediment chemistry.
AU: Groot,-C.-J.-de; Wijck,-C.-van
AF: Assoc. "Leiden-Camargue", c/o Stn. Biol. Tour du Valat, Le Sambuc, 13200 Arles, France
SO: HYDROBIOLOGIA. 1993. vol. 252, no. 1, pp. 83-94
NT: Spec. Iss.: Sediment-Water Interaction 4.
LA: English
ER: F (Freshwater)
AB: The impact of desiccation on a marsh sediment was studied both in the laboratory and in the field. Changes in the sediment chemistry of a homogenized sediment suspension during desiccation were studied in the laboratory. FeS was oxidized completely. A considerable mineralization of organic phosphate took place, from both the acid soluble organic phosphate fraction and from the residual organic phosphate fraction, but no significant mineralization of organic matter was observed. The o-P formed during the mineralization was recovered partly in the Fe(OOH) approximately equals P fraction and partly in the CaCO sub(3) approximately equals P fraction. An upward flux was found. During spring and summer 1990 the water inlet to a shallow permanent freshwater marsh with an surface of about 1.5 hectares was blocked, in order to desiccate the marsh by evaporation. The sediments initially consisted of a black anoxic organic top layer and a less organic anoxic gray layer. During the desiccation of the sediment a brown oxic surface layer was formed from the black layer and an increase of pH and Eh occurred. Subsequent rainfall made the Eh increase further but caused a decrease in pH indicating an increase in bacterial activity. Drying may be utilized as a tool, in wetland management, to eliminate organic nitrogen and carbon from the sediment. In rice culture, it may be used to make part of the organic nitrogen available to the rice.
AN: 2932589

                                                                    801 of 1521  
TI: The role of Gloeotrichia echinulata  in the transfer of phosphorus from sediments to water in Lake Erken.
AU: Pettersson,-K.; Herlitz,-E.; Istvanovics,-V.
AF: Uppsala Univ., Inst. Limnol., Erken Lab., Norr Malma 4200, S-761 73 Norrtaelje, Sweden
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 123-129
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: The abundance of Gloeotrichia echinulata  colonies in the sediments of Lake Erken and their phosphorus content were investigated to determine the contribution of Gloeotrichia  colonies to total sediment phosphorus. Moreover, the potential size of the algal inoculum and the migration to the water during summer were estimated. The surplus phosphorus content of the resting colonies in the sediment was about 45% of total phosphorus, which maximized at 8.5  mu g P/(mg dw)  or 81  mu g P/colony. The C:P ratio (by weight) in the early colonies appearing in the lake water was 50:1, while the ratio stabilized at 150 during the major migration period. The internal supply of surplus phosphorus was used during the pelagic growth of the colonies. The internal phosphorus loading to the epilimnion of Lake Erken due to Gloeotrichia  migration could, from the measurements of the increase in particulate epilimnetic phosphorus, be estimated at 40 mg P/m super(2) or 2.5 mg P/m super(2)/d in late July and early August. Determination of the number of colonies in the sediment before and during the migration verified this value to be a conservative estimate of the internal phosphorus loading due to Gloeotrichia) migration to the epilimnion in Lake Erken. The sediment P content calculated from the P concentration in early epilimnion colonies resulted in a value of 35  mu g P/(g dw) as a maximum. This corresponds to only 3% of the total phosphorus content in Lake Erken sediment.
AN: 2932310

                                                                    802 of 1521  
TI: The role of microorganisms in mobilization and fixation of phosphorus in sediments.
AU: Gaechter,-R.; Meyer,-J.S.
AF: Inst. Aquat. Sci. (EAWAG), Swiss Fed. Inst. Technol (ETH), CH-6047 Kastanienbaum, Switzerland
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 103-121
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: Cycling of phosphorus (P) at the sediment/water interface is generally considered to be an abiotic process. Sediment bacteria are assumed to play only an indirect role by accelerating the transfer of electron from electron donors to electron acceptors, thus providing the necessary conditions for redox- and pH-dependent, abiotic sorption/desorption or precipitation/dissolution reactions. Results summarized in this review suggest that in eutrophic lakes, sediment bacteria contain as much P as settles with organic detritus during one year, in oligotrophic lakes, P incorporated in benthic bacterial biomass may exceed the yearly deposition of bioavailable P several times, storage and release of P by sediment bacteria are redox-dependent processes, an appreciable amount of P buried in the sediment is associated with the organic fraction, sediment bacteria not only regenerate PO sub(4), they also contribute to the production of refractory, organic P compounds, and in oligotrophic lakes, a larger fraction of the P settled with organic detritus is converted to refractory organic compounds by benthic microorganisms than in eutrophic lakes. From this we conclude that benthic bacteria do more than just mineralize organic P compounds. Especially in oligotrophic lakes, they also may regulate the flux of P across the sediment/water interface and contribute to its terminal burial by the production of refractory organic P compounds.
AN: 2932261

                                                                    803 of 1521  
TI: P-flux regulation in sediments by transport processes.
AU: Ripl,-W.
AF: TU-Berlin, Inst. Oekol., Fachgebiet Limnol., FRG
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 218
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Lake internal phosphorus-recycling from sediments is a significant process in most eutrophic shallow lakes. The mechanisms for P-liberation in the sediments are coupled microbial processes depending on water transport at the sediment-water interface. Thereby electron acceptors are supplied to sessile microassemblages of bacteria and inhibitory products, such as hydrogen sulphide, are removed by water transport. This relations where shown by time series in interstitial water strata and lake-budget calculations for several lakes in the Berlin-region, the Schlei-estuary and Swedish lakes. In shallow eutrophic lakes up to 1 g/m super(2)/month phosphorus have been liberated by the process of internal fertilisation from sediments during short periods in summer and autumn. This was equal to the whole phosphorus content of the upper 2 mm of surface sediments and resulted in a large increase of phosphate concentration in water column. The periods of internal P-liberation where coupled with high rates of plankton sedimentation and depleted oxidized nitrogen by denitrification in sediment surface. In these periods desulfurication became the main respiration-process in sediment metabolism. The sediment studies showed a monocausal hierarchy of processes. The energyflow partly resulting in water transport and in chemical reactions control the sediment metabolism with respect to space and time distribution of microbial activity.
AN: 2932200

                                                                    804 of 1521  
TI: The role of microbial processes in the phosphorus flux regulation between sediments and water.
AU: Sinke,-A.J.C.; Cottaar,-F.H.M.; Buis,-K.; Keizer,-P.
AF: Limnol. Inst., Rijsstraatweg 6, 3631 AC Nieuwersluis, Netherlands
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 218
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: B (Brackish)
AB: In aquatic sediments the mineralization of organic matter regenerates phosphates, resulting in an accumulation of phosphates in the interstitial water and the formation of a concentration gradient. The subsequent diffusive transport to the overlying water is affected by chemical and microbial processes. Especially the redox state of the sediment is known to be an important factor determining the actual phosphate flux. The presence of an oxidized microlayer at the sediment surface is considered to be an important trap for phosphates. The high adsorption capacity of the oxidized microzone is generally ascribed to the presence of iron(III)-hydroxides. Lately, also the role of microorganisms has come into focus. Microorganisms in the surface layer of the sediment might act as a redox dependent source/sink mechanism of phosphates. This contribution is focused on the role of methane oxidizing bacteria in the sediment surface. In Lake Loosdrecht almost the entire methane flux diffusing upward is oxidized in the sediment surface layer. In periods with high methane production the major fraction of the oxygen consumption of the sediment can be ascribed to methanotrophic bacteria. An experimental setup will be described which enabled us to manipulate the methane flux toward the sediment surface. Microelectrode equipment was used to quantify the oxygen consumption and tThe oxygen penetration depth. In columns with high activity of methanotrophic bacteria a decrease in the oxygen penetration depth could be demonstrated. However, these columns appeared to have a higher phosphate adsorption capacity than the controls. Batch experiments were conducted to examine the role of methanotrophic bacteria in the uptake of phosphates.
AN: 2932066

                                                                    805 of 1521  
TI: Phosphate compounds in sediments. 2. Organic aspects.
AU: Groot,-C.J.-de; Golterman,-H.L.
AF: Stn. Biol., Tour du Valat, Arles 13200, France
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 100
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Although org-P accounts for a large part of the P sub(sed), little is known about its chemical and biological properties. In most studies investigating the chemical nature of org-P sub(sed) compounds, only a small percentage could be characterized. Of the compounds found phytic acid and related compounds were quantitatively the most important. In this study three different approaches have been combined, to study the properties of org-P sub(sed): (1) The complex and adsorption chemistry of phytic acid and its bioavailability were studied in laboratory experiments. (2) Algae were killed and left to mineralize in an "artificial" sediment. The properties of the remaining organic phosphate compounds were investigated. (3) After removal of Fe(OOH)  approximately equals  P and CaCO sub(3)  approximately equals  P, the remaining org-P was studied on Camargue sediments. An attempt was made to characterize the nature of ASOP (Acid Soluble Org-P). Phytic acid was found to form complexes with Ca super(2+), Mg super(2+), Mn super(2+), Fe super(2+) and Fe super(3+). The Fe complexes were found to be the most stable in the presence of chelating agents. All complexes dissolved in diluted acid.
AN: 2932060

                                                                    806 of 1521  
TI: Considerations in modeling the sediment-water exchange of phosphorus.
AU: Lijklema,-L.
AF: Nat. Conserv. Dep., Agric. Univ., P.O. Box 8080, 6700 DD Wageningen, Netherlands
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 219-231
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: The potential to release accumulated phosphorus from sediments has been the major motive to study and to model the fate of this nutrient in sediments. For the dynamics of the sediment-water interaction the sizes of the pools involved and the rates of conversion/transport from one pool to another are of primary interest. As the sediment pools for phosphate are generally much larger than the pools in the water column, a rather slow adjustment of the sediment to management measures will occur. For the analysis of management measures it is obvious that the gradual change in sediment composition must be taken into account. Only for rather short periods the sediment composition can be assumed to be constant; this may be appropriate for studies of e.g. the annual cycle. The sediment-water interaction is a complex resultant of physical, chemical and biological processes. Aspects which are discussed and need to be considered in application of a model in research or management are the level of aggregation and detail that is required and may still be practical, the spatial and temporal scales which are applicable for the processes mentioned and their influence upon the numerical dispersion and model stability, the availability of data for calibration/validation and the resolution of the analytical techniques. These aspects are not independent however. Frequently models are not functional because they contain details which are either unnecessary or suggest a feigned accuracy which is not justified by analytical and experimental resolution of system characteristics.
AN: 2932058

                                                                    807 of 1521  
TI: Phosphate compounds in sediments. 1. Inorganic and biological aspects.
AU: Golterman,-H.L.; Graaf,-I.M.-de; Groot,-C.J.-de
AF: Stn. Biol., Tour du Valat, Arles 13200, France
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;van-Raaphorst,-W.-eds. 1993. vol. 253, no. 1-3 pp. 99-100
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: The chemical adsorption of phosphate onto sediments may be caused by Fe(OOH) and/or CaCO sub(3). Mathematically the adsorption can be described by a Langmuir or a Freundlich isotherm. Analyzing several chemical reaction mechanisms for the equilibrium between (o-P) sub(w) and P sub(sed) leads, under certain conditions, to the Freundlich isotherm, and the best description that can be proposed at the moment is P sub(sed) = A super(*)(o-P) sub(w) super(0.33) with A being a negative, nearly linear function of the pH. The constant "A" does not depend only on the pH; compounds like NaCl, MgCl sub(2) and CaCl sub(2) etc. influence "A" strongly. We think that ion activities cause this effect through the electric double layer of the Fe(OOH). A different effect is caused by the presence of S super(2-), which renders the Fe(OOH) inactive. This inactivation can be undone by denitrification. The adsorption onto CaCO sub(3) can be explained by the soluble Ca super(2+) concentration, which causes the product formed (probably apatite) to be co-precipitated with CaCO sub(3). A range of values for the solubility product of apatite is proposed. Data from the rivers Rhine and Rhone suggest a value near 10 super(-50). The Ca and Fe phosphate adsorption mechanisms can be combined to a solubility diagram, of which a new numerical version will be presented. Sediments from about 10 lakes have been analyzed for FeOOH  approximately equals  P and CaCO sub(3)  approximately equals  P using sequential extractions with Ca-NTA and Na-EDTA. Furthermore the bioavailability of the P sub(sed) for the alga Scenedesmus  sp. was measured in bioassays. Bioavailability was compared with the different fractions. It appeared that especially the sum of the FeOOH  approximately equals  P and CaCO sub(3)  approximately equals  P fractions was available, while "org-P" was not available.
AN: 2932031

                                                                    808 of 1521  
TI: Phosphorus composition and release in sediment bacteria of the genus Pseudomonas  during aerobic and anaerobic conditions.
AU: Waara,-T.; Jansson,-M.; Pettersson,-K.
AF: Inst. Limnol., Univ. Uppsala, Box 557, S-75122 Uppsala, Sweden
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 131-140
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: A substantial amount of sediment phosphorus can be bound in bacterial biomass. In this study the fractional composition of phosphorus in the bacteria Pseudomonas  was determined by sequential extraction with ammonium chloride, sodium hydroxide and hydrochloric acid according to the scheme of Hieltjes & Lijklema (1980). Both non-labelled and  super(32)P-labelled bacteria were used for fractionation. Up to 80% of the bacteria phosphorus was found in the NaOH-nRP fraction, which is in agreement with the results of Hupfer & Uhlman (1992) for Acinetobacter  and activated sludge obtained with the sequential extraction scheme of Psenner et al. (1985). A significant correlation was found between bacterial biomass and the amount of phosphorus retained in the NaOH-nRP fraction when sediments were fractionated. Additional experiments with  super(32)P-labelled Pseudomonas  in sediment-water systems were performed in order to follow bacterial release of phosphorus under aerobic and anaerobic conditions. These studies did not sustain the hypothesis that anaerobic conditions lead to rapid release of phosphorus from bacterial cells.
AN: 2931981

                                                                    809 of 1521  
TI: The effect of deposition of organic matter on phosphorus dynamics in experimental marine sediment systems.
AU: Slomp,-C.P.; Van-Raaphorst,-W.; Malschaert,-J.F.P.; Kok,-A.; Sandee,-A.J.J.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Van-Raaphorst,-W.-eds. 1993. vol. 253, no. 1-3 pp. 83-98
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: M (Marine)
AB: The effect of deposition of organic matter on phosphorus dynamics in sandy marine sediments was evaluated using an experimental system (boxcosms) and three different strategies: (1) no supply (2) one single addition (3) weekly additions of a suspension of algal cells (Phaeocystis  sp.). Macrofauna (3 species, 6 individual of each) were added to half of the boxes. Both in the case of the single and weekly additions a clear effect of increased organic matter loading on phosphorus dynamics was found. Following the organic matter addition, porewater phosphate concentrations in the upper sediment layer increased, phosphate release rates from the sediment increased by a factor 3-5 and in the boxes to which a single addition was applied NaOH-extractable phosphorus increased substantially. The increase in phosphate release rates from the sediment was attributed to mineralization of the added material and to direct release from the algal cells. No clear effect of the presence of macrofauna on sediment-water exchange of phosphate could be discovered. The macrofauna were very effective at reworking the sediment, however, as illustrated by the organic carbon profiles. It is hypothesized that the sediment-water exchange rates of phosphate were regulated by the layer of algal material which was present on the sediment surface in the fed boxes. In the boxes to which the single addition was applied porewater phosphate concentrations were lower and NaOH-extractable phosphorus was higher in the presence of macrofauna, suggesting that macrofauna can stimulate phosphate binding in the sediment.
AN: 2931979

                                                                    810 of 1521  
TI: The relative importance of biological and chemical processes in the release of phosphorus from a highly organic sediment.
AU: Montigny,-C.-de; Prairie,-Y.T.
AF: Dep. Sci. Biol., Univ. Quebec, C.P. 8888 Succ. A, Montreal, PQ H3C 3P8, Canada
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 141-150
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: Bacteria can play an important role in the process of anaerobic phosphorus release: they can act as a direct source of orthophosphates, or as a catalyst of iron hydroxide reduction. We studied their influence on phosphorus release from highly organic sediments of a Canadian shield lake. Phosphorus and iron release were measured under aerobic and anaerobic conditions, with or without sterilization, and at different pH. We measured also the abundance and activity of bacteria in sediments. The increased P release after sterilization can be explained by cell lysis. Compared to sterilization, changing oxygen concentrations or acidification had little or no effect on P release. In these sediments, phosphorus and iron movements were independent. Most of the total dissolved iron seemed to be linked to humic acids, but not phosphorus.
AN: 2931963

                                                                    811 of 1521  
TI: Transformations between organic and inorganic sediment phosphorus in Lake Balaton.
AU: Istvanovics,-V.
AF: Balaton Limnol. Res. Inst., Hungarian Acad. Sci., H-8237 Tihany, Hungary
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 193-206
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: In order to estimate microbial P content and biological P uptake in sediments, the tungstate precipitation method of Orrett & Karl (1987) was used in sediment extracts. This method allows a simple and rapid separation of organic and inorganic  super(32)P radioactivity. Either inorganic  super(32)P (as carrierfree H sub(3) super(32)PO sub(4)) or organic  super(32)P (as  super(32)P-labelled algal material) was added to surface sediment suspensions of shallow Lake Balaton. Inorganic  super(32)P was rapidly transformed into organic  super(32)P, and this process was completely inhibited by formaline. P content of living benthic microorganisms was estimated from steady state distribution of the radioactivity. Transformation of algal organic P into inorganic P could also be detected. In extremely P limited Lake Balaton benthic microorganisms were shown to supplement their high P requirements by inorganic P uptake. The velocity of the inorganic into organic P transformation, i.e. the rate of microbial P uptake, was comparable to P uptake in the water column. Microbial P uptake contributed significantly to total P fixation by sediments, particularly at low ( less than or equal to  100  mu g P/l) phosphate additions.
AN: 2931942

                                                                    812 of 1521  
TI: Proceedings of the Third International Workshop on Phosphorus in Sediments.
AU: Boers,-P.C.M.; Cappenberg,-Th.E.; van-Raaphorst,-W.-(eds.)
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: HYDROBIOLOGIA. 1993. vol. 253, no. 1-3, 376 pp
LA: English
AB: The phosphorus cycle in aquatic environments has been a scientific topic for several decades. To quote Hutchinson "Of all the elements present in living organisms, phosphorus is likely to be the most important ecologically." Although this statement may need some differentiation, it clearly points to the basic reason for scientific interests. In limnology most studies focused on the mobilization and (bio)-availability of phosphorus. The first limnologists who recognized the importance of iron-phosphorus interactions and the coupling between mobilization and redox conditions were Einsele and Mortimer. Their observations form the basis of many studies carried out nowadays. Many of these studies concern the precise nature of iron-phosphorus bindings in sediments and suspended matter and their effect on the phosphorus buffering system, i.e. the ability of the sediments to constrain phosphate concentrations within narrow limits. The sorptive properties of soil minerals were first investigated by agronomists and soil scientists to assess "phosphate fixation" which makes part of the phosphorus applied in fertilizers unavailable to plants. In sediment-water systems phosphate fixation is studied to determine the long-term loss of phosphorus from the ecosystem to the sediments. Soil scientists also initiated the development of reliable sequential extraction schemes to distinguish between phosphorus compounds bound to different complexes and minerals.
AN: 2931787

                                                                    813 of 1521  
TI: P-flux regulation in sediments by coupled microbial processes.
AU: Heller,-S.
AF: Ges. Gewaesserbewirtsch., Berlin, FRG
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 217
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Lake internal phosphorus-recycling from sediments is a significant process in most eutrophic shallow lakes. The mechanisms for P-liberation in the sediments are coupled microbial processes depending on water transport at the sediment-water-interface. Thereby electron acceptors are supplied to sessile microassemblages of bacteria and inhibitory products, such as hydrogen sulphid, are removed by water transport. Laboratory experiments with extractions of phosphorus by addition of hydrogen sulphid as reference (complete liberation of ironbound phosphorus) or by addition of glucose, iron and sulfate in different molar relation revealed the reaction mechanisms for various sediment types. The sediment studies showed a monocausal hierarchy of processes. The energyflow partly resulting in water transport and in chemical reactions control the sediment metabolism with respect to space and time distribution of microbial activity.
AN: 2931776

                                                                    814 of 1521  
TI: Sulfate control of phosphorus availability in lakes. A test and re-evaluation of Hasler and Einsele's model.
AU: Caraco,-N.F.; Cole,-J.J.; Likens,-G.E.
AF: Inst. Ecosyst. Stud., New York Bot. Garden, Millbrook, NY 12545, USA
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 275-280
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: During summer stratification large amounts of phosphorus (P) accumulate in anoxic bottom waters of many lakes due to release of P from underlying sediments. The availability to phytoplankton of this P is inversely related to the Fe:P ratio in bottom waters. Using data from 51 lakes, we tested the hypothesis that sulfate concentration in lake water may be critical in controlling the Fe:P ratio in anoxic bottom waters. Results showed that Fe:P ratios in bottom waters of lakes were significantly (p < 0.001) related to surface water sulfate concentrations. The higher Fe:P ratios in low sulfate systems is due not only to higher iron concentrations in anoxic bottom waters but also to lower P concentrations in anoxic waters. Thus, our results suggest that anthropogenically induced increases in sulfate concentrations of waters (e.g. from fossil fuel burning) may have a double effect on P cycling in lakes. Higher sulfate concentrations can both increase the magnitude of P release from sediments as well as increase the availability of P released from sediments into anoxic bottom waters.
AN: 2931735

                                                                    815 of 1521  
TI: (The influence of osmoregulation systems on the survival and adaptation of enteric bacteria in the marine environment.).
OT: Influence des systemes d'osmoregulation sur la survie et l'adaptation des bacteries enteriques dans l'environnement marin
AU: Gauthier,-M.J.
AF: INSERM, Unite 303 "Mer et Sante," 1 av. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991.  CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991 UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. no. 63 pp. 1-15
ST: MAP-TECH.-REP.-SER. no. 63
LA: French
ER: M (Marine)
AN: 2924830

                                                                    816 of 1521  
TI: Biogeochemical cycles of specific pollutants (activity K). Survival of pathogens. Final reports on research projects (1989-1991).
OT: Cycles biogeochimiques de polluants specifiques (activite K). Survie des pathogenes. Rapports finaux sur les projets de recherche (1989-1991)
CA: UNEP Mediterranean Action Plan, Athens (Greece)
WHO, Geneva (Switzerland)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1992. no. 63, 85 pp
LA: French
ER: M (Marine)
AN: 2924820

                                                                    817 of 1521  
TI: Comparative study of the adsorption of organic ligands on aluminum oxide by titration calorimetry.
AU: Benoit,-P.; Hering,-J.G.; Stumm,-W.
AF: Dep. Civ. Eng., 4173 Engineering I, Univ. California, Los Angeles, CA 90024-1593, USA
SO: APPL.-GEOCHEM. 1993. vol. 8, no. 2, pp. 127-139
LA: English
ER: F (Freshwater)
AB: Ligand adsorption on  delta -Al sub(2)O sub(3) at pH 8 was examined for a series of organic ligands (aromatic acids, monochlorophenols and aliphatic acids) including both monodentate and bidentate ligands. Adsorption isotherms for the aromatic acids exhibited saturation at high dissolved ligand concentrations; saturation was not observed (over the concentration range examined) for the chlorophenols. Small, though measurable, amounts of heat were evolved on reaction of the aromatic acids, the monochlorophenols and propionate (but not of the longer chain fatty acids) with the oxide surface; overall ligand adsorption reactions were exothermic ( Delta H sub(obs) < 0). For adsorption of (partially or fully) protonated ligands, the favorable  Delta H sub(obs) was due largely to the exothermic proton transfer reaction between phenolic hydroxyl groups of the ligands and hydroxide ions displaced from the oxide surface. The enthalpy corresponding to the ligand-exchange reaction of surface hydroxyl groups for the various ligands (as fully deprotonated species),  Delta H sub(corr), appeared to be related to the ligand structure. The surface ligand-exchange reaction was more exothermic for the dicarboxylic acid phthalate than for the monocarboxylic acids benzoate or propionate or for salicylate and was endothermic for the chlorophenols.
AN: 2923952

                                                                    818 of 1521  
TI: The role of macrophytes in phosphorus turnover: Sources and sinks.
AU: Waisel,-Y.; Oertli,-J.J.; Stahel,-A.
AF: Dep. Bot., Tel Aviv Univ., Tel Aviv 69978, Israel
CO: 8. Int. Symp. on Aquatic Weeds, Uppsala (Sweden), 13-17 Aug 1990
SO: 8th-INTERNATIONAL-SYMPOSIUM-ON-AQUATIC-WEEDS.-SWEDISH-UNIVERSITY-OF-AGRICULTURAL-SCIENCES,-UPPSALA,-SWEDEN,-13-17-AUGUST-1990. Barrett,-P.R.F.;Greaves,-M.P.;Murphy,-K.J.;Pieterse,-A.H.;Wade,-P.M.;Wallsten,-M.-eds. WAGENINGEN-NETHERLANDS EUROPEAN-WEED-RESEARCH-SOCIETY 1990. pp. 243-248
LA: English
ER: F (Freshwater)
AB: Aquatic plants absorb P from the sediments as well as from the overlaying water. Leaves have a higher absorption capability of P than roots. Mature leaves of Potamogeton crispus  and Myriophyllum spicatum , are covered with thick mineral crusts which may comprise 80% of their dry weight. Such crusts may fix significant quantities of P. Leaf-crusts of P. crispus  contain calcite, quartz, apatite and aragonite. Aragonite is not always present in the crusts of Egeria densa . Roots of macrophytes absorb P from the soluble fraction of the sediment, at much higher rates than from the adsorbed or from the fixed fractions.
AN: 2922842

                                                                    819 of 1521  
TI: Phosphorus and nitrogen storage/release capacity of aquatic macrophytes in two wetland/stream systems of the Taylor Creek/Nubbins Slough and Kissimee River basin, Florida.
AU: Agami,-M.; Reddy,-K.R.; Graetz,-D.A.; Scinto,-L.J.
AF: Dep. Bot., Tel Aviv Univ., Tel Aviv 69978, Israel
CO: 8. Int. Symp. on Aquatic Weeds, Uppsala (Sweden), 13-17 Aug 1990
SO: 8th-INTERNATIONAL-SYMPOSIUM-ON-AQUATIC-WEEDS.-SWEDISH-UNIVERSITY-OF-AGRICULTURAL-SCIENCES,-UPPSALA,-SWEDEN,-13-17-AUGUST-1990. Barrett,-P.R.F.;Greaves,-M.P.;Murphy,-K.J.;Pieterse,-A.H.;Wade,-P.M.;Walsten,-M.-eds. WAGENINGEN-NETHERLANDS EUROPEAN-WEED-RESEARCH-SOCIETY 1990. pp. 1-2
LA: English
ER: F (Freshwater)
AB: The findings are presented of a field study conducted to determine the seasonality of nutrient uptake and storage, and the rate of plant tissue decomposition and subsequent nutrient release in aquatic plants in the Dry Lake 2 and Rucks Lake wetlands/stream systems in Florida, USA. Results suggest that the aquatic macrophytes present in both systems do not function as a net sink for P and N; these nutrients are stored transitionally and are eventually released back into the system.
AN: 2922086

                                                                    820 of 1521  
TI: Reactions depending on iron sulfide and linking geochemistry with biochemistry.
AU: Bloechl,-E.; Keller,-M.; Waechtershaeuser,-G.; Stetter,-K.O.
AF: Lehrst. Mikrobiol., Univ. Regensburg, Universitaetsstr. 31, D-8400 Regensburg, FRG
SO: PROC.-NATL.-ACAD.-SCI.-USA. 1992. vol. 89, no. 17, pp. 8117-8120
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Iron sulfide gives rise to unusual reducing reactions: some dependent on FeS/H sub(2)S synergism (NO sub(3)@)u-  arrow right  NH sub(3); HC  identical with  CH  arrow right  H sub(2)C = CH sub(2), H sub(3)C--CH sub(3); -CH sub(2)--CO-  arrow right  -CH = CH-, -CH sub(2)--CH sub(2)-; HS--CH sub(2)--COOH  arrow right  CH sub(3)--COOH; others dependent on FeS alone (HS--CH sub(2)--CH sub(2)--X  arrow right  CH sub(2) = CH sub(2) (where X = OH, SH, or NH sub(2))). The experimental conditions are geochemically plausible: 100 degree C, aqueous, nearly neutral, and fastidiously anaerobic. These reactions establish additional facts of soil chemistry, organic geochemistry, and the global nitrogen cycle, and point to the common evolutionary denominator of geochemistry and biochemistry. In their quest for phylogenetically deep-branching hyperthermophilic bacteria and archaea the authors tried to enrich organisms from sites with abundant pyrite deposits by using FeS/H sub(2)S as a hydrogen source. Surprisingly, in the presence of nitrate, large amounts of ammonia were formed abiotically within the noninoculated controls. Subsequent systematic experiments gave unequivocal evidence for a synergistic effect of H sub(2)S and FeS for the reduction of NO sub(3)@)u- to NH sub(3)-FeS alone causing only minor conversion, and H sub(2)S alone causing none. This kind of nitrate reduction may be assumed to proceed in nature. This result solves an old geochemical problem. The global nitrogen cycle can now be seen as operating partly by microbial nitrate reduction and partly by an FeS/H sub(2)S-driven abiotic nitrate reduction. The latter must have operated before the advent of nitrate-reducing microorganisms. This result is also of ecological significance. Nitrate ions and anaerobic pyrite-forming conditions cannot exist. This fact means that nitrate reduction, exhibited in the laboratory by anaerobic organisms from pyrite-forming habitats, may well be ecologically irrelevant. The result also has biochemical significance. It suggests a mechanistic commonality between the iron-sulfur clusters of nitrite reductases and nitrate reduction by FeS/H sub(2)S. The evolution of enzymatic nitrate reduction may now be traced back to abiotic nitrate reduction.
AN: 2919711

                                                                    821 of 1521  
TI: Nutrient release from sediments and the role of bioturbation in the Goro Lagoon (Italy).
AU: Barbanti,-A.; Ceccherelli,-V.U.; Frascari,-F.; Rosso,-G.; Reggiani,-G.
AF: Ist. Geol. Mar., CNR, Via Zamboni 65, Bologna, Italy
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 475-488
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: The nutrients released from the sea bottom through resuspension or diffusion may play an important role in determining the trophic state of aquatic environments. Direct measurements of NH sub(3), PO sub(4) and SiO sub(2) fluxes were made by means of benthic chambers in the Sacca di Goro, Italy, (a lagoon within the Po River Delta), as an obvious consequence of previous investigations into the processes of nutrient regeneration and release from the sea bottom in the coastal areas facing the Po River Delta. The role that macrobenthic organisms play through bioturbation and irrigation was investigated by determining and quantifying the species in the sediments below each benthic chamber. The results showed the following: generally high fluxes with significant differences between day and night hours; the importance of macrobenthos and the structures that it builds in sediments; limited differences between the two areas examined (North-Central area and Valle di Gorino--the eastern part of the Sacca di Goro Lagoon) which, however, differ considerably in terms of sedimentology and hydrology.
AN: 2919235

                                                                    822 of 1521  
TI: Relationships among Typha  biomass, pore water methane, and reflectance in a Delaware (U.S.A.) brackish marsh.
AU: Gross,-M.F.; Hardisky,-M.A.; Wolf,-P.L.; Klemas,-V.
AF: Dep. Biol., Georgian Court Coll., Lakewood, NJ 08701, USA
SO: J.-COAST.-RES. 1993. vol. 9, no. 2, pp. 339-355
LA: English
ER: B (Brackish)
AB: Methane is a "greenhouse effect" gas produced in wetland soils, yet factors controlling its production and emission are not well understood. Often, methane pore water concentration and atmospheric flux are positively correlated. If correlations can be found among wetland plant biomass, reflectance, and methane concentrations or flux, it may be possible to study the global methane cycle using remote sensing. Our study had two objectives: to determine if remote sensing could be used to estimate biomass of Typha angustifolia  plants in a Delaware (U.S.A.) brackish marsh, and to determine if Typha  plants influence dissolved pore water methane concentrations throughout a year. Canopy reflectance was correlated (r = 0.887) with live aerial biomass, which was correlated with live belowground biomass (r = 0.809). Dissolved pore water methane concentrations were generally lower in vegetated than in unvegetated areas. In vegetated areas only, concentrations were much lower in the top 10 cm of sediments than at greater depths. Since over 60% of the live root/rhizome biomass is in the top 10 cm, it is likely that an oxygenated rhizosphere and methane transport through roots kept the methane concentration low near the soil surface. Substantial growing season increases in methane at depths of 10-20 cm, where the remaining live tissue is, suggest the release of enough methanogenic substrates to cause methane production to exceed methane emission/oxidation. Overall, methane concentrations diminished in winter and increased in late spring, but lagged changes in soil temperature and in live aerial biomass by two months, and were not significantly correlated with substrate salinity. Since remote sensing can be used to estimate Typha  biomass, and since live root biomass influences the sedimentary methane reservoir, it might be possible to estimate methane concentrations indirectly based on remote sensing measurements.
AN: 2918983

                                                                    823 of 1521  
TI: Cycling of dissolved and particulate organic matter in the open ocean.
AU: Druffel,-E.R.M.; Williams,-P.M.; Bauer,-J.E.; Ertel,-J.R.
AF: Dep. Mar. Chem. and Geochem., Woods Hole Oceanogr. Inst., Woods Hole, MA, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C10, pp. 15,639-15,6
LA: English
ER: M (Marine)
AB: Radiocarbon ( Delta  super(14)C),  delta  super(13)C, bulk carbon and organic constituent concentration measurements are presented for dissolved and particulate carbon from the North Central Pacific Ocean (NCP) and the Sargasso Sea (SS). We operationally define three overlapping pools of dissolved organic carbon (DOC): (1) DOC that is oxidizable by UV radiation (DOC sub(uv)); (2) "extra" DOC measured by Co/CoO flow-through high-temperature catalytic oxidation (DOC sub(Ft-htc)), which also has low  Delta  super(14)C values like DOC sub(uv) (Bauer et al., 1992a); (3) a potential residual DOC fraction that is the difference between DOC measured by discrete-injection high-temperature catalytic oxidation (DOC sub(htc)) and DOC sub(Ft-htc), and which has unknown  Delta  super(14)C signature. The distribution of a large fraction of DOC appears to be controlled by circulation of deep ocean waters between major oceans. The DOC in the SS is slightly younger than would be expected if circulation was the sole process controlling DOC cycling. We propose that there is more bomb  super(14)C in the deep SS DOC to account for this difference. The  Delta  super(14)C values of suspended, and to a lesser extent sinking particulate organic carbon (POC), decrease with depth, with the suspended POC displaying a much steeper gradient in the SS than in the NCP. These data reflect the incorporation of low-activity organic matter into the POC pool, possibly through incorporation of DOC by physical adsorption and/or biological heterotrophy.
AN: 2918964

                                                                    824 of 1521  
TI: A dynamic nutrient budget of subsystem interactions in a salt marsh estuary.
AU: Childers,-D.L.; McKellar,-H.N.; Dame,-R.F.; Sklar,-F.H.; Blood,-E.R.
AF: Southeast Fish. Sci. Lab., NMFS, 9700 Ave. U, Galveston, TX 77551, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1993. vol. 36, no. 2, pp. 105-131
LA: English
ER: M (Marine); B (Brackish)
AB: In tidal salt marsh estuaries, the different habitats of the ecosystem interact primarily through the tidal creek water column. These interactions include nutrient and materials exchanges with the salt marsh, oyster reefs, creek bottoms, and adjacent uplands. Nutrient budgets are often used to synthesize these kinds of subsystem exchange data, and are usually based on annual totals without accounting for nutrient variability at finer temporal resolutions. In this paper, we present a dynamic budget of carbon (C), nitrogen (N), and phosphorus (P) for the North Inlet estuary, South Carolina that synthesizes subsystem flux data in a new way. We have developed a dynamic budget that uses a tidal hydrology model to generate daily areas of inundated intertidal habitat (i.e. vegetated marsh and oyster reef) from tidal heights calculated hourly and combines them with flux data to determine a net daily input to, or removal from, the water column. Daily surpluses or deficits of each nutrient were compared with daily rates of change in observed tidally-averaged nutrient concentrations. Particular emphasis was place on evaluating budget output from the intertidal subsystems. We compared our total annual budgets to values from syntheses of two North Inlet flux studies.
AN: 2918768

                                                                    825 of 1521  
TI: Northern Adriatic Sea: Oceanography of the basin proper and of the western coastal zone.
AU: Franco,-P.; Michelato,-A.
AF: Ist. Biol. Mare, CNR, Riva Sette Martiri 1364/A, 30122 Venezia, Italy
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 35-62
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: M (Marine)
AB: The oceanographic features of the Northern Adriatic Sea are reviewed with regard to the deeper basin proper and the shallow western coastal zone, and in relation to the interplay between the physical forcing and the distribution of chemical and biological properties in the basin. Some fundamental aspects are shown: the annual variation in the density structure of the water column, from the winter complete mixing to the strong stratification during the other seasons, and the related changes in the circulation pattern and in the dynamics of the horizontal and vertical transport processes; the role of the dynamic separation between the basin proper and the coastal zone due, with variable efficiency during the year, to the coastal frontal systems, and leading to different features in the waters separated by the fronts, in regard both to the physical and the biogeochemical processes. Some effects of the oceanographic structure of the basin on the cycling of nutrients and of the organogenic suspended matter, and on the appearance of dystrophic events are discussed.
AN: 2918765

                                                                    826 of 1521  
TI: Marine Coastal Eutrophication.
AU: Vollenweider,-R.A.; Marchetti,-R.; Viviani,-R.-(eds.)
CO: Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: SCI.-TOTAL-ENVIRON. 1992. no. suppl., (1315 pp)
LA: English
ER: M (Marine)
AB: There were more than 500 delegates and participants from 40 countries present at the International Conference on Marine Coastal Eutrophication: The Response of Marine Transitional Systems to Human Impact; Problems and Perspectives for Restoration, Bologna, Italy, 21 to 24 March, 1990, promoted by the Department of Environment of the Regional Government of Emilia-Romagna, and co-sponsored by the Italian National Research Council, UNEP, UNESCO, and FAO. Man-made eutrophication of the marine transitional systems located between land and the open oceans, i.e., estuaries, lagoons, bays, and coastal marine areas of various geomorphological configurations, also that of enclosed inland seas, has increased rapidly worldwide over the last decades affecting the marine processes that alter the natural dynamic equilibria and the biotic composition of the respective ecosystems. Consequently, eutrophication has become a treat to the sound functioning of these systems, impairing also their rational use as a resource for recreation, tourism, fishery and aquaculture. Some 98 papers were presented at the conference.
AN: 2918723

                                                                    827 of 1521  
TI: Effects of aeration and mixing on nitrogen and organic matter transformations in simulated fish ponds.
AU: Avnimelech,-Y.; Mozes,-N.; Weber,-B.
AF: Fac. Agricult. Eng., Technion Israel Inst. Technol., Haifa 32000, Israel
SO: AQUACULT.-ENG. 1992. vol. 11, no. 3, pp. 157-169
LA: English
ER: F (Freshwater)
AB: Both aeration and mixing are important design parameters in intensive aquaculture systems. The present study deals with the examination of the effect of each of these variables and their combined effect on the microbial transformations of organic carbon and of nitrogen. The most efficient organic carbon metabolism was found when both aeration and mixing were provided. Intensive organic matter degradation occurred also under strict anaerobic conditions, but not in systems with limited aeration. Aeration was essential for the existence of the nitrification process, however, the process was more efficient and started earlier when mixing was provided. Moreover, a denitrification process followed in aerated, non-mixed tanks, where an anaerobic bottom layer provided the conditions required for this process. Mixing of the water in fish ponds minimises the existence of non-desirable anaerobic zones in the pond and minimises ammonium accumulation in the water.
AN: 2918567

                                                                    828 of 1521  
TI: Posidonia oceanica : Uptake and mobilization of mercury in the Mediterranean basin.
AU: Maserti,-B.; Ferrara,-R.; Morelli,-M.
AF: CNR, Ist. Biofis., Via S. Lorenzo 26, 56127 Pisa, Italy
CO: FAO/UNEP/IAEA Consult. Meet. on the Accumulation and Transformation of Chemical Contaminants by Biotic and Abiotic Processes in the Marine Environment, La Spezia (Italy), 24-28 Sep 1990
SO: PROCEEDINGS-OF-THE-FAO-UNEP-IAEA-CONSULTATION-ON-THE-ACCUMULATION-AND-TRANSFORMATION-OF-CHEMICAL-CONTAMINANTS-BY-BIOTIC-AND-ABIOTIC-PROCESSES-IN-THE-MARINE-ENVIRONMENT-LA-SPEZIA,-ITALY,-24-28-SEPTEMBER-1990. Gabrielides,-G.P.-ed. International-Atomic-Energy-Agency,-Vienna-Austria;UNEP-Mediterranean-Action-Plan,-Athens-Greece;Minnesota-Univ.,-St.-Paul-USA.-Sea-Grant-Program ATHENS-GREECE UNEP 1991. no. 59 pp. 243-249
ST: MAP-TECH.-REP.-SER. no. 59
LA: English
ER: M (Marine)
AB: In studying the biogeochemical cycle of mercury in the Mediterranean basin the capability of the marine phanerogam Posidonia oceanica  and of its epiphytes to uptake and accumulate the metal was demonstrated. A Hg-roots/hg-sediment correlation was observed, which shows that the uptake of the metal occurs mainly through the root system, even if it is not possible to exclude that the metal can also be taken up from the water by the leaves. A Hg-epiphyte/Hg-leaf correlation was also observed probably due to a limited form of parasitism between the epiphytes and their substrate. Taking into account the high primary productivity (21 ton/ha/yr) and the large extension (50,000 sq. km) of Posidonia oceanica  prairies in the Mediterranean basin, the total mercury amount (9.5 ton/yr) mobilized from the sediment to the aquatic environment was evaluated.
AN: 2918241

                                                                    829 of 1521  
TI: Survival of pathogenic microorganisms in seawater.
AU: Romero,-P.; Borrego,-J.J.
AF: Dep. Microbiol., Univ. Malaga, Malaga, Spain
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-FINAL-REPORT-ON-PROJECTON-SURVIVAL-OF-PATHOGENIC-ORGANISMS-IN-SEAWATER. UNEP-Mediterranean-Action-Plan,-Athens-Greece;United-Nations-Environment-Programme,-Nairobi-Kenya ATHENS-GREECE UNEP 1991. no. 55 pp. 1-85
ST: MAP-TECH.-REP.-SER. no. 55
LA: English
ER: M (Marine)
AB: Microorganisms contained in sewage are dispersed by the turbulence diffusion where they are discharged into the sea. The adaptable capacity of a microbial cell may be overcome on its contact with the hostile environment, producing physiological damage which may sublethal or so intensive that it causes the death of the cell. This physiological damage or stress exerted by the marine environment on the allochtonous bacteria can be studied by observing either the bacterial structural disorganization or their inability to carry out a determined metabolic function when grown in a selective medium. However, these stressed cells can be developed in cultural media which do not contain inhibitory substances. The importance of the study of the physiological damage to pathogenic cells is based on the non-detection of these cells in the performance of standard microbiological tests, which are based on the examination of selective cultural media. A large variety of environmental conditions of factors exist which can kill, damage or simply cause the disappearance of microorganisms for the environment. These include physical, chemical and biological processes.
AN: 2918211

                                                                    830 of 1521  
TI: Chemical and biochemical dynamics of the C-layer.
OT: Khimicheskaya i biokhimicheskaya dinamika S-sloya
AU: Selin,-P.Yu.; Ajzatulin,-T.A.
SO: ECOLOGY-OF-THE-BLACK-SEA-COASTAL-ZONE..  EHKOLOGIYA-PRIBREZHNOJ-ZOMY-CHERNOGO-MORYA. Sapozhnikov,-V.V.-ed. MOSKVA-RUSSIA VNIRO 1992. pp. 100-126
ST: SB.-NAUCHN.-TR.-VNIRO.
LA: Russian
ER: M (Marine)
AB: The authors demonstrate the computation procedure of the chemical and biochemical dynamics of the hydrogen sulfide-oxygen coexistence layer (the C-layer) using field observation data from the northwestern Black Sea shelf and the Gotland Deep of the Baltic Sea. Data are presented on the vertical distribution profiles of vertical exchange coefficients, HS-oxidation rates, nitrification, denitrification, oxygen consumption, sulfate reduction rates, and duration of periodically occurring hydrogen sulfide zones. The appearance-disappearance of the hydrogen sulfide zones is shown to be largely dependent on the exchange conditions.
AN: 2917513

                                                                    831 of 1521  
TI: Microbiological activity in the water and bottom sediments of the Black Sea.
OT: Mikrobiologicheskaya aktivnost' v vode i donnykh osadkakh Chernogo morya
AU: Mitskevich,-I.N.; Kuzhinovskij,-V.A.; Rusanov,-I.I.
SO: ECOLOGY-OF-THE-BLACK-SEA-COASTAL-ZONE..  EHKOLOGIYA-PRIBREZHNOJ-ZOMY-CHERNOGO-MORYA. Sapozhnikov,-V.V.-ed. MOSKVA-RUSSIA VNIRO 1992. pp. 174-197
ST: SB.-NAUCHN.-TR.-VNIRO.
LA: Russian
ER: M (Marine)
AB: The paper presents data on the abundance of microorganisms, numbers of saprophytic forms, rates of  super(14)CO sub(2) dark fixation, heterotrophic potential and rates of sulfate reduction in the water and bottom sediments of the coastal Black Sea zone and at different depths in the central part of the sea. In many samples the dark CO sub(2) fixation values were found to be much higher than those obtained by earlier investigators. On the whole, the results suggest high rates of organic matter production and destruction processes in the Black Sea.
AN: 2917381

                                                                    832 of 1521  
TI: Study of the biogeochemical cycle of organophosphorus pesticides in Thermaikos Gulf, Greece.
AU: Fytianos,-K.; Samanidou,-V.
AF: Environ. Pollut. Contr. Lab., Univ. Thessaloniki, Greece
SO: FINAL-REPORTS-ON-RESEARCH-PROJECTS-DEALING-WITH-MERCURY,-TOXICITY-AND-ANALYTICAL-TECHNIQUES.  RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-TRAITANT-DU-MERCURE,-DE-LA-TOXICITE-ET-DES-TECHNIQUES-ANALYTIQUES. UNEP-Mediterranean-Action-Plan,-Athens-Greece;FAO,-Rome-Italy ATHENS-GREECE UNEP 1991. no. 51 pp. 133-140
ST: MAP-TECH.-REP.-SER. no. 51
LA: English
ER: M (Marine)
AB: Malathion and parathion are the most extensively used organophosphorus pesticides. Their application for the control of pests is clearly an important source of these chemicals in the environment. The object of this project was to investigate the seasonal variations and the distribution of the organophosphorus compounds in the Thermaikos Gulf (N. Greece). For the determination of these compounds, water and sediment samples were taken every three months from four sampling stations in the gulf, for a total period of one year. From the obtained data the conclusion is that the levels of the examined organophosphorus compounds are relatively close to those found for slightly polluted areas. However, particularly high concentrations were observed at the estuaries of Axios River and at the area where untreated municipal and industrial sewage are respectively discharged.
AN: 2917320

                                                                    833 of 1521  
TI: Biological activity of suspended matter and regeneration of biogenic elements in the Black Sea shelf zone.
OT: Biologicheskaya aktivnost' vzvesi i regeneratsiya biogennykh ehlementov v zone shel'fa Chernogo morya
AU: Agatova,-A.I.; Torgunova,-N.I.
SO: ECOLOGY-OF-THE-BLACK-SEA-COASTAL-ZONE..  EHKOLOGIYA-PRIBREZHNOJ-ZOMY-CHERNOGO-MORYA. Sapozhnikov,-V.V.-ed. MOSKVA-RUSSIA VNIRO 1992. pp. 275-305
ST: SB.-NAUCHN.-TR.-VNIRO.
LA: Russian
ER: M (Marine)
AB: The rates of organic matter transformation and nutrient regeneration in the zones of the Caucasian-Crimean and Bulgarian shelves are estimated based on the rates of the alkaline phosphatase-catalyzed phosphorolysis reaction, glycolytic hydrocarbon decomposition and the rates of complete organic matter oxidation to CO sub(2) and H sub(2)O catalyzed by enzymes of the electron transport system. The rates of organic matter destruction and nutrient regeneration were found to vary and to depend on the biological activity of suspended matter. The highest activity is characteristic for the eutrophic coastal waters (red tide) and the depth fall waters of the Bacis Black Sea Current. In these areas the time of nutrient recycling is at a minimum. Throughout the water column over the Bulgarian shelf the processes of ecosystem self-purification are less intensive than over the Caucasian shelf as the average time of complete organic matter oxidation there is twice longer.
AN: 2917270

                                                                    834 of 1521  
TI: (The importance of gelatinous macroplankton in the storage and transfer of metal pollutants (cadmium, copper, lead and zinc) in the northwestern Mediterranean.).
OT: Importance du macroplancton gelatineux dans le stockage et le transfert des metaux polluants (cadmium, cuivre, plomb et zinc) en Mediterranee nord-occidentale
AU: Romeo,-M.; Gnassia-Barelli,-M.; Carre,-C.
AF: INSERM Unite 303, "Mer et Sante", La Darse, 06230 Villefranche-sur-Mer, France
SO: FINAL-REPORTS-ON-RESEARCH-PROJECTS-DEALING-WITH-BIOACCUMULATION-AND-TOXICITY-OF-CHEMICAL-POLLUTANTS.  RAPPORTS-FINAUX-SUR-LES-PROJECTS-DE-RECHERCHE-TRAITANT-DE-LA-BIOACCUMULATION-ET-DE-LA-TOXICITE-DES-POLLUANTS-CHIMIQUES. UNEP-Mediterranean-Action-Plan,-Athens-Greece;FAO,-Rome-Italy ATHENS-GREECE UNEP 1991. no. 52 pp. 33-41
ST: MAP-TECH.-REP.-SER. no. 52
LA: French
ER: M (Marine)
AN: 2917059

                                                                    835 of 1521  
TI: Meridional fluxes of dissolved organic matter in the North Atlantic Ocean.
AU: Walsh,-J.J.; Carder,-K.L.; Mueller-Karger,-F.E.
AF: Dep. Mar. Sci., Univ. South Florida, St. Petersburg, FL 33701, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C10, pp. 15625-15637
LA: English
ER: M (Marine)
AB: Using bio-optical estimates of gelbstoff and a few platinum measurements of dissolved organic carbon (DOC sub(pt)), a budget of the meridional flux of DOC and dissolved organic nitrogen (DON) across 36 degree 25'N in the North Atlantic is constructed from previous inverse models of water and element transport. Distinct southward subsurface fluxes of dissolved organic matter (DOM) within subducted shelf water, cabelled slope water, and overturned basin water are inferred. Within two cases of a positive gradient of DOC sub(pt) between terrestrial/shelf and offshore stocks, the net equatorward exports of O sub(2) and DOC sub(pt) from the northern North Atlantic yield molar ratios of 2.1 to 9.1, compared to the expected Redfield O sub(2)/C ratio of 1.3. In the first case, 63% of the apparent oxygen utilization demands of the water column may be met by DOC, instead of only 14% in the second scenario, preserving a role for falling particles in the sea. With a DOC/DON ratio of 10, the larger net southward export of DON across 36 degree 25'N balances the postulated net northward input of 1.7 x 10 super(3) kg NO sub(3) s super(-1) of unutilized nitrate within the Gulf Stream. Without an enhanced supply of DOM from the shelves, a zero seaward gradient of DOM in the third case suggests that none of the poleward nitrate flux is returned southward as DON, but instead a net poleward flux of DON prevails as well. Our present estimates are confounded, however, by the seasonal and multiyear variability of sinking processes in the North Atlantic. Future active and passive remote sensors, field programs, and simulation models must now discriminate between particulate and dissolved components of surface color signals to verify the importance of both continental margins and DOM in global biogeochemical cycles.
AN: 2913762

                                                                    836 of 1521  
TI: The U.S.JGOFS Bermuda Atlantic time-series study: Towards an understanding of the temporal and spatial scales of ocean biogeochemistry.
AU: Michaels,-A.F.; Knap,-A.H.; Dacey,-J.W.H.
AF: Bermuda Biological Station for Research, Inc., 17 Biological Lane, Ferry Reach, GE01, Bermuda
CO: MTS '92: Global Ocean Partnership, Washington, DC (USA), 19-21 Oct 1992
SO: MTS-'-92:-GLOBAL-OCEAN-PARTNERSHIP.-PROCEEDINGS. Marine-Technology-Soc.,-Washington,-DC-USA WASHINGTON,-DC-USA MTS 1992. pp. 535-541
ST: PROC.-MAR.-TECHNOL.-SOC.-CONF.
LA: English
ER: M (Marine)
AB: Bermuda is the site of two long-term ocean time-series programs. At Hydrostation S, the ongoing biweekly profiles of temperature, salinity and oxygen now span 38 years. This is one of the longest open-ocean time-series datasets and provides a view of decadal scale variability in ocean processes. In 1988, the U.S.JGOFS Bermuda Atlantic Time-series Study began a wide range of measurements at a frequency of 14-18 cruises each year to understand temporal variability in ocean biogeochemistry. The adequate resolution of higher frequency temporal patterns and 3-D spatial processes will require the use of new sampling tools such as biogeochemical moorings and autonomous underwater vehicles. Plans exist to deploy both at the Bermuda site in the near future.
AN: 2913188

                                                                    837 of 1521  
TI: Molecular biology in studies of oceanic primary production.
AU: LaRoche,-J.; Falkowski,-P.G.; Geider,-R.
CA: Brookhaven Natl. Lab., Upton, NY (USA)
SO: 1992. 23 pp.
NT: NTIS Order No.: DE92016101/GAR.
RN: CONF-9204164-1 (CONF92041641)
LA: English
ER: M (Marine)
AB: Remote sensing and the use of moored in situ instrumentation has greatly improved our ability to measure phytoplankton chlorophyll and photosynthesis on global scales with high temporal resolution. However, the interpretation of these measurements and their significance with respect to the biogeochemical cycling of carbon relies on their relationship with physiological and biochemical processes in phytoplankton. For example, the use of satellite images of surface chlorophyll to estimate primary production is often based on the functional relationship between photosynthesis and irradiance. A variety of environmental factors such as light, temperature, nutrient availability affect the photosynthesis/irradiance (P vs I) relationship in phytoplankton. The authors present three examples showing how molecular biology can be used to provide basic insight into the factors controlling primary productivity at three different levels of complexity: 1. Studies of light intensity regulation in unicellular alga show how molecular biology can help understand the processing of environmental cues leading to the regulation of photosynthetic gene expression. 2. Probing of the photosynthetic apparatus using molecular techniques can be used to test existing mechanistic models derived from the interpretation of physiological and biophysical measurements. 3. Exploratory work on the expression of specific proteins during nutrient-limited growth of phytoplankton may lead to the identification and production of molecular probes for field studies.
AN: 2912700

                                                                    838 of 1521  
TI: Development of a dynamic model for the assessment of environmental radiation exposures through the stagnant water pathway.
OT: Erstellung eines dynamischen Modells zur Berechnung der Strahlenexposition ueber den Wasserpfad bei stehenden Gewaessern
AU: Saenger,-W.; Huebel,-K.
CA: Bundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (FRG)
SO: 1991. 48 pp
NT: NTIS Order No.: TIB/B92-02411/GAR.
RN: BMU-1991-320 (BMU1991320)
LA: German
ER: F (Freshwater)
AB: The model describes time-dependent changes in activity concentrations that 5 ecological variables (water, tripton, plankton, sediment, fishes) undergo in stagnant waters after brief exposure to high radioactive loads. The evaluation of Chernobyl data within the context of this model leads to meaningful results, if one describes the radionuclide migration as being faster than all subsequent activity changes - preferably as the so-called delta function. The model comprises a system of 5 coupled, analytically approachable rate balances in the form of 5 time-dependent first degree differential equations with constant coefficients. The latter are determined by adjusting the analytical solutions for the model system (model functions) to the values measured.
AN: 2912651

                                                                    839 of 1521  
TI: Potential role of sponge spicules in influencing the silicon biogeochemistry of Florida lakes.
AU: Conley,-D.J.; Schelske,-C.L.
AF: Horn Point Environ. Lab., Cent. Environ. and Estuar. Stud., Univ. Maryland, Box 775, Cambridge, MD 21613, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1993. vol. 50, no. 2, pp. 296-302
NT: Incl. bibliogr.: 38 ref.
LA: English
ER: F (Freshwater)
AB: Amorphous silica, e.g. biogenic silica (BSi), contained in diatoms and in sponge spicules was estimated by time course extraction from surficial sediment samples of 82 Florida, USA, lakes. Separation of diatom BSi from sponge BSi was based on the observation that diatoms completely dissolve within 2 h of digestion at 85 degree C in 1% Na sub(2)CO sub(3) whereas sponge spicules, which are generally larger than diatoms, take longer to dissolve. Because sponge spicules comprise a significant fraction of total amorphous silica extracted, we hypothesize that sponge spicules, which on average are larger than diatoms and require a longer time for complete dissolution, may constitute an important sink for BSi in Florida lakes.
AN: 2907154

                                                                    840 of 1521  
TI: Earth Observation System (EOS): Ecological priorities and observation planning: 1 - Priorities.
AU: Kondrat'-ev,-K.Ya.
AF: Ecol. Security Cent., Russian Acad. Sci., St. Petersburg, Russia
SO: SOV.-J.-REMOTE-SENS. 1993. vol. 10, no. 3, pp. 519-544
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The paper describes the scientific priorities which form the basis for the development of the American global ecological monitoring system (EOS). Key value is placed on studies of energy and water cycles and the biogeochemical cycles of carbon, nitrogen and sulphur together with the implementation of an ecosystem approach to observation planning. Global monitoring of bioproductivity on land and in the Pacific Ocean (the dynamics of forests, phytoplankton, etc.) is amongst the primary problems. Polar regions require particular attention (essentially in the context of the effect of the dynamics of the cryosphere on the climate). Corresponding requirements on the observational data are discussed in detail.
AN: 2906596

                                                                    841 of 1521  
TI: Biological nitrogen fixation (acetylene reduction) associated with decomposing Avicennia marina  leaves in the Beachwood Mangrove Nature Reserve.
AU: Mann,-F.D.; Steinke,-T.D.
AF: Estuar. and Mar. Group, Dep. Bot., Univ. Durban-Westville, Priv. Bag X54001, Durban 4000, South Africa
SO: S.-AFR.-J.-BOT.-S.-AFR.-TYDSKR.-PLANTKD. 1992. vol. 58, no. 6, pp. 533-536
LA: English
AB: Nitrogen fixation of decomposing Avicennia marina  (Forssk.) Vierh. leaves was studied over a period of 16 weeks under exposed and submerged conditions. Rates of acetylene reduction activity (ARA) were highest under exposed conditions and reached a maximum after three to four weeks. Percentage total nitrogen increased during decomposition, the increase being greatest under submerged conditions, but this was not directly related to nitrogen fixation. Bacteria were considered to be the main agents of nitrogen fixation. Rates of decomposition were highest under exposed conditions. The contribution of nitrogen fixation to the nitrogen budget is significant.
AN: 2905618

                                                                    842 of 1521  
TI: Distribution of organic carbon in sediments from the Arabian Sea.
AU: Paropkari,-A.L.; Mascarenhas,-A.; Prakashbabu,-C.
CA: National Inst. of Oceanography, Dona Paula (India)
SO: TECH.-REP.-NATL.-INST.-OCEANOGR.-INDIA. 1991. no. 18, 46 pp
RN: NIO/TR-18/91 (NIOTR1891)
LA: English
ER: M (Marine)
AB: Many earlier studies on the distribution of organic carbon in the Arabian Sea sediments have projected contradictory opinions on the factors favouring accumulation and preservation of organic carbon by these sediments. An attempt is made to reevaluate the role of various sedimentary parameters on the surface distribution of organic carbon in the Arabian Sea. The revaluation identifies 2 regional bands of organic-rich sediments -- one along the slope of the Arabian Peninsula and the other along the western slope of India. The organic carbon distribution mirrors the surface productivity -- high in the peripheral portions and low in the open ocean, suggesting that it derives mainly from marine origin. A perfect coincidence of organic enrichment on the slopes with the oxygen minimum zone (150-150 m) clearly demonstrates the influence of anoxic waters on organic enrichment. Bottom water anoxia (though a principal factor for organic enrichment on the slopes) and its interplay with other depositional parameters cumulatively determines the "degree of preservation" and fixes the location of organic enrichment along the slopes.
AN: 2905562

                                                                    843 of 1521  
TI: Initial burial and subsequent degradation of sedimented phytoplankton: Relative impact of macro- and meiobenthos.
AU: Webb,-D.G.; Montagna,-P.A.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1993. vol. 166, no. 2, pp. 151-163
LA: English
ER: M (Marine)
AB: The initial burial (transfer through the sediment-water interface) and subsequent degradation of sedimented phytoplankton was examined in the laboratory in sediments containing meiofauna, both with and without macrofauna, over a 10-day period. Burial and degradation were monitored by following changes in vertical profiles of Chl a and phaeopigments in sediment columns with and without an addition of senescent Skeletonema costatum  Greville (Cleve) cells to the sediment surface. The macrofauna present in the cores consisted of a subsurface deposit-feeder assemblage typical of organically enriched habitats. Upon diatom addition, the visual redox potential discontinuity (RPD) rose to or near the sediment surface. Chl a and phaeopigment levels increased 6 and 3 days after diatom addition, respectively, with no difference in concentrations in the presence or absence of macrofauna. These increases appeared to be confined to the top 5 mm of sediment. Overall, phaeopigment concentrations were higher in cores containing macrofauna. A minimum of 83% of the added Chl a was transferred through the sediment-water interface in 10 days. In organically enriched habitats, the initial burial and subsequent degradation of sedimented phytoplankton appears to be a process dominated by the meiofaunal and microbial communities, and unaffected by subsurface deposit-feeding macrofauna.
AN: 2902683

                                                                    844 of 1521  
TI: The role of planktonic algae in the cycling of Zn and Cu in a productive soft-water lake.
AU: Reynolds,-G.L.; Hamilton-Taylor,-J.
AF: Inst. Environ. and Biol. Sci., Univ. Lancaster, Lancaster, LA1 4YQ, UK
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 8, pp. 1759-1769
LA: English
ER: F (Freshwater)
AB: Concentrations of dissolved Zn and Cu were measured alongside biomass (algal numbers, organic C, and Chl a) and dissolved micronutrients (P, Si) over an 8-week period, covering a pronounced bloom of the diatom, Asterionella . The distribution of dissolved Zn appears to be affected by algal cycling in two ways: in the period up to and including the diatom maximum, dissolved Zn correlates (P < 0.01) positively with phosphate and silicate, indicating atomic C:P:Zn ratios of 106:1:0.034, and negatively with Chl a; and following stratification, epilimnetic concentrations are significantly (P < 0.01) less than those in the hypolimnion. Dissolved Cu distributions are unaffected by the spring diatom bloom. The Zn and Cu contents of the diatom standing crop were also determined by elemental analysis of suspended particulate material in two consecutive years, providing independent estimate of metal stoichiometry. Mass budgets indicate a substantial removal and transfer to the sediments of Zn via phytoplankton, but a negligible effect on the cycling of Cu.
AN: 2902540

                                                                    845 of 1521  
TI: External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay.
AU: Magnien,-R.E.; Summers,-R.M.; Sellner,-K.G.
AF: Maryland Dep. Environ., Chesapeake Bay and Watershed Manage. Adm., 2500 Broening Highway, Baltimore, MD 21224, USA
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 497-516
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: External nutrient loadings, internal nutrient pools, and phytoplankton production were examined for three major subsystems of the Chesapeake Bay Estuary - the upper Mainstem, the Patuxent Estuary, and the Potomac Estuary - during 1985-1989. The atomic nitrogen to phosphorus ratios (TN:TP) of total loads to the Mainstem, Patuxent, and the Potomac were 51, 29 and 35, respectively. Most of these loads entered at the head of the estuaries from riverine sources and major wastewater treatment plants. Approximately 7-16% of the nitrogen load entered the head of each estuary as particulate matter in contrast to 48-69% for phosphorus. This difference is hypothesized to favor a greater loss of phosphorus than nitrogen through sedimentation and burial. This process could be important in driving estuarine nitrogen to phosphorus ratios above those of inputs. Water column TN:TP ratios in the tidal fresh, oligohaline, and mesohaline salinity zones of each estuary ranged from 56 to 82 in the Mainstem, 27 to 48 in the Patuxent, and 72 to 126 in the Potomac. A major storm event in the Potomac watershed was shown to greatly increase the particulate fraction of nitrogen and phosphorus and lower the TN:TP in the river-borne loads. The load during the month that contained this storm (November 1985) accounted for 11% of the nitrogen and 31% of the phosphorus that was delivered to the estuary by the Potomac River during the entire 60-month period examined here.
AN: 2902424

                                                                    846 of 1521  
TI: Nutrient flux in a landscape: Effects of coastal land use and terrestrial community mosaic on nutrient transport to coastal waters.
AU: Correll,-D.L.; Jordan,-T.E.; Weller,-D.E.
AF: Smithson. Environ. Res. Cent., P.O. Box 28, Edgewater, MD 21037, USA
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 431-442
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Long-term interdisciplinary studies of the Rhode River estuary and its watershed in the Mid-Atlantic Coastal Plain of North America have measured fluxes of nitrogen and phosphorus fractions through the hydrologically-linked ecosystems of this landscape. These ecosystems are upland forest, cropland, and pasture; streamside riparian forests; floodplain swamps; tidal brackish marshes and mudflats; and an estuarine embayment. Croplands discharged far more nitrogen per hectare in runoff than did forests and pastures. However, riparian deciduous hardwood forest bordering the cropland removed over 80 percent of the nitrate and total phosphorus in overland flows and about 85 percent of the nitrate in shallow groundwater drainage from cropland. Nevertheless, nutrient discharges from riparian forests downslope from croplands still exceeded discharges from pastures and other forests. The atomic ratio of nitrogen to phosphorus discharged from the watersheds into the estuary was about 9 for total nutrients and 6 for inorganic nutrient fractions. Such a low N:P ratio would promote nitrogen rather than phosphorus limitation of phytoplankton growth in the estuary. Estuarine tidal marshes trapped particulate nutrients and released dissolved nutrients. Subtidal mudflats in the upper estuary trapped particulate P, released dissolved phosphate, and consumed nitrate. This resulted in a decrease in the ratio of dissolved inorganic N:P in the estuary. However, the upper estuary was a major sink for total phosphorus due to sediment accretion in the subtidal area. The nitrogen and phosphorus discharges into the Rhode River, although a small fraction of total loadings to the watershed, were large enough to cause seriously overenriched conditions in the upper estuary.
AN: 2902313

                                                                    847 of 1521  
TI: A comparison of ecosystem dynamics in freshwater wetlands.
AU: Hopkinson,-C.S.,Jr.
AF: Ecosyst. Cent., Mar. Biol. Lab., Woods Hole, MA 02543, USA
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 549-562
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
ER: F (Freshwater)
AB: The effects of system closure on the dynamics of productivity and nutrient cycling are examined in four wetlands that differ in plant growth form and magnitudes and sources of water input and nutrient loading. Dynamics in relatively closed ombrotrophic Carex  marsh and Taxodium  swamp systems from Okefenokee Swamp are compared to those in open, rheotrophic riparian systems. The riparian systems examined include Zizaniopsis  marshes along the tidal freshwater portion of the Altamaha River in Georgia and a mature Taxodium-Nyssa  swamp along the Cache River in Illinois. Water budgets in the ombrotrophic systems are dominated by precipitation inputs while in the riparian wetlands they are dominated by overbank flooding. Nutrient loading to the open and closed systems differs by only two orders of magnitude, the former depending on atmospheric inputs and the latter depending on tidal and riverine inputs. Comparisons of nutrient import, export, and retention indicate that greater than 90% of inorganic nutrients are retained in the closed systems while less than 5% are retained in the open systems. Nutrient budgets for wetland vegetation, including aboveground uptake, root uptake, leaching, death, and translocation, are constructed. Strong differences in nutrient conservation within plant communities are found between marsh and forested closed systems and between open and closed systems as a whole. There is the indication that nutrients turn over more rapidly and nutrient cycles are less retentive and conservative as systems become more open and nutrient inputs increase.
AN: 2902170

                                                                    848 of 1521  
TI: Loss of nutrients from catchments and their ecological impacts in the Peel-Harvey estuarine system, Western Australia.
AU: McComb,-A.J.; Humphries,-R.
AF: Environ. Sci., Murdoch Univ., Murdoch, W.A. 6009, Australia
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 529-537
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
AB: Rivers draining coastal-plain soils with a low phosphorus-binding capacity load nutrients into the estuarine system in winter. Phosphorus is largely by diatom blooms and recycled via the sediments to support growth, during the warmer months, of blue-green algae in Harvey Estuary or macroalgae in Peel Inlet. The magnitude of blue-green algae (Nodularia ) blooms is related to the amount of river water entering in winter; blooms collapse as salinities rise toward that of the ocean. For macroalgae the relationship between light and nutrient availability is of critical importance. Control measures are concerned with reducing phosphorus loads from catchments and increasing water exchange with the ocean through the proposed construction of a new channel.
AN: 2902127

                                                                    849 of 1521  
TI: The role of humic substances in the mobilization of mercury from watersheds.
AU: Mierle,-G.; Ingram,-R.
AF: Ontario Minist. Environ., Dorset Res. Cent., P.O. Box 39, Dorset, ON P0A 1EO, Canada
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 349-357
LA: English
ER: F (Freshwater)
AB: The total Hg concentration was estimated in eight inflowing streams from two headwater lakes and catchments in Ontario over a 2-yr period. Marked seasonal patterns in all brown water streams were evident, with highest levels usually occurring in the early fall and early spring. The seasonal pattern and the estimated export of Hg was most closely related to color, a measure of humic matter in the water. The data suggest that humic matter controls the solubility and watershed export of Hg deposited in precipitation.
AN: 2901008

                                                                    850 of 1521  
TI: The coupling of mercury and organic matter in the biogeochemical cycle--towards a mechanistic model for the boreal forest zone.
AU: Meili,-M.
AF: Inst. Limnol., Uppsala Univ., Box 557, 75122 Uppsala, Sweden
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 333-347
LA: English
ER: F (Freshwater)
AB: In boreal forest lakes, high Hg concentrations in fish are common, even in remote areas. In this paper, the effects of atmospheric Hg pollution in Sweden are synthesized and related to a concept based on the strong interaction of Hg with biogenic matter (Hg/B). Based on this concept, a compartment model is developed to predict concentrations, pool sizes, flux rates and turnover times of Hg along the biogeochemical cycle, including atmosphere, forest soils, surface runoff, lake waters, and aquatic biota. The aim is to provide a conceptual framework, both for a comprehensive mechanistic model, and for predictions from readily available information, such as regional data on acid deposition, air temperature and surface runoff, and local data on the trophic status of lakes with respect to humus and nutrient concentrations. It suggests a strong influence of climate on the susceptibility of soil and lake ecosystems in the boreal region to Hg contamination.
AN: 2900982

                                                                    851 of 1521  
TI: Laboratory production of bromoform, methylene bromide, and methyl iodide by macroalgae and distribution in nearshore southern California waters.
AU: Manley,-S.L.; Goodwin,-K.; North,-W.J.
AF: Dep. Biol., California State Univ., Long Beach, CA 90840, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 8, pp. 1652-1650
LA: English
ER: M (Marine)
AB: Production rates of bromoform (CHBr sub(3)), methylene bromide (CH sub(2)Br sub(2)), and methyl iodide (CH sub(3)I) were measured in the laboratory for 11 species of marine macroalgae. Production rates of the volatile bromomethanes extrapolated to a global scale suggest that marine macroalgae produce 2 x 10 super(11) g Br/yr, 98% of which is bromoform. Laminarians (kelps) produce 61% of this organic Br. These calculations suggest that marine macroalgae are important in the biogeochemical cycling of Br. Seawater concentrations of CHBr sub(3), CH sub(2)Br sub(2), and CH sub(3)I were determined from various southern California coastal locales. High concentrations were measured in seawater from the canopy and the bottom of a dense bed of Macrocystis) as compared to other sites. Surface seawater concentrations of these halomethanes showed a strong cross-shore gradient with the highest concentration in the kelp canopy and the lowest at 5 km offshore. Seawater adjacent to decaying macroalgae on the bottom of a submarine canyon was not enriched in halomethanes relative to surface water. Water exiting a productive estuary was enriched only with CH sub(2)Br sub(2), although two algal species that are abundant there (Ulva) and Enteromorpha ) showed high laboratory production rates of both CHBr sub(3) and CH sub(2)Br sub(2).
AN: 2899845

                                                                    852 of 1521  
TI: Specific rates of net methylmercury production in lake sediments.
AU: Matilainen,-T.; Verta,-M.; Niemi,-M.; Uusi-Rauva,-A.
AF: Dep. Limnol., Univ. Helsinki, Viikki, E-house, SF-00710 Helsinki, Finland
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 595-605
LA: English
ER: F (Freshwater)
AB: Specific rates of Hg ( super(203)HgCl sub(2)) methylation and MeHg ( super(14)CH sub(3)HgI) demethylation in aerobic and anaerobic conditions were determined in samples of surface sediments (0 to 2 cm) taken from five small headwater lakes in Southern Finland. The highest rates of methylation were measured in anaerobic conditions. however, the importance of aerobic methylation increased with increasing Fe and Mn content in sediment. There was little difference between aerobic and anaerobic demethylation. The results demonstrate that the net MeHg production in lake sediments depends on the individual characteristics of the lake, particularly pH and sediment properties. These characteristics seem to affect demethylation in anaerobic conditions and methylation in aerobic conditions.
AN: 2897894

                                                                    853 of 1521  
TI: Mercury cycling in a northern Wisconsin seepage lake: The role of particulate matter in vertical transport.
AU: Hurley,-J.P.; Watras,-C.J.; Bloom,-N.S.
AF: Bur. Res., Wisconsin Dep. Natural Resour., 3911 Fish Hatchery Rd., Fitchburg, WI 53711, USA
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 543-551
LA: English
ER: F (Freshwater)
AB: During summer stratification, total mercury (Hg sub(T)) reached maximum concentrations in the O sub(2)-depleted, hypolimnion of Little Rock Lake, WI. Initially, the hypolimnetic increase was attributed solely to redox-controlled release of Hg from bottom sediments. However, subsequent depth profiles of Hg indicated that hypolimnetic Hg enrichment could also result from the downward transport and recycling of particulate Hg prior to incorporation in the sediments. Contrasts between Fe and Hg cycles in this lake reinforce this notion. Increases in hypolimnetic Fe were observed during both summer and winter O sub(2) decreases. In contrast, hypolimnetic Hg concentrations declined during winter. In the ice-free season, the distribution of particulate mercury (Hg sub(P)) correlated with the distribution of chlorophyllous particulates in this lake, re-emphasizing the importance of biotic processes in controlling Hg cycling in the hypolimnion.
AN: 2897861

                                                                    854 of 1521  
TI: Sources, cycling and fate of contaminants in Chesapeake Bay.
AU: Sanders,-J.G.; Riedel,-G.F.
AF: Acad. Nat. Sci., Benedict Estuarine Res. Lab., Benedict, MD 20612, USA
CO: 16. Bienn. Conf. of the Int. Assoc. on Water Pollution Research and Control, Washington, DC (USA), 24-30 May 1992
SO: WATER-QUALITY-INTERNATIONAL-'-92-WASHINGTON-DC,-1992. Suzuki,-M.;et-al.-eds.. 1992. vol. 26, no. 1-12 pp. 2645-2652
ST: WATER-SCI.-TECHNOL. vol. 26, no. 1-12
NT: Part 6.
LA: English
ER: B (Brackish)
AB: In order to predict and control the impacts of contaminants to coastal ecosystems like the Chesapeake Bay, we must first understand the geochemical, physical, and biological factors that control contaminant transport, transformation, uptake, and fate. Some processes exert control over broad groups of contaminants; the importance of others varies with specific contaminants. Many of these processes are well known and are amenable to predictive modeling, while others are less well understood and require further attention and research. Most important for the future protection of the Chesapeake Bay, and other coastal ecosystems, will be a coordinated approach (both in the research that must be conducted and in the management decision that must be made), linking scientists of many disciplines with those changed with ecosystem protection.
AN: 2896945

                                                                    855 of 1521  
TI: Modelling the Phanerozoic carbon cycle and climate: Constraints from the  super(87)SR/ super(86)SR isotopic ratio of seawater.
AU: Francois,-L.M.; Walker,-J.C.G.
AF: Space Phys. Res. Lab., Dep. Atmos., Oceanic, and Space Sci., Dep. Geol. Sci., Univ. Michigan, Ann Arbor, MI 48109, USA
SO: AM.-J.-SCI. 1992. vol. 292, no. 2, pp. 81-135
LA: English
ER: M (Marine)
AB: A numerical model describing the coupled evolution of the biogeochemical cycles of carbon, sulfur, calcium, magnesium, phosphorus, and strontium has been developed to describe the longterm changes of atmospheric carbon dioxide and climate during the Phanerozoic. The emphasis is on the effects of coupling the cycles of carbon and strontium. Various interpretations of the observed Phanerozoic history of the seawater  super(87)Sr/ super(86)Sr ratio are investigated with the model. More specifically, the abilities of continental weathering, volcanism, and surface lithology in generating that signal are tested and compared. It is suggested that the observed fluctuations are mostly due to a changing weatherability over time. It is shown that such a conclusion is very important for the modelling of the carbon cycle.
AN: 2895461

                                                                    856 of 1521  
TI: Rates of amino acid uptake and mineralization in Resurrection Bay (Alaska) sediments.
AU: Sugai,-S.F.; Henrichs,-S.M.
AF: Inst. Mar. Sci., Sch. Fish. and Ocean Sci., Univ. Alaska, Fairbanks, AK 99775-1080, USA
SO: MAR.-ECOL.-PROG.-SER. 1992. vol. 88, no. 2-3, pp. 129-141
NT: Bibliogr.: 25 ref.
LA: English
ER: M (Marine)
AB: The rates of uptake and mineralization of glutamic acid, alanine, lysine, serine and glycine were measured in sediments from Resurrection Bay, Alaska, USA, using  super(14)C-labeled amino acids. Amino acid concentrations and specific activities were determined by high performance liquid chromatography. The fate of radiolabeled amino acids added to killed control sediments was also investigated. Free amino acids were lost from the dissolved pool by both bacterial uptake and adsorption to sediment particles. Adsorption was the dominant process for the basic amino acid lysine and was responsible for about half of the glutamic acid and alanine removal from solution. Rates of bacterial mineralization of porewater amino acids, calculated using a model which corrects for the effects of adsorption, were 8 (glutamic acid), 1 (alanine), 0.7 (lysine), 1 (serine) and 3 (glycine) nmol/cm super(3) sediment/d.
AN: 2892154

                                                                    857 of 1521  
TI: Decomposition and release of elements from zooplankton debris.
AU: Lee,-B.-G.; Fisher,-N.S.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: MAR.-ECOL.-PROG.-SER. 1992. vol. 88, no. 2-3, pp. 117-128
NT: Bibliogr.: 55 ref.
LA: English
ER: M (Marine)
AB: In experiments examining the retention of trace elements in decomposing zooplankton debris, the rates of C degradation and metal release from radiolabeled copepod fecal pellets and carcasses were measured for up to 1 mo using radiotracers. Fecal pellets incubated at 18 and 2 degree C retained 35 to 40% and 80% of their  super(14)C, respectively, after 30 d. Carcasses retained only 13 to 18% and 28 to 38% of their  super(14)C after 18 d and 18 and 2 degree C, respectively. Leaching of  super(14)C from fecal pellets and carcasses as DO super(14)C accounted for about half of the  super(14)C loss, even in the absence of microbial activity. Proportionately more of the  super(14)C from carcasses was microbially oxidized to  super(14)CO sub(2) than  super(14)C from fecal pellets. Release of the particle-reactive transuranic element  super(241)Am from fecal pellets was unaffected by microbial activity while release of  super(75)Se and  super(65)Zn from both fecal pellets and carcasses increased with microbial activity and closely followed  super(14)C loss. Release rates of all elements decreased exponentially over time, with the most pronounced decreases occurring within the first 6 d. Retention half-times (t sub(r is equivalent )'s) of  super(241)Am were  greater than or equal to 48 d in fecal pellets. By contrast, the t sub(r is equivalent )'s for  super(65)Zn ranged from 2.1 to 13.5 d in fecal pellets and both  super(65)Zn and  super(75)Se had t sub(r is equivalent )'s of only about 1 d in carcasses.
AN: 2892122

                                                                    858 of 1521  
TI: Calcite precipitation and solution in Lake Laacher See.
AU: Friebertshaeuser,-D.; Moegling,-A.; Bahring,-B.
SO: LIMNOLOGY-OF-EIFEL-MAAR-LAKES. Scharf,-B.W.;Bjoerk,-S.-eds. STUTTGART-FRG SCHWEIZERBART'-SCHE-VERLAGSBUCHHANDLUNG 1992. no. 38 pp. 85-102
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 38
LA: English
ER: F (Freshwater)
AB: The annual development of carbonate precipitation and solution in the volcanic crater-lake Laacher See was studied by investigations of water chemistry, sediments collected in sediment traps, and the application of a thermodynamic model. The chemical data show a clear relation between calcite saturation and water temperature. During the summer temperature maximum a supersaturation of up to 10-fold develops as a result of CO sub(2)- diffusion and decreased calcite solubility. The precipitation of calcite is triggered by the growth of diatoms of the genera Cyclotella) and Synedra  in spring and early summer. During the precipitation period (April-July) the diminution of the planktonic diatoms is balanced by a rising supersaturation. The preservation of the calcite crystals is strongly coupled to the saturation in the water column. The morphology and surface of the calcite crystals proves a partial solution of calcite in the undersaturated, deeper water. These effects explain the depth dependent zonation of the bottom sediments that were found in earlier investigations.
AN: 2891245

                                                                    859 of 1521  
TI: (Proteins, carbohydrates, and chlorophyll a of the particulate organic matter in three different oceanic environments: Sea of Portugal, California Gulf and NW Baja California Sur.).
OT: Proteinas, carbohidratos y clorofila a de la materia organica particulada, en tres diferentes ambientes oceanicos: Mar de Portugal, Golfo de California y NW de Baja California Sur
AU: Lechuga-Deveze,-C.H.; Ayala-Rocha,-B.; Garate-Lizarraga,-I.
AF: Cent. Invest. Biol. Baja California Sur, Apdo. Postal 128, 23000 La Paz, B.C.S., Mexico
SO: AN.-INST.-CIENC.-MAR-LIMNOL.-UNIV.-NAC.-AUTON.-MEX. 1989. vol. 16, no. 1, pp. 147-156
LA: Spanish
ER: M (Marine)
AB: A survey on the protein and carbohydrate content of the particulate organic matter in 3 different oceanic environments: the Atlantic Ocean off Portugal, the California Gulf and the Pacific Ocean off Baja California was conducted. The protein concentration of the detrital particulate matter was quite constant for the 3 areas (31.9 mg prot/m super(3)); the carbohydrate concentrations ranged between 5.4 and 117 mg carbohydrate/m super(3). It is presumed that proteins and carbohydrates of the bacteria/detritus fraction might be an important energy source for other members of the food chain, and this energy input is being modified by variations in the source and concentration of particulate carbohydrates.
AN: 2889081

                                                                    860 of 1521  
TI: Behavior and dynamic balance of manganese during spring bloom in Funka Bay, Japan.
AU: Kudo,-I.; Ohyama,-T.; Nakabayashi,-S.; Kuma,-K.; Matsunaga,-K.
AF: Dep. Chem., Fac. Fish., Hokkaido Univ., Hakodate 041, Japan
SO: MAR.-CHEM. 1992. vol. 40, no. 3-4, pp. 273-289
LA: English
ER: M (Marine)
AB: The distribution of manganese was investigated during a spring bloom in Funka Bay by chemically segregating dissolved, soluble and refractory Mn. The concentration of dissolved Mn changed slightly owing to assimilation by phytoplankton and dissolution of aerosol particles. A simple mass balance was adopted in this bloom period to clarify the dynamics of Mn in the euphotic zone. From this result, the assimilated Mn was estimated to be 10.6  mu mol/m super(2)/day. However, it was observed that the total Mn increased significantly despite the removal of Mn by settling. This Mn increase was attributable to atmospheric transport of fine particles from land close to this bay.
AN: 2884760

                                                                    861 of 1521  
TI: Seasonal iron cycling in the salt-marsh sedimentary environment: The importance of ligand complexes with Fe(II) and Fe(III) in the dissolution of Fe(III) minerals and pyrite, respectively.
AU: Luther,-G.W.,III; Kostka,-J.E.; Church,-T.M.; Sulzberger,-B.; Stumm,-W.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: MAR.-CHEM. Millero,-F.J.-ed. 1992. vol. 40, no. 1-2, pp. 81-103
NT: Spec. Iss.: Progress in Mar. Chem.
LA: English
ER: M (Marine)
AB: A biogeochemical cycle is proposed for the reactivity of iron in salt-marsh sediments. The main reactions of the iron cycle are: (1) solubilization of Fe(III) by organic ligands; (2) reduction of soluble Fe(III) to Fe(II) by these ligands, soluble reduced sulfur or solid phase reduced sulfur; (3) the oxidation of the resulting Fe(II) (complexed to organic chelates) by Fe(III) minerals; (4) the formation of iron sulfide minerals when dissolved sulfide is in excess. The cycle of iron solubilization will continue as long as bacteria and/or plants produce organic ligands. The cycle will stop when sulfate reduction rates are high and organic ligand production is low. At this point soluble hydrogen sulfide reacts with Fe(II) and Fe(III) to form sulfide minerals. Penetration of O sub(2) into the surface sediments will also oxidize Fe(II) to Fe(III) with subsequent formation of Fe(III) (oxy)hydroxide minerals. The reactions which represent the iron cycle indicate that the iron mineral system has substantial acid/base buffering capacity.
AN: 2884617

                                                                    862 of 1521  
TI: Sampling and experimental challenges for the next decade in marine organic chemistry - a prospectus.
AU: Wakeham,-S.G.
AF: Skidaway Inst. Oceanogr., P.O. Box 13687, Savannah, GA 31416, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 239-242
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Major advances in marine organic chemistry during the past decade have come on three fronts. The application of modern analytical tools has made possible measurements of many more and more complex organic compounds in seawater and sediments than was previously possible. New sampling techniques have provided new and important sample types for analysis of their organic composition. Manipulative experiments to study processes are becoming common. In order to keep progressing into the future, however, several areas must see continued advancement. Fundamental steps must be taken to better sample and characterize the large pool of dissolved and colloidal organic material. Improved in situ sensing systems for continuous and real-time measurements of dissolved components would greatly help in this characterization. Increased use of time-series sediment traps for organic geochemical investigations is needed to enhance our understanding of temporal variations in organic compound flux and cycling. Increased emphasis on in situ experimentation will be needed in order to understand mechanisms and rates for biogeochemical processes in which organic matter participates.
AN: 2883988

                                                                    863 of 1521  
TI: Importance of isotope measurements in marine organic geochemistry.
AU: Druffel,-E.R.M.; Williams,-P.M.
AF: Chem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 209-215
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: We present here some specific areas of research, prefaced by brief and selected reviews, that address the cycling of organic matter in the marine environment. These are areas in which isotopic signatures will provide vital answers or clues.
AN: 2883963

                                                                    864 of 1521  
TI: Organic matter in the water column: Future research challenges.
AU: Lee,-C.; Wakeham,-S.G.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 95-118
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Recent research has greatly changed our knowledge of processes affecting organic matter in the water column. Here we review some of this recent research and suggest several areas which are particularly challenging for future studies. Major areas discussed are newly developed methods of dissolved organic carbon (DOC) analysis and the implications of the results, and the potential significance of organic colloids in seawater. Recent advances in techniques for the analysis of small, labile organic molecules and in radiotracer techniques used to follow rates and mechanisms of biological consumption are also discussed. Ocean-atmosphere transport and photochemical processes can act as both sources and sinks of organic matter in the sea. This is an area where significant progress has been made recently. Finally, we discuss current knowledge of river transport to the oceans and particle sedimentation in the sea as well as some of the limitations on this knowledge.
AN: 2883887

                                                                    865 of 1521  
TI: Global biogeochemical cycles: Progress and problems.
AU: Hedges,-J.I.
AF: Sch. Oceanogr., WB-10 Univ. Washington, Seattle, WA 98195, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 67-93
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Progress in understanding global biogeochemical cycles has been made on many fronts of organic geochemical study over the last decade. Key questions, however, remain to be answered. These include the following: (1) Is kerogen completely remineralized during the weathering of sedimentary rocks? (2) What types of refractory biochemicals are made by plants? (3) What factors control export of organic matter from the land to the ocean? (4) What are the components, sources and fates of organic materials dissolved in seawater? (5) What types of organic substances accumulate in deltaic and coastal marine sediments? (6) Is better understanding of global biogeochemical cycles possible through new conceptual approaches?
AN: 2883870

                                                                    866 of 1521  
TI: Biomarker and molecular paleontology working group report.
AU: Farrington,-J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 51-65
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Organic matter in marine sediments originates from autochthonous primary production in the oceans and from allochthonous riverine and eolian contributions. Allochthonous inputs include organic matter of direct biological origin augmented by material from reworked geological sources such as weathered kerogens, petroleum seepages and hydrothermal vents. These diverse inputs of organic matter may survive unaltered, or may be modified and overprinted by contributions from secondary producers and by physicochemical transformation processes. Thus, the sedimentary organic matter is derived from organisms and geological sources either (a) selectively preserved, but otherwise unaltered, or (b) modified by biochemical activity and/or chemical alteration. A major goal of molecular paleontologists is to deconvolute these signals in the sedimentary record and to assess, interpret and distinguish them in terms of their response to paleoenvironmental and paleoecological factors and to variations in biogeochemical cycles. These objectives must be addressed at a range of spatial and temporal scales, with broad emphases on both regional and global issues and on both contemporary and ancient sediments.
AN: 2883851

                                                                    867 of 1521  
TI: Macromolecular organic matter working group report.
AU: Farrington,-J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 39-50
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: In the following discussion, macromolecular organic matter (MOM) is defined as organic substances larger than biochemical monomers (e.g. simple amino acids and sugars) and ranging up to aqueous colloids. In the broadest sense, MOM may consist of loosely aggregated assemblages of smaller molecules as well as discrete covalently bonded structures. It is thought that MOM probably is composed of both biopolymers and humic substances, which are degradation products of biopolymers. Although MOM can occur either in dissolved or particulate form, the bulk of the following discussion deals with the MOM component of dissolved organic matter (DOM) in seawater, which by definition is not removed by less than 0.5  mu m filters. The study of MOM is crucial for understanding organic matter sources and sinks in the ocean as well as for delineating the vast number of transformation processes that organic substances undergo within the water column and sediments. Although largely uncharacterized as yet, MOM apparently accounts for the major portion of DOM, which is the largest reservoir of organic carbon in the sea and comparable in carbon content to atmospheric CO sub(2). MOM thus is important in global biogeochemical cycles including the partitioning of CO sub(2) among the various active reservoirs.
AN: 2883828

                                                                    868 of 1521  
TI: Water column working group report.
AU: Farrington,-J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 15-25
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Organic matter in the oceanic water column is one of the most interactive organic pools on the Earth's surface because of the interfaces between the ocean and the atmosphere, sediments, and biota. With this in mind, three general questions are of central importance to improving our understanding of the role that water column processes play in oceanic chemistry. (1) What is the nature of oceanic organic matter? (2) What processes control water column organic chemistry? (3) How does water column organic chemistry in turn influence other oceanographic processes and global biogeochemical cycles?
AN: 2883791

                                                                    869 of 1521  
TI: (Carbonate sediments of the continental shelves of Paraiba State.).
OT: Sedimentos carbonaticos da plataforma continental do Estado da Paraiba
AU: Barbosa,-C.M.B.M.
AF: Dep. Quim. Aplicada, Univ. Fed. Pernambuco, 5000 Recife, PE, Brazil
SO: TRAB.-OCEANOGR.-UNIV.-FED.-PERNAMBUCO. 1989. vol. 20, pp. 125-144
LA: Portuguese
ER: M (Marine)
AB: Carbonate sediments stemming from massive and ramified coralline algae, together with significant amount of Halimeda , lie on the narrow continental shelf of the engaged area. The terrigenous sediments which are the mostly composed of quartz sands with organic fragments strech along the shelf boundary to a depth of 15 meters. The calcium carbonate content is very high and increases towards the offshore area. The lack of an important terrigenous sedimentation together with the favorable climatic and oceanographic conditions are responsible for the concentration of this significant organic calcareous deposit.
AN: 2882541

                                                                    870 of 1521  
TI: Disturbance of the phosphorus cycle: A case of indirect effects of human activity.
AU: Caraco,-N.F.
AF: Inst. Ecosyst. Stud., The Mary Flagler Cary Arbor., Box AB, Millbrook, NY 12545, USA
SO: TRENDS-ECOL.-EVOL. 1993. vol. 8, no. 2, pp. 51-54
LA: English
ER: F (Freshwater)
AB: Phosphorus (P) often limits primary productivity of aquatic systems. Humans have altered the P cycle in aquatic systems, directly, by mining P-rich rock, and indirectly, through the manipulation of other element cycles and the alteration of aquatic food webs. Aquatic ecologists are becoming increasingly aware of the importance of these indirect alterations to biogeochemical cycles. Quantitative predictions of these indirect effects will be an important focus of future studies.
AN: 2881168

                                                                    871 of 1521  
TI: Nutrient transformations in sediments as influenced by oxygen supply.
AU: Moore,-P.A.,Jr.; Reddy,-K.R.; Graetz,-D.A.
AF: Southeast Res. and Ext. Cent., Univ. Arkansas, P.O. Box 3508, Monticello, AR 71655, USA
SO: J.-ENVIRON.-QUAL. 1992. vol. 21, no. 3, pp. 387-393
LA: English
ER: F (Freshwater)
AB: The oxidation status of sediments greatly affects biogeochemical processes. The objective of this study was to determine the influence of various levels of O sub(2) on nutrient transformations in lake sediments. Decomposition of sediment organic matter was evaluated under varying levels of O sub(2). Bulk sediment samples obtained from a hypereutrophic lake in central Florida were incubated in stirred microcosms at 25 degree C for 100 d at four O sub(2) levels. The O sub(2) levels were accomplished by bubbling N sub(2) containing 0, 0.2, 2.0, and 20.0% O sub(2) through the stirred suspensions.
AN: 2880922

                                                                    872 of 1521  
TI: Protecting tropical and subtropical coastal waters: A resource for future generations.
AU: Arrhenius,-E.
AF: Natl. Resour. Manage. Inst. Frescati Backe, Stockholm Univ., S-106 91 Stockholm, Sweden
CO: Royal Colloquium on Environment Development and Industry, Solna (Sweden), 12-14 Aug 1992
SO: AMBIO. 1992. vol. 21, no. 7, pp. 488-490
LA: English
AB: The scope of the colloquium was to cover the disruptive effects on marine-food-producing ecosystems caused by the use of water as a transport medium for organic waste as a transport medium for organic waste, living micro-organisms, and nutrient supporting growth of living organisms, emanating mainly from households in urban areas, and from agricultural activities.
AN: 2880386

                                                                    873 of 1521  
TI: Sulfur pool sizes and stable isotope ratios in Humex peat before and immediately after the onset of acidification.
AU: Morgan,-M.D.
AF: Dep. Biol., Rutgers Univ., Camden, NJ 08102, USA
SO: ENVIRON.-INT. Gjessing,-E.T.;Petersen,-R.C.,Jr.-eds. 1992. vol. 18, no. 6, pp. 545-553
NT: Spec. Iss.: Huemor Humex: Exp. acidification, catchment, humic lakes.
LA: English
ER: F (Freshwater)
AB: Total nonsulfate sulfur (TS), reduced inorganic sulfur (RIS), ester sulfate (ES) and carbon bonded sulfur (CBS) pool sizes, and TS and RIS stable sulfur isotopes were examined in peat cores from control and experimental sites within the Skjervatjern catchment before and 8.5 months after the onset of acidification. The total amount of excess sulfate added to the catchment up to this point was less than expected due to mechanical problems. There have been no observable effects on sulfur cycling within the peat soils. The results from this study, however, provide insight into the natural factors controlling sulfur cycling in this system and suggest that dissimilatory sulfate reduction plays a key role.
AN: 2878595

                                                                    874 of 1521  
TI: Cycle of halocarbons in the air-water phase.
AU: Yamasaki,-T.; Oki,-N.; Okuno,-T.
AF: Hyogo Prefectural Inst. Environ. Sci., 3-1-27 Yukihira-cho, Suma-ku, Kobe 654, Japan
CO: 1. IAWPRC Int. Symp., Otsu City (Japan), 25-28 Nov 1991
SO: HAZARD-ASSESSMENT-AND-CONTROL-OF-ENVIRONMENTAL-CONTAMINANTS-IN-WATER. Matsui,-S.-ed. 1992. vol. 25, no. 11 pp. 33-39
ST: WATER-SCI.-TECHNOL. vol. 25, no. 11
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Halocarbons are widely distributed in environment: atmosphere, hydrosphere, lithosphere and biosphere. This report presents the data on the cycle of halocarbons in air-water phase. Low-boiling-point halocarbons were monitored and about 10 kind of substances which include chlorofluorocarbon (CFC) were detected in the environment. The concentrations of halocarbons in air are influenced by weather conditions, especially by wind speed. Three CFCs, CFC-11, CFC-12 and CFC-113, were detected at the level of 0.18-1.70 ppb on the day (wind speed 0-1 m/sec), and 0.05-0.40 ppb (5-10 m/sec). Other halomethanes, chloroform and carbon tetrachloride, were detected at the level of 0.06-0.72 ppb and 0.03-0.06 ppb; a haloethane, 1,1,1-trichloroethane, was 0.50-5.3 ppb and 0.12-0.95 ppb; and haloethylenes, trichloroethylene and tetrachloroethylene were 0.02-4.1 ppb and 0.01-1.8 ppb on days of wind speed below 1 m/sec and 5-10 m/sec, respectively. Substances found in air were also detected in water phase. Concentrations of above-mentioned halocarbons in water were at the level of 0.001-0.0095 ppb in river water, 0.002-0.06 ppb in ground water, 0.001-0.036 ppb in seawater, and 0.001-0.53 ppb in rain water. In comparison with concentration of halocarbons of environmental measurement and estimation value by using the predictive fate model of chemical substances, haloethanes and haloethylenes in air exceeded the value of estimation. On the other hand, halomethanes in air almost agreed with its value, and in water phase were quite similar to the estimation.
AN: 2871242

                                                                    875 of 1521  
TI: The Ecology of Mangrove and Related Ecosystems.
AU: Jaccarini,-V.; Martens,-E.-(eds.)
CO: The Ecology of Mangrove and Related Ecosystems, Mombasa (Kenya), 24-30 Sep 1990
SO: HYDROBIOLOGIA. 1992. vol. 247, no. 1-3, 266 pp
LA: English
ER: M (Marine); B (Brackish)
AB: The international symposium on The Ecology of Mangrove and Related Ecosystems, Mombasa, Kenya, 24-30 September, 1990, was organized by the Department of Zoology, University of Nairobi, in collaboration with the Kenya Marine and Fisheries Research Institute, and the Regional Dispatch Centre of the Regional Cooperation in Scientific Information Exchange in the West Indian Ocean, Mombasa, Kenya. Scientific investigation of the mangrove ecosystems came from all the main tropical marine areas of the globe, representing twenty-three countries, in West and Eastern Africa, South and Southeast Asia, Central and South America, and Australia. The thirty papers published in this volume were selected from seventy presented at the symposium. It is recognized that the mangroves have intimate and complex linkages with other coastal systems, notably seagrass beds and coral reefs. So, starting from the mangrove forest and its users at the interface between the terrestrial, freshwater and marine environments, the papers presented proceed to the fully submerged seagrasses and further out to the corals. The nature of the coupling between the different systems was touched on at the symposium, but stands out as a serious gap in our knowledge. Next, chemical and physical processes which constitute the mechanisms of linkage received attention. Human uses and abuses of the ecosystems formed the last major topic of the symposium.
AN: 2870705

                                                                    876 of 1521  
TI: (Experimental study on the transfer of plasmid genes between enterobacteria in the marine environment.).
OT: Etude experimentale du transfert de genes plasmidiques entre les enterobacteries dans l'environnement marin
AU: Gauthier,-M.J.
AF: INSERM, Unite 303 "Mer et Sante," 1 Ave. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991.  CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991. UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. pp. 61-76
ST: MAP-TECH.-REP.-SER.
LA: French
ER: M (Marine)
AN: 2868421

                                                                    877 of 1521  
TI: (Experimental study on the transfer of plasmid genes between enterobacteria in seawater, sediments and the digestive tracts of marine invertebrates.).
OT: Etude experimentale du transfert de genes plasmidiques entre enterobacteries dans l'eau de mer, les sediments et le tractus digestif des invertebres marins
AU: Gauthier,-M.J.; Martin,-Y.; Torregrossa,-V.
AF: INSERM Unite 303 "Mer et Sante," 1 Ave. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991.  CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991. UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. no. 63 pp. 29-60
ST: MAP-TECH.-REP.-SER. no. 63
LA: French
ER: M (Marine)
AN: 2868390

                                                                    878 of 1521  
TI: (The influence of osmoregulation mechanisms on the survival and adaptation of enteric bacteria in the marine environment.).
OT: Influence des mecanismes d'osmoregulation sur la survie et l'adaptation des bacteries enteriques dans l'environnement marin
AU: Gauthier,-M.J.
AF: INSERM Unite 303 "Mer et Sante," 1 Ave. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991.  CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991. UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. pp. 17-28
ST: MAP-TECH.-REP.-SER.
LA: French
ER: M (Marine)
AN: 2868349

                                                                    879 of 1521  
TI: Seasonal variability in primary production and particle flux in the northwestern Sargasso Sea: U.S. JGOFS Bermuda Atlantic Time-Series Study.
AU: Lohrenz,-S.E.; Knauer,-G.A.; Asper,-V.L.; Tuel,-M.; Michaels,-A.F.; Knap,-A.H.
AF: Univ. Southern Mississippi, Cent. Mar. Sci., Stennis Space Cent., MS 39529, USA
SO: DEEP-SEA-RES. 1992. vol. 39, no. 7-8A, pp. 1373-1391
LA: English
ER: M (Marine)
AB: The relationship between primary production and sediment trap-derived downward flux of particulate organic matter was characterized over a 2 year period at the U.S. JGOFS Bermuda Atlantic Time-series Study (BATS) site to evaluate the importance of temporal variations in upper ocean biogeochemical processes. Water column-integrated primary production ( integral of PP), determined once each cruise using  super(14)C incubations (in situ dawn-to-dusk), peaked in late winter/early spring of both 1989 and 1990. Smaller increases in  integral of PP also occurred in July 1989 and October-December 1990. Annual  integral of PP was 9.2 mol C m super(-2)/y in 1989 and 12 mol C m super(-2)/y in 1990. This was higher than the 1959-1963 annual average (6.8 mol C m super(-2)/y) determined at Station "S" located approximately 50 km northwest of the BATS site.
AN: 2865866

                                                                    880 of 1521  
TI: Trace elements in lacustrine sediments.
OT: Elementi in traccia e sedimenti lacustri
AU: Baudo,-R.; Ferrari,-A.
SO: DIRECTOR'-S-REPORT-ON-THE-SCIENTIFIC-ACTIVITY-OF-THE-INSTITUTE-FOR-YEAR-1988.  RELAZIONE-DEL-DIRETTORE-SULL'-ATTIVITA-SCIENTIFICA-DELL'-ISTITUTO-NELL'-ANNO-1988. Bernardi,-R.-de-ed. Istituto-Italiano-di-Idrobiologia,-Verbania-Pallanza-Italy no. 26 no. 1990, pp. 54-56
ST: DOC.-IST.-ITAL.-IDROBIOL. no. 26
LA: Italian
ER: F (Freshwater)
AB: Sediments from several Italian lakes have been sampled with the objective of relating their chemical composition to the geochemistry of the respective drainage basins and eventually spotting possible modifications of the biogeochemical cycles due to human activities. In 1988, the study was extended to Lake Garda and Lake Vegoritis, Greece. For each lake, several grab samples were collected to carefully depict the spatial distribution in recent sediments, and additional cores were taken for describing the temporal variations of element sedimentation. In total, almost 200 samples of sediments were obtained which after processing (drying, sieving, milling and dissolution), are to be analyzed for P, Zn, Ni, Mn, Fe, Cr, V, Cu, Ti, C, N, Pb, Cd, Hg, As, and possibly for other elements (Na, K, Ca, Mg, Co, Mo, Sb, Tl, and so on), by means of atomic absorption, X-ray fluorescence and nuclear activation analysis.
AN: 2862176

                                                                    881 of 1521  
TI: Suspended matter in Luoyuan Bay seawater, Fujian.
AU: Guo,-Laodong; Hong,-Huasheng
AF: Xiamen Univ., Xiamen 361005, People's Rep. China
SO: OCEANOL.-LIMNOL.-SIN.-HAIYANG-YU-HUZHAO. 1992. vol. 23, no. 1, pp. 83-89
LA: Chinese
ER: M (Marine)
AB: Distributions and features of total suspended matter (TSM) in Luoyuan Bay seawater were studied during six cruises from November 1986 to September 1987. It was found that resuspension of sediments takes an important role in controlling the distribution of TSM in winter. However, the distribution of TSM in summer depends on biological processes and river inputs. The chemical compositions of the particles also showed seasonal variations. The correlation between TSM and particulate organic carbon (POC) showed that the content of POC was related to biological activities when the primary production was enhanced from May to September, whereas the content of POC was controlled by the terrestrial input as the primary production was low from November to March. Increment of TSM caused by resuspension can result in the decline of transparency and further affects the level of primary production of the bay. But, it can also increase the availability of nutrients by releasing them from the resuspended particles. The ratio of POC flux to the primary production is about 67-85% in summer estimated from the sediment traps. POC from the primary producers settling to the sediments can play an important role in the detritus foodchain in Luoyuan Bay seawater.
AN: 2861458

                                                                    882 of 1521  
TI: Ecology of sea ice biota. 2. Global significance.
AU: Legendre,-L.; Ackley,-S.F.; Dieckmann,-G.S.; Gulliksen,-B.; Horner,-R.; Hoshiai,-T.; Melnikov,-I.A.; Reeburgh,-W.S.; Spindler,-M.; Sullivan,-C.W.
AF: Dep. Biol., Univ. Laval, Quebec, PQ G1K 7P4, Canada
SO: POLAR-BIOL. 1992. vol. 12, no. 3-4, pp. 429-444
NT: Bibliogr.: 175 ref.
LA: English
ER: M (Marine)
AB: In this paper, new estimates of Arctic and Antarctic production of biogenic carbon are derived, and differences as well as similarities between the two oceans are examined. In ice-covered seas, high algal concentrations (blooms) occur in association with several types of conditions. Blooms often lead to high sedimentation of intact cells and faecal pellets. In addition to ice-related blooms, there is progressive accumulation of organic matter in Arctic multi-year ice, whose fate may potentially be similar to that of blooms. A fraction of the carbon fixed by microalgae that grow in sea ice or in relation to it is exported out of the production zone. This includes particulate material sinking out of the euphotic zone, and also material passed on to the food web. Pathways through which ice algal production does reach various components of the pelagic and benthic food webs, and through them such top predators as marine mammals and birds, are discussed.
AN: 2859334

                                                                    883 of 1521  
TI: Protist abundance and carbon concentration during a Phaeocystis -dominated bloom at an Antarctic coastal site.
AU: Davidson,-A.T.; Marchant,-H.J.
AF: Australian Antarctic Div., Channel Highw., Kingston, Tas. 7050, Australia
SO: POLAR-BIOL. 1992. vol. 12, no. 3-4, pp. 387-395
NT: Bibliogr.: 60 ref.
LA: English
ER: M (Marine)
AB: Changes in the concentrations of bacteria, phytoplankton, protozoa, dissolved organic carbon (DOC) particulate organic carbon (POC), particulate carbohydrate (PCHO) and particulate organic nitrogen (PON) were followed throughout the summer at an Antarctic coastal site. The colonial prymnesiophyte Phaeocystis pouchetii  was the first major phytoplankton species to bloom, reaching concentrations of 6 x 10 super(7) cells/l and remained numerically dominant for most of the summer. During the P. pouchetii) bloom the concentration of most other autotrophs did not increase. Microheterotroph abundance peaked during or immediately after the Phaeocystis  bloom. Their peak coincided with very high concentrations of organic carbon, particularly DOC which exceeded 100 mg/l, and low bacterial abundance. Maximum bacterial abundance was reached after the decline in microheterotroph numbers.
AN: 2859254

                                                                    884 of 1521  
TI: Dynamics of nutrients and phytoplankton, and fluxes of carbon, nitrogen and silicon in the Antarctic Ocean.
AU: Treguer,-P.; Jacques,-G.
AF: Inst. Etudes Mar., URA CNRS 1513, 6 Ave. Le Gorgeu, F-29287 Brest-Cedex, France
SO: POLAR-BIOL. 1992. vol. 12, no. 2, pp. 149-162
NT: Bibliogr.: 124 ref.
LA: English
ER: M (Marine)
AB: Four major functional units have been identified in the Southern Ocean and the mechanisms that control the dynamics of nutrients and phytoplankton are detailed for the different sub-systems. The very productive Coastal and Continental Shelf Zone (CCSZ, 0.9 M km super(2)) can experience severe macronutrient depletion paralleling intense diatom-dominated phytoplankton blooming (maximum > 8 mg Chl a m super(-3)) at the ice edge. In the Seasonal Ice Zone (SIZ, 16 M km super(2)), dramatic variations in the hydrological structure occur in surface waters during the spring to summer retreat of the pack-ice, changing from a well-mixed system to a stratified one within the reaches of the ice edge. Grazing activity of euphausiids limits phytoplankton biomass to a moderate level (Chl a maximum around 4 mg m super(-3)).
AN: 2859201

                                                                    885 of 1521  
TI: Stable carbon isotope composition, depth distribution and fate of macroalgae from the Antarctic Peninsula region.
AU: Fischer,-G.; Wiencke,-C.
AF: Fachber. Geowiss., Univ. Bremen, Klagenfurter Str., D-W 2800 Bremen, FRG
SO: POLAR-BIOL. 1992. vol. 12, no. 3-4, pp. 341-348
NT: Bibliogr.: 47 ref.
LA: English
ER: M (Marine)
AB: Stable carbon isotope composition of macroalgae collected at King George Island (Antarctica) ranged from about -8 ppt to -34 ppt. We hypothesize that the  delta  super(13)C values are related to the depth distribution species inhabiting greater depth had much lower values (around -30 ppt) compared to species from shallower waters (around -17 ppt). Isotopic studies on sediment trap samples from the King George Basin (2,000 m deep) revealed that benthic macroalgae contributed strongly to the total organic carbon pool of the deeper basin waters during austral spring and summer. Fragments of brown macroalgae (Desmarestiales) were detected in microscopical analyses of semi-thin sections of sediment samples from the Bransfield Strait. Possible mechanisms regarding the erosion of benthic macroalgae and their transport to the deeper water and to the sediment are summarized.
AN: 2859169

                                                                    886 of 1521  
TI: Bacterial transfer of methane and detritus; implications for the pelagic carbon budget and gaseous release.
AU: Hessen,-D.; Nygaard,-K.
AF: Norwegian Inst. Water Res., P.O. Box 69, Korsvoll, N-0808 Oslo 8, Norway
CO: 5. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Environments, Helsingoer (Denmark), 18-23 Aug 1991
SO: MICROBIAL-ECOLOGY-OF-PELAGIC-ENVIRONMENTS. Bjoernsen,-P.K.;Riemann,-B.-eds. STUTTGART-FGR SCHWEIZERBART'-SCHE-VERLAGSBUCHHANDLUNG 1992. no. 37 pp. 139-148
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 37
LA: English
AB: Phytoplankton exudate release is generally considered the most important source of carbon for pelagic bacteria in aquatic communities, but in many localities allochthonous inputs may be the main source of carbon. In a well studied humic lake, detrital compounds fueled more than 80% of bacterial secondary production. The lake also supported a vigorous methane production. Methane was oxidized over the entire water column above the anaerobic layer, and preliminary data suggest that carbon fixed by methanotrophs may be in the same order of magnitude as bacterial secondary production. Thus the utilization of detritus and oxidation of methane may be important sources of carbon for bacteria and thus serve as "new" inputs of carbon to pelagic food webs. Such allochthonously influenced lakes may also be important gas conduits to the atmosphere due to oxidation of organic compounds and methane.
AN: 2858606

                                                                    887 of 1521  
TI: Large lakes and their sustainable development.
AU: Tilzer,-M.M.; Bossard,-P.
AF: Limnol. Inst., Univ. Konstanz, Mainaust. 212, D-7750 Konstanz, FRG
SO: AQUAT.-SCI. 1992. vol. 54, no. 2, pp. 91-103
LA: English
ER: F (Freshwater)
AB: This contribution has been edited from a working document, prepared by invited scientists attending a workshop in Konstanz, Germany, on the importance of external perturbations for short- and long-term changes in large lakes ecosystems, held from 21 to 26 October, 1991. It tries to assess our current understanding of the most important processes involved in the functioning of large lakes and to identify the currently most urgent research priorities in the fields of land-water interactions, physical processes, biogeochemistry and nutrient relations, remote sensing, biological interactions in food webs, and long-term monitoring programs.
AN: 2857149

                                                                    888 of 1521  
TI: Using parallel salinity and temperature profiles for calculations of estuarine fluxes with reference to the Baltic proper.
AU: Rahm,-L.; Wulff,-F.
AF: Dep. Water and Environ. Stud., Linkoeping Univ., S-581 83 Linkoeping, Sweden
SO: NETH.-J.-SEA-RES. 1992. vol. 29, no. 4, pp. 281-289
LA: English
ER: M (Marine)
AB: A diagnostic advection-diffusion equation system in a "natural coordinate" frame of reference is investigated in order to improve its robustness. The dependence of the leading-order solutions on higher-order features of the hydrographic data has been decreased and a differential equation with an analytical solution is obtained. The properties of the lowest-order equation are compared with previous studies where the undegenerated equations were used to estimate the distribution of both the diapycnal salt flux and the oxygen consumption within the Baltic proper. The agreement found is within the acceptable bounds. Finally a pilot study of a silicate budget of the Baltic proper has been performed.
AN: 2856920

                                                                    889 of 1521  
TI: Nitrogen dynamics at the VERTEX time-series site.
AU: Harrison,-W.G.; Harris,-L.R.; Karl,-D.M.; Knauer,-G.A.; Readlje,-D.G.
AF: Biol. Oceanogr. Div., Dep. Fish. and Oceans, Bedford Inst. Oceanogr., Box 1006, Dartmouth, NS B2Y 4A2, Canada
SO: DEEP-SEA-RES. 1992. vol. 39, no. 9A, pp. 1535-1552
LA: English
ER: M (Marine)
AB: Euphotic zone concentrations and fluxes of nitrate, ammonium, particulate and dissolved organic nitrogen were measured over an 18 month period at the VERTEX time-series site in the oligotrophic northeast Pacific (33 degree N, 139 degree W). Variations in all N-forms were significant but not clearly linked to the temporal hydrographic cycle. Inorganic-N-uptake (nitrate + ammonium) from  super(15)N tracer experiments generally paralleled primary productivity variations, peaking in summer; ammonium accounted for most of the uptake ( similar to 90%) and temporal variability. Comparisons of  super(15)N results with estimates of autotrophic N-uptake from  super(14)C incorporation into protein suggest that as much as 40% of the annual inorganic-N uptake was due to microheterotrophs; peak heterotrophic N-uptake occurred in summer when heterotrophic biomass was at its maximum. Nitrate uptake (new production) was less variable than ammonium uptake and annually equivalent to particulate nitrogen export from sediment traps. Dissolved organic-N (DON) represented the largest and most variable N-pool, accounting for 80-90% of the total nitrogen in the euphotic zone.
AN: 2856628

                                                                    890 of 1521  
TI: The carbon balance during the 1989 spring bloom in the North Atlantic Ocean, 47 degree N, 20 degree W.
AU: Bender,-M.; Ducklow,-H.; Kiddon,-J.; Marra,-J.; Martin,-J.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Kingston, RI 02881, USA
SO: DEEP-SEA-RES. 1992. vol. 39, no. 10A, pp. 1707-1725
LA: English
ER: M (Marine)
AB: The authors report on studies of the carbon balance of the upper water column, done as part of the JGOFS North Atlantic Bloom Experiment, over a 13-day period, at 47 degree N, 20 degree W, during the 1989 spring phytoplankton bloom. Gross carbon production was calculated from data on  super(18)O gross O sub(2) production and from  super(14)C production as well. Net carbon production was calculated from net O sub(2) production rates measured in vitro, as well as from changes in the inventories of nutrients and O sub(2) along with O sub(2) evasion rates by gas exchange. Gross carbon production during this period was measured to be 1.83 mol m super(-2), and net production was 0.68 mol m super(-2). Of this net carbon production, 0.30 mol m super(-2) was stored in the euphotic zone as particulate organic carbon, and 0.09 mol m super(-2) rained out to depths > 150 m. The remainder was remineralized to DIC in the 50-150 m depth interval, with perhaps some DOC storage in the upper 150 m.
AN: 2854524

                                                                    891 of 1521  
TI: Influence of carbon availability on denitrification in the central Baltic Sea.
AU: Brettar,-I.; Rheinheimer,-G.
AF: NIWAR, Water Qual. Cent., P.O. Box 11-115, Hamilton, New Zealand
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 6, pp. 1146-1163
LA: English
ER: M (Marine)
AB: Denitrification was investigated in the Baltic proper at two stations with different conditions in the deep water. The Gotland Deep was examined as an example of a basin with anoxic, H sub(2)S-containing deep water and station T was taken as an example of low-oxygen (< 0.2 ml/liter). sulfide-free deep water. Denitrification was measured by the acetylene blockage method; in addition, N sub(2)O reduction was followed in samples without acetylene. To shed light on the factors limiting denitrification, we compared in situ rates to denitrification after adding nitrate or electron donors. Denitrification was restricted to the layer of the oxic-anoxic interface in the Gotland Deep and to the water layer near the sediment of station T. For both stations it could be shown that denitrification was not limited by nitrate availability. A lack of available organic C seemed to limit denitrification rates and growth of denitrifiers. As a result of limitation in the water column, denitrification was restricted to energy-rich interfaces.
AN: 2854359

                                                                    892 of 1521  
TI: The phosphorus cycle in coastal marine sediments.
AU: Sundby,-B.; Gobeil,-C.; Silverberg,-N.; Mucci,-A.
AF: Univ. Quebec, INRS-Oceanol., Cent. Oceanogr. Rimouski, 310 Allee des Ursulines, Rimouski, PQ G5L 3A1, Canada
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 6, pp. 1129-1145
LA: English
ER: M (Marine); B (Brackish)
AB: Approximately half of the sedimentation flux of particulate phosphorus in the Laurentian Trough in The Gulf of St. Lawrence is mobilized within the sediment and returned to the water column. In the oxidizing surface sediment, a major portion of the sedimentation flux of organic phosphorus is mineralized, and the released phosphate is partitioned between the pore water and surface adsorption sites. Surface-adsorbed phosphate is released to the pore water as needed to replace dissolved phosphate that escapes to the overlying water. Most of the phosphate is released deeper in the sediment column from iron oxides undergoing reduction. The nonmobilized phosphorus, which is buried with the accumulating sediment, appears to consist mostly of stable minerals such as apatite. The concentration of dissolved phosphate in sediment pore waters increases sharply across the sediment-water interface from 2  mu mol PO sub(4) liter super(-1) in the bottom water to 6  plus or minus  3  mu mol PO sub(4) liter super(-1) in the top centimeter, remains almost constant at this value down to 5-15 depth, and then increases rapidly with further depth.
AN: 2854338

                                                                    893 of 1521  
TI: Role of benthos in the migration of microelements in Zaporozhye Reservoir.
AU: Varenko,-N.I.; Zagubizhenki,-N.I.; Gaydash,-Yu.K.
AF: Inst. Biol., Dnepropetrovsk Univ., Ukraine
SO: HYDROBIOL.-J. 1991. vol. 27, no. 3, pp. 90-95
LA: English
ER: F (Freshwater)
AB: Benthic organisms of Zaporozhye Reservoir, Ukraine, differ in their ability to accumulate microelements; the influencing factors are species, season of the year, and the concentrations of the microelements in the abiotic components of the ecosystem. The concentration of the metals by the benthos are, respectively, 200-7,000 for manganese, 900-11,000 for zinc, 300-5,000 for copper, 250-5,800 for lead, and 150-1,100 for cobalt. Organisms that concentrate particular elements are identified. The roles of certain species of benthos in the biological migration of metals in the abiotic components of the reservoir's ecosystem have been identified. The largest amounts are set into circulation by the mollusks.
AN: 2853462

                                                                    894 of 1521  
TI: Biogeochemical cycles of specific pollutants (activity K). Final report on project on survival of pathogenic organisms in seawater.
CA: UNEP Mediterranean Action Plan, Athens (Greece)
WHO, Geneva (Switzerland)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1991. no. 55, 96 pp
NT: Title also in Fr.
LA: English
ER: M (Marine)
AB: Microorganisms in sewage are dispersed by turbulent diffusion when discharged into the sea. Physiological damage may be sublethal or cause death of the cell. This damage or stress can be studied by observing either the bacterial structural disorganization or their inability to carry out a determined metabolic function in a selective medium. However, these stress cells can be developed in culture media which do not contain inhibitory substances. The importance of the study of the physiological damage to pathogenic cells is based on the non-detection of these cells in the performance of standard microbiological tests, which are based on the examination of selective culture media. A large variety of environmental conditions or factors exist which can kill, damage or simply cause the disappearance of microorganisms from the environment. These include physical, chemical and biological processes.
AN: 2853189

                                                                    895 of 1521  
TI: Factors controlling the concentration of particulate carbohydrates and amino acids in the Parana River.
AU: Kempe,-S.; Depetris,-P.J.
AF: Inst. Biogeochem. and Mar. Chem., Univ. Hamburg, Bundesstr. 55, D-2000 Hamburg, FRG
SO: HYDROBIOLOGIA. 1992. vol. 242, no. 3, pp. 175-183
LA: English
ER: F (Freshwater)
AB: Particulate carbohydrates and particulate amino acids were determined in a set of samples from the Parana River, Argentina, covering a stretch of over 1300 km. To gain an understanding of the factors which control the concentrations of these organic compounds, a multivariate statistical approach was used (R-mode varimax factor analysis). This technique separated the influence of various sources of organic matter. The floodplain of the middle reach (about 900 km long and 20-30 km wide) was the most significant source controlling the concentrations of particulate carbohydrates (PCH), providing angiosperm debris, phytoplankton and grasses. Particulate amino acids (PAA) concentrations were determined markedly both by contributions from the Paraguay basin, and the lotic and lentic environments of the floodplain. Sugars single out forested tributary basins as sources of bacteria while amino acids point toward the Paraguay River as a major source of biodegraded material; heterotrophic processes, however, appear more clearly depicted with PAA than with PCH. A downstream increase of the PCH/PAA ratio suggests a larger consumption of PAA in the lowermost reaches.
AN: 2850355

                                                                    896 of 1521  
TI: The degradation of arsenobetaine to inorganic arsenic by sedimentary microorganisms.
AU: Hanaoka,-K.; Tagawa,-S.; Kaise,-T.
AF: Dep. Food Sci. and Technol., Shimonoseki Univ. Fish., Yoshimi-cho, Shimonoseki 759-65, Japan
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 623-628
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: M (Marine)
AB: Two growth media containing arsenobetaine ((CH sub(3)) sub(3) As super(+)CH sub(2)COO super(-)) were mixed with coastal marine sediments, the latter providing a source of microorganisms. The mixtures were kept at 25 degree C in the dark and shaken for several weeks under an atmosphere of air. The disappearance of arsenobetaine and the appearance of two metabolites were followed by HPLC. The HPLC-retention time of the first metabolite agreed with that of trimethylarsine oxide ((CH sub(3)) sub(3)AsO). The second metabolite was identified as arsenate (As(V)) using hydride generation/cold trap/GC MS analysis and thin layer chromatography. This is the first scientific evidence showing that arsenobetaine is degraded by microorganisms to inorganic arsenic via trimethylarsine oxide. The degradation of arsenobetaine to inorganic arsenic completes the marine arsenic cycle that begins with the methylation of inorganic arsenic on the way to arsenobetaine.
AN: 2849629

                                                                    897 of 1521  
TI: Sulfate-reduction process in sediments of Lake Kinneret, Israel.
AU: Hadas,-O.; Pinkas,-R.
AF: Kinneret Limnol. Lab., Israel Oceanogr. and Limnol. Res., P.O. Box 345, Tiberias 14102, Israel
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 295-301
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: F (Freshwater)
AB: Monomictic Lake Kinneret is stratified during summer and autumn, resulting in a hypolimnion rich in H sub(2)S (3-7 mg/l). In winter and spring every year a bloom of dinoflagellate Peridinium gatunense) produces an average biomass of 150,000 ton wet weight. Part of this biomass sinks to the hypolimnion and sediments where it is decomposed and mineralized, with some of the mineralization due to the activity of sulfate-reducing bacteria (SRB). The sulfate-reduction potential of the upper sediment layer at the deepest part of the lake (42 m) was measured. The activity of the enzyme arylsulfatase was also monitored. Rates of sulfate-reduction ranged from a minimum of 12 nmoles SO sub(4)@) super(2)-r)educed cm super(-3)/day in December before lake overturn to a maximum of 1673 nmoles SO sub(4)@) super(2)-r)educed cm super(-3)/day in July during stratification. These rates are considerably higher than those recorded from other freshwater lakes in the world and are probably limited more by the availability of organic matter than by sulfate concentrations.
AN: 2848175

                                                                    898 of 1521  
TI: Chromium cycling in natural water systems.
AU: Johnson,-C.A.; Sigg,-L.
AF: Inst. Water Resour. and Water Pollut. Control (EAWAG), Swiss Fed. Inst. Technol. (ETH) Zuerich, CH-8600 Duebendorf, Switzerland
CO: 4. IAEAC Workshop on Toxic Metal Compounds (Interrelation between Chemistry and Biology), Les Diablerets (Switzerland), 4 Mar 1991
SO: METAL-COMPOUNDS-IN-ENVIRONMENT-AND-LIFE,-4.-INTERRELATION-BETWEEN-CHEMISTRY-AND-BIOLOGY.-IN-MEMORIUM-OF-HANS-WOLFGANG-NUERNBERG. Merian,-E.;Haerdi,-W.-eds. NORHTWOOD,-MIDDLESEX-UK SCIENCE-AND-TECHNOL.-LETTERS 1992. pp. 73-80
NT: Special Supplement to Chemical Speciation and Bioavailability.
LA: English
ER: F (Freshwater)
AB: The chromium cycle in natural waters has received much attention in recent years with an emphasis on the controlling chemical processes. The dynamics of the Cr cycle was investigated in a seasonally anoxic lake, the Greifensee in Switzerland. The results show that Cr(VI) is removed from the water column by reduction and/or adsorption. Reduced Cr(III) is present in colloidal form and is not oxidised to Cr(VI). In other systems Cr(III) oxidation can be observed.
AN: 2847675

                                                                    899 of 1521  
TI: Hydrodynamical singularities as controls of recycled versus export production in oceans.
AU: Legendre,-L.; Fevre,-J.-Le
AF: Dep. Biol., Univ. Laval, Laval, PQ G1K 7P4, Canada
CO: Dahlem Workshop on Productivity of the Ocean: Present and Past, Berlin (Germany), 24-29 Apr 1988
SO: PRODUCTIVITY-OF-THE-OCEAN:-PRESENT-AND-PAST.-REPORT-OF-THE-DAHLEM-WORKSHOP-ON-PRODUCTIVITY-OF-THE-OCEAN:-PRESENT-AND-PAST,-BERLIN-1988,-APRIL-24-29. Berger,-W.H.;Smetacek,-V.S.;Wefer,-G.-eds. CHICHESTER-UK WILEY-INTERSCIENCE-PUBL. 1989. no. 44 pp. 49-63
ST: LIFE-SCI.-RES.-PAP. no. 44
LA: English
ER: M (Marine)
AB: Phytoplankton production in oceans is either recycled in the euphotic zone or exported to the remainder of the ecosystem. The fate of marine primary production is discussed within the framework of a conceptual model, which specifies 5 major bifurcations where part of the production may be channeled into export pathways: production of large versus small cells; sinking or not of large cells; grazing versus accumulation (and microphagy) of large cells; recycling of small cells in the microbial food loop or aggregation; and sinking versus accumulation (and microphagy) of aggregates. It is shown that hydrodynamical singularities play a major role at each bifurcation in favoring production export over in situ recycling, which influences both present marine ecosystems and geological records.
AN: 2846036

                                                                    900 of 1521  
TI: Management of the riparian zone to maximize accumulation of large woody debris in streams.
AU: Rabon,-M.W.; Weyrick,-R.
AF: Univ. New Hampshire, Durham, NH, USA
CO: 2. Joint Meet. of the Maine Div. of New England Soc. of American Foresters, Maine Chapter of the Wildlife Soc., and the Atlantic Int. Chapter of the American Fisheries Soc., Portland, ME (USA), 15-17 Mar 1989
SO: FOREST-AND-WILDLIFE-MANAGEMENT-IN-NEW-ENGLAND-WHAT-CAN-WE-AFFORD?. PORTLAND,-ME-USA UNIV.-OF-MAINE-COLL.-OF-FOREST-RESOURCES 1989. no. 36 pp. 183-189
ST: MISC.-REP.-ME.-AGRIC.-EXP.-STN. no. 36
NT: Also as: Coll. For. Resour. CFRU Inf. Rep. No. 21. AIC 100.M28M.
RN: SAF 89-05 (8905)
LA: English
ER: F (Freshwater)
AB: In response to the U.S. Forest Service "Rise to the Future" program, the White Mountain (New Hampshire) and Green Mountain (Vermont) National Forests placed increased emphasis on fisheries management. As part of this initiative a cooperative agreement was developed with the Agricultural Experiment Station, University of New Hampshire to analyze alternative management prescriptions in appropriate riparian zones with the objective of increasing recruitment of large woody debris in streams to enhance fish habitat. The riparian zone and the role of large woody debris are discussed as well as the cooperative agreement goals and how the growth model, FIBER, will be used.
AN: 2841450

                                                                    901 of 1521  
TI: Modeling phosphorus cycling in a well-mixed coastal plain estuary.
AU: Lebo,-M.E.; Sharp,-J.H.
AF: Div. Environ. Stud., Univ. California, Davis, CA 95616, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1992. vol. 35, no. 3, pp. 235-252
LA: English
ER: M (Marine); B (Brackish)
AB: Phosphorus cycling in the Delaware Estuary was examined using numerical methods to calculate fluxes and estimate net regeneration. In the tidal river, the flux of total phosphorus (TP) increased threefold compared to Delaware River due to municipal inputs, with most of TP flux as dissolved inorganic phosphate (DIP, 56-59%). A mass balance for TP in the river indicated that a large fraction (44-67%) of TP inputs was retained mainly through geochemical processes. Phosphorus cycling in Delaware Bay, in contrast, was dominated by biological uptake and recycling. Within the bay, DIP input from the tidal river was transformed into phytoplankton biomass. The biological dominance of P cycling in the bay resulted in strong seasonal variations in TP flux. Throughout the year, except during the spring, regenerated DIP was sufficient to supply 102  plus or minus  19, 94  plus or minus  10, and 95  plus or minus  6% of phytoplankton P-demand in the upper, middle, and lower bay respectively. During the spring, there was an imbalance between uptake and regeneration resulting in DIP depletion. 71-97% of apparent regeneration occurred within the water column, with sediment DIP release contributing an additional 3-25%. On an annual basis, 84% of TP entering the salinity gradient of the estuary was exported to coastal waters.
AN: 2841131

                                                                    902 of 1521  
TI: Structural and behavioral characteristics of a commercial humic acid and natural dissolved aquatic organic matter.
AU: Grasso,-D.; Chin,-Y.-P.; Weber,-W.J.,Jr.
AF: Dep. Civil Eng., Univ. Connecticut, Storrs, CT 06269-3037, USA
SO: CHEMOSPHERE. 1990. vol. 21, no. 10-11, pp. 1181-1197
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Dissolved organic matter (DOM) from two natural surface water sources and a commercial humic acid were analyzed using gel-permeation chromatography, high pressure reverse phase liquid chromatography, and  super(1)H-NMR spectroscopy. Results from the chromatographic studies show that the DOM of two natural waters consisted primarily of relatively low molecular weight, polar organic constituents, while large and relatively nonpolar macromolecules comprised a significant fraction of the commercial humic acid. Based upon these composite results of the several different types of analysis employed, it is evident that the humic acid examined, and possibly others prepared in the same way, contain molecular structures which exhibit physical and chemical properties that do not reflect the true nature of DOM in real aquatic systems.
AN: 2838869

                                                                    903 of 1521  
TI: US Joint Global Ocean Flux Study program.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 57-59
NT: Spec. iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: The ocean's role in the global carbon cycle has attracted the interest of scientists from diverse disciplines for more than half a century, an interest sharpened in recent years by concerns about the effects of human activity upon atmospheric levels of carbon dioxide (CO sub(2)) and other greenhouse gases. The Joint Global Ocean Flux Study (JGOFS) builds on accumulated knowledge about the ocean's chemical, biological, and physical processes to increase understanding of the ocean carbon cycle. The program has two primary goals: to determine at a global level the processes that control the movement of carbon and other biologically active elements in the ocean and the way this cycling interacts with the atmosphere, the ocean margins, and the seafloor; and to improve our ability to make global-scale predictions of the likely response of ocean processes to changes in climate associated with human activities.
AN: 2837593

                                                                    904 of 1521  
TI: Biogeochemical processes on the seafloor.
AU: Sayles,-F.L.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 68-75
NT: Spec. Iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: The deep-ocean seafloor is an integral part of the ocean-atmosphere system. Processes occurring at and near the sediment-water interface can strongly influence chemical concentrations in the surface ocean (especially nutrients essential to primary production), the composition of the atmosphere (particularly its carbon dioxide content), and the record of past climate that is preserved in the sediments themselves. The importance of seafloor processes to our understanding of the ocean and the way chemicals cycle through it, past and present, has fostered many studies of this region, accounting for some 70 percent of the solid earth's surface. These investigations have detailed the origin, nature, and rate of material delivery to many areas of the seafloor. In addition, we have learned much about the reactions occurring on the seafloor and the profound influence they have on the fate of all materials delivered to this critical interface.
AN: 2837580

                                                                    905 of 1521  
TI: Introduction: Marine chemistry.
AU: Farrington,-J.W.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 11-17
NT: Spec. Iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: The oceans are a complex chemical soup. Marine chemists apply a variety of sophisticated instruments to defining the soup's chemical composition and the processes that control it, and to unravelling the biochemistry of the organisms that live in it. Their research advances general knowledge of the oceans and of chemistry, and frequently has immediate, profound implications for wise stewardship of local, regional, and global habitats.
AN: 2837549

                                                                    906 of 1521  
TI: Balancing the budget: Carbon dioxide sources and sinks, and the effects of industry.
AU: Takahashi,-T.; Tans,-P.P.; Fung,-I.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 18-28
NT: Spec. Iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: Molecules of carbon dioxide (CO sub(2)) and other trace gases absorb infrared radiation or heat. An atmospheric increase in these infrared-absorbing gases, which include water vapor, methane, and chlorofluorocarbon (the Freons or CFCs) would permit less heat to escape from Earth's surface into space. The atmosphere would retain more heat, in the way a greenhouse holds heat, and this "greenhouse effect" may be accompanied by some dire consequences: Regional desertification, dramatic sea-level rise, and an increase in both the frequency and intensity of hurricanes have been predicted. Greenhouse gases are measured regularly (from hourly to monthly, depending upon the intended purpose) all over the world, and chemical analyses of air bubbles trapped in old glacial ice provide pre-industrial concentrations. These measurements show that the atmospheric carbon dioxide concentration has increased by 25 percent since the pre-industrial period (1750 to 1800), from about 280 parts per million then to 350 parts per million by volume today. The concentration of methane has nearly doubled, from about 800 to 1,700 parts per billion since the pre-industrial time. The CFCs have gone from zero, prior to 1950, to about 600 parts per trillion today. Many observations support the notion that greenhouse warming is already occurring.
AN: 2837541

                                                                    907 of 1521  
TI: Sulphate-reduction and sulpho-oxidation at Cadiz Bay (S.W. Spain).
AU: Blasco,-J.; Gomez-Parra,-A.; Forja,-J.; Establier,-R.
AF: Inst. Cienc. Mar. de Andalucia, Poligono Rio San Pedro s/n, 11510 Puerto Real, Cadiz, Spain
SO: REV.-INT.-OCEANOGR.-MED. 1992. vol. 105-106, pp. 4-18
LA: English
ER: M (Marine)
AB: Sulphate reduction and sulpho-oxidation have been enzymatically determined in water and sediment from Cadiz Bay. The study has been performed during 1983-1984 in 12 sampling stations. They were selected taking into account both granulometry of the sediment and the different degree of influence of urban and industrial wastes. A significant positive correlation between sulphate reduction and sulpho-oxidation rates in sediments has been established, whereas only a relative seasonal evolution of sulpho-oxidation in the water column was found.
AN: 2835348

                                                                    908 of 1521  
TI: (Chemistry of aquatic environments. Chemistry of natural waters and interfaces in the environment.).
OT: Chimie des milieux aquatiques. Chimie des eau naturelles et des interfaces dans l'environnement
AU: Sigg,-L.; Stumm,-W.; Behra,-P.
AF: Ec. Polytech. Fed. Zurich (ETH, EAWAG)
SO: PARIS-FRANCE MASSON 1992. 391 pp
LA: French
ER: F (Freshwater)
AB: Chemistry of natural waters is a main bond between the great geochemical cycles and life on the planet. This chemistry, which reflects the mineral composition of the globe and the biochemical needs of the forms of life, is a central interest for environmental sciences. This book has been written for students and scientists studying waters--water cycles, water processes, water pollution, and air-water interaction--and for a class for the teaching of environmental chemistry and water chemistry, technology, geochemistry, and hydrobiology.
AN: 2835164

                                                                    909 of 1521  
TI: Geochemistry and loading history of phosphate and silicate in the Hudson Estuary.
AU: Clark,-J.F.; Simpson,-H.J.; Bopp,-R.F.; Deck,-B.
AF: Lamont-Doherty Geol. Obs., Columbia Univ., Palisades, NY 10964, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1992. vol. 34, no. 3, pp. 213-233
LA: English
ER: B (Brackish)
AB: The loading history and geochemistry of soluble reactive phosphorus (SRP) and dissolved silica (DSi) are evaluated in the Hudson estuary using 16 years of axial transect data. SRP behaves atypically in the estuary. Profiles show conservative mixing between a large mid-salinity source and the freshwater and seaward end members. Order of magnitude calculations indicate that waste water treatment facilities (WWTFs) are the dominant mid-salinity SRP source. DSi profiles display behaviour more typical of other estuaries in the northeastern United States, showing conservative mixing during periods of high flow and a midsalinity source during periods of low flow. A single layered multi-box model is used to evaluate the loading history of SRP and DSi.
AN: 2834889

                                                                    910 of 1521  
TI: The dynamic changes of stable isotopic ratios of carbon and nitrogen in suspended and sedimented particulate organic matter during a phytoplankton bloom.
AU: Nakatsuka,-T.; Handa,-N.; Wada,-E.; Wong,-Chi-Shing
AF: Water Res. Inst., Nagoya Univ., Chikusa-ku, Nagoya 464-01, Japan
SO: J.-MAR.-RES. 1992. vol. 50, no. 2, pp. 267-296
LA: English
ER: M (Marine)
AB: The dynamic changes of carbon and nitrogen stable isotopic ratios in suspended and sedimented particulate matter were observed together with many other chemical and biological properties during a phytoplankton bloom induced by nutrient addition in a controlled ecosystem enclosure (CEE, about 70 m super(3)) in Saanich Inlet, British Columbia, Canada. Both of the stable isotopic ratios of carbon ( delta  super(13)C) and nitrogen ( delta  super(15)N) in suspended particulate organic matter showed characteristic patterns of variations in surface water during the bloom. The  delta  super(13)C of suspended particulate matter increased with the growth of phytoplankton population and decreased gradually after the depletion of NO sub(3) super(-) and NO sub(2) super(-). The  delta  super(15)N of suspended particulate matter was very low soon after the beginning of phytoplankton bloom, but the value increased rapidly with the decrease in NO sub(3) super(-) and NO sub(2) super(-), and reached maximal value following nutrient depletion, after which the  delta  super(15)N remained high until the end of the experiment.
AN: 2833217

                                                                    911 of 1521  
TI: (Fate and effects of trace elements in marine organisms.).
OT: Devenir et effets des elements traces dans les organismes marins
AU: Romeo,-M.; Amiard,-J.C.
AF: INSERM, 4303 "Mer et Sante", B.P. 3, 06230 Villefranche-sur-mer, France
SO: ANALUSIS. 1992. vol. 20, no. 6, pp. M42-M44
LA: French
ER: M (Marine)
AB: By their bioaccumulation capacity and their secretion marine organisms play an important part in the biogeochemical cycles of metals in marine environment. By the possible bioaccumulation at different levels of the food chain these trace elements can be dangerous for human health.
AN: 2832627

                                                                    912 of 1521  
TI: Modification of the N:P ratio in lakes by in situ processes.
AU: Levine,-S.N.; Schindler,-D.W.
AF: Sch. Nat. Resour., Univ. Vermont, Burlington, VT 05405, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 5, pp. 917-935
LA: English
ER: F (Freshwater)
AB: In situ mesocosms in two Canadian Shield lakes were used to evaluate the contributions of in-lake vs. external sources of nitrogen and phosphorus to nutrient budgets and N:P ratios. These mesocosms were designed to have variable exchange with sediments. Half were fertilized with N and P at a ratio great enough to ensure P limitation for most phytoplankton (atomic ratio, 33:1); the other half were fertilized at a ratio low enough to cause N limitation (4.4:1) in the absence of compensation mechanisms. For littoral mesocosms, sediments were a major source of N, but not of P. A comparison of mesocosms having sediments with one having a plastic floor indicated that sediment N return was derived largely from decomposing material at the sediment surface, rather than from deep sediments. Disproportionate returns of N from sediments, along with lower denitrification, reduced N limitation in the low N:P mesocosms. In pelagic mesocosms, which lacked sediment contact, N sub(2) fixation and thermocline entrainment late in the experiment were the principal internal N sources at low N:P.
AN: 2831166

                                                                    913 of 1521  
TI: Benthic boundary layer communities and carbon cycling at abyssal depths in the Central North Pacific.
AU: Smith,-K.L.,Jr.
AF: Mar. Biol. Res. Div., 0202, Scripps Inst. Oceanogr., UCSD, La Jolla, CA 92093-0202, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 5, pp. 1034-1056
LA: English
ER: M (Marine)
AB: Cycling of carbon through the benthic boundary layer (BBL) community in the deep sea is poorly understood. Until now, attempts to summarize the flow of organic C in these communities have relied primarily on data collected from various deep-sea areas. The one BBL community where the organic C pools and fluxes are best defined is in the central North Pacific, north of the Hawaiian Islands. This data base was combined with new estimates of standing stocks and organic C fluxes to construct an organic C budget for the bottom 600 m of the water column and the sediments, using net input from sinking particulate organic C (POC) and exchanges between 12 compartments. The largest standing stocks of C (dissolved organic C, suspended POC, and POC) were in the water and surface sediments (9.1 x 10 super(8) g C km super(-2)), exceeding that in the 10 consumer groups by almost four orders of magnitude. Of the consumer groups, the sediment nanobiota, meiofauna, and epibenthic megafauna had the most organic C and the macrofauna had the least. Fluxes into the consumer groups, as estimated from respiration rates, were highest in the sediment community, bacterioplankton, and epibenthic megafauna.
AN: 2830941

                                                                    914 of 1521  
TI: The nitrogen:phosphorus relationship in lakes.
AU: Downing,-J.A.; McCauley,-E.
AF: Dep. Sci. Biol., Univ. Montreal, C.P. 6128, Succursale A, Montreal, Que. H3C 3J7, Canada
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 5, pp. 936-945
LA: English
ER: F (Freshwater)
AB: Published data on mean annual epilimnetic total N (TN) and P (TP) were analyzed to find how TN:TP varies with lake trophic status. TN:TP is high in oligotrophic lakes and very low in eutrophic lakes, declining in a curvilinear fashion with increased TP. Comparison of this trend with published N:P in lake nutrient sources suggests that TN:TP reflects the source of nutrients: the ratio is high in oligotrophic lakes because they receive their N and P from natural, undisturbed watersheds which export much less P than N; mesotrophic and eutrophic lakes receive various mixtures of nutrient sources that have lower average N:P; and very eutrophic lakes have N:P that correspond very nearly to the N:P of sewage. Two inflection points were identified in the TN:TP relationship ( similar to 20 and  similar to 100  mu g TP/liter) the first probably reflecting the large difference between TN:TP in nutrient export from undisturbed terrestrial ecosystems and that of meso- and eutrophic sources such as urban and pasture land runoff and sewage, and the second probably reflecting increased rates of denitrification in eutrophic lakes.
AN: 2830754

                                                                    915 of 1521  
TI: Epilithic extracellular enzyme activity in acid and calcareous headstreams.
AU: Chappell,-K.R.; Goulder,-R.
AF: Dep. Appl. Biol., Univ. Hull, Hull HU6 7RX, UK
SO: ARCH.-HYDROBIOL. 1992. vol. 125, no. 2, pp. 129-148
NT: Bibliogr.: 40 ref.
LA: English
ER: F (Freshwater)
AB: Extracellular enzyme activity of intact epilithon on small stones from headstreams was assayed using 4-methylumbelliferyl substrates. The stones were collected from seven calcareous streams and eight, sometimes acid, streams on millstone grit in N England. Epilithic glycosidase ( beta -D-glucosidase,  beta -D-galactosidase,  beta -D-xylosidase) and sulphatase activity was greater in the calcareous streams but phosphatase activity was greater in the millstone-grit streams. In most streams the activity of phosphatase >  beta -D-glucosidase >  beta -D-galactosidase,  beta -D-xylosidase and sulphatase. Correlation coefficients and multiple-regression analysis suggested the epilithic enzyme activities were potentially controlled by water quality variables (pH, temperature, conductivity, A sub(320)) and epilithic microbial variables (bacterial activity, total bacteria, chlorophyll-a) but not by variables which described stone character and location (stone size, water velocity and depth).
AN: 2829872

                                                                    916 of 1521  
TI: Effects of increasing levels of CO sub(2) and O sub(2) derived compounds on biogeochemical cycles and shaping of the biosphere.
AU: Penuelas,-J.
AF: Inst. Rec. y Tecnol. Agroaliment., Cent. Cabrils, Crtra. de Cabrils, s/n. 08348 Barcelona, Spain
SO: HOMAGE-TO-RAMON-MARGALEF;-OR,-WHY-THERE-IS-SUCH-PLEASURE-IN-STUDYING-NATURE. Ros,-J.;Prat,-N.-eds. BARCELONA-SPAIN UNIV.-DE-BARCELONA 1992. no. 10 pp. 367-385
ST: OECOL.-AQUAT.-SPEC.-ISS.. no. 10
LA: English
ER: B (Brackish)
AB: Plants reduce CO sub(2) to molecular species of increasing energy content. These compounds are then moved by heterotrophic organisms through decreasing energy levels as the organic matter is returned to inorganic form by successive oxidations. Thus, CO sub(2) and O sub(2) are the major substrates of biospheric reactions. Oxygen is toxic for anaerobic and, in excess, for aerobic organisms. Its toxicity is overcome by aerobic organisms by using it as an electron terminal acceptor in respiration and by developing biochemical defenses. It still determines phenomena such as anaerobiosis, the depth limit of higher aquatic plants, or bioluminescence, and perhaps others like the diurnal vertical migration of zooplankton. Low photosynthetic efficiency in light use, shape and color of vegetation may result from the peculiar availability of light and CO sub(2).
AN: 2829838

                                                                    917 of 1521  
TI: Methane metabolism in Baltic lakes of different trophic state.
OT: Methanhaushalt in baltischen Seen unterschiedlicher Trophiestufe
AU: Casper,-P.
AF: Inst. Gewaesseroekol. und Binnenfisch. Berlin e.V., Abt. Limnol., Alte Fischerhuette 2, D-O 1431 Neuglobsow, FRG
SO: LIMNOLOGICA. 1992. vol. 22, no. 2, pp. 121-128
NT: Bibliogr.: 30 ref.
LA: German
ER: F (Freshwater)
AB: Methane concentrations in different depths of the pelagic water columns and of sediment cores were examined in five lakes of the Lake Stechlin are and the Feldberg Lakes area. Measurements were carried out at the beginning of summer stagnation and of fall turnover. The highest methane concentrations were found near the sediment surface at the beginning of the stagnation period. The concentrations ranged from 0.1-10  mu mol/l in the water columns of the investigated oligotrophic and acidotrophic lakes to 10-100  mu mol/l in both eutrophic lakes. Methane production occurs in Lake Stechlin and Lake Fuchskuhle mainly below 15-20 cm sediment. In the eutrophic lakes methane is produced in the upper zone of sediments (0-3 cm) and during circulation in deeper zones (below 5 cm). The concentration of methane in the interstitial water reached in all investigated lakes below 5-10 cm sediment saturation levels (more than 1000  mu mol/l).
AN: 2826769

                                                                    918 of 1521  
TI: A device for in situ determination of geochemical transport parameters. 2. Biochemical reactions.
AU: Gillham,-R.W.; Starr,-R.C.; Miller,-D.J.
AF: Waterloo Cent. Groundwater Res., Dep. Earth Sci., Univ. Waterloo, Waterloo, ON N2L 3G1, Canada
SO: GROUND-WATER. 1990. vol. 28, no. 6, pp. 858-862
LA: English
ER: F (Freshwater)
AB: Chemical and biological reaction rates are required in estimating migration rates of many reactive contaminants in ground water, and as input data for mathematical models. Reaction rates must be measured, and depend on environmental conditions that are often difficult to duplicate in the laboratory. In situ rate measurement minimizes the difficulties of controlling environmental variables such as temperature, pH, Eh, DO, solution and solid phase composition, and bacterial population. The instrument described in this paper isolates a 1.9 liter portion of an aquifer for in situ biochemical rate measurement. The device has been used successfully to measure the rate of reactions involving inorganic and organic contaminants in sandy aquifers. Two applications of the device, measurement of denitrification rates and rates of biodegradation of benzene, are presented.
AN: 2824590

                                                                    919 of 1521  
TI: An advection/diffusion model for  super(222)Rn transport in near-shore sediments inhabited by sedentary polychaetes.
AU: Benoit,-J.M.; Torgersen,-T.; O'-Donnell,-J.
AF: Dep. Mar. Sci., Univ. Connecticut, Groton, CT 06340, USA
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 105, no. 4, pp. 463-473
LA: English
ER: M (Marine)
AB: A porewater solute transport model is proposed to explain the dissolved radon distributions in four profiles from a near-shore, marine site. The macro-infauna at the site is dominated by Clymenella torquata , a sedentary deposit feeding polychaete that actively irrigates its burrow. The model includes both an advective component that takes into account the (e.g.) C. torquata  mechanism of burrow irrigation as well as enhanced diffusion-like transport brought about by mobile infauna. Because it explains the existence of subsurface radon minima with a constant source function and is based on the known irrigation habits of C. torquata , the model provides good fit to observed radon profiles and may be applicable to other solutes that display depth dependent minima.
AN: 2824414

                                                                    920 of 1521  
TI: Comparison of selenomethionine and selenite cycling in freshwater experimental ponds.
AU: Graham,-R.V.; Blaylock,-B.G.; Hoffman,-F.O.; Frank,-M.L.
AF: Environ. Sci. Div., Oak Ridge Natl. Lab., Oak Ridge, TN 37831-6036, USA
SO: WATER-AIR-SOIL-POLLUT. 1992. vol. 62, no. 1-2, pp. 25-42
LA: English
ER: F (Freshwater)
AB: A comparison of the cycling and fate of  super(75)Se in an aquatic ecosystem was investigated when selenite or selenomethionine was introduced as an acute release into two experimental ponds. Biotic and abiotic compartments were periodically sampled to measure  super(75)Se concentrations throughout the 318-d experiment. The biotic compartments were periphyton, rooted pondweed (Elodea canadensis ), snails (Helisoma  sp.), and mosquitofish (Gambusia affinis ). Results show that the uptake rates in the biotic compartments for  super(75)Se-selenomethionine were at least an order of magnitude greater than for  super(75)Se-selenite. However, elimination rates for respective biotic compartments were similar. Seasonal sediment  super(75)Se concentrations in both ponds decreased simultaneously with increases in  super(75)Se concentrations within biotic compartments. This suggests that sediment is a secondary source of  super(75)Se rather than a sink in some shallow freshwater systems.
AN: 2823857

                                                                    921 of 1521  
TI: Detrital pathways in a coral reef lagoon. 2. Detritus deposition, benthic microbial biomass and production.
AU: Hansen,-J.A.; Klumpp,-D.W.; Alongi,-D.M.; Dayton,-P.K.; Riddle,-M.J.
AF: Australian Inst. Mar. Sci., P.M.B. No. 3, Townsville M.C., Qld. 4810, Australia
SO: MAR.-BIOL. 1992. vol. 113, no. 3, pp. 363-372
NT: Bibliogr.: 39 ref.
LA: English
ER: M (Marine)
AB: We report the results of seasonal measurements, taken in 1986, of bacterial numbers and production, protozoan numbers, community primary production and respiration in the sediments of Davies Reef lagoon. Deposition rates of organic matter in the lagoon were also measured. Deposition rates ( plus or minus 1 SE) of carbon ranged from 9.2 ( plus or minus 1.5) to 140.7 ( plus or minus 10.3) mgCm super(-2)/d. Deposition rates were highest in winter and spring, lowest in summer. Rates of bacterial production ranged from 4.7 ( plus or minus 0.2) pmol thymidine incorporated/g dry wt (DW)/h in winter to 23.5 ( plus or minus 1.0) pmol thymidine incorporated/g DW/h in spring. The number of ciliates ranged from 65 ( plus or minus 10) to 356 ( plus or minus 50) cm super(-3) through the year and the number of large ( greater than or equal to 20  mu m) flagellates from 38 ( plus or minus 7) to 108 ( plus or minus 16) cm super(-3). There were no clear relationships between the sediment organic content, detrital input or temperature and the rates of bacterial processes, community metabolism or the standing stocks of microbes in the lagoon.
AN: 2823831

                                                                    922 of 1521  
TI: Interaction between dissolved organic matter in seawater and copper.
AU: Midorikawa,-T.; Tanoue,-E.; Sugimura,-Y.
AF: Geochem. Lab., Meteorol. Res. Inst., Nagamine 1-1, Tsukuba, Ibaraki 305, Japan
CO: 5. Int. Meet. of the Humic Substances Soc., Nagoya (Japan), 6-10 Aug 1990
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 117-118, pp. 499-507
LA: English
ER: M (Marine)
AB: Dissolved organic matter in coastal seawater was investigated in terms of the interaction with copper. Three classes of organic ligands were distinguished from each other by differences in their complexing abilities for copper. Two ligands were determined by copper titration, using an ion selective electrode. Another ligand was detected by the competitive reaction for copper with an excess amount of EDTA. It was found that the third ligand was stronger than two ligands characterized by the copper titration method. The occurrence of a ligand having a high affinity for copper suggests the possible importance of organic ligands on the geochemical cycle of copper in the ocean.
AN: 2821371

                                                                    923 of 1521  
TI: Impact of oceanic sources of biogenic sulphur on sulphate aerosol concentrations at Mawson, Antarctica.
AU: Prospero,-J.M.; Savoie,-D.L.; Saltzman,-E.S.; Larsen,-R.
AF: Univ. Miami, RSMAS/MAC, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: NATURE. 1991. vol. 350, no. 6315, pp. 221-223
LA: English
ER: M (Marine)
AB: Sulphate is the dominant aerosol species in the Antarctic atmosphere and an important constituent in Antarctic snow and ice. Various sources have been suggested for Antarctic non-sea-salt sulphate (n.s.s. SO sub(4)@) super(2)-:) volcanic emissions, stratospheric injection, pollutants transported from the low latitudes and biogenic dimethylsulphide (DMS) from the ocean. Although the oceanic source is now believed to be especially important, there has been no strong chemical evidence directly linking oceanic DMS with the Antarctic n.s.s. SO sub(4)@) super(2)-c)oncentrations. Here we present extended measurements from the Antarctic for both n.s.s. SO sub(4)@) super(2)-a)nd methanesulphonate (MSA), an oxidation product of DMS. Both species have a very strong seasonal cycle with a maximum in the austral summer.
AN: 2821245

                                                                    924 of 1521  
TI: Effects of forest herbicide applications on streamwater chemistry in southwestern British Columbia.
AU: Feller,-M.C.
AF: Fac. For., Univ. British Columbia, Vancouver, B.C. V6T 1W5, Canada
SO: WATER-RESOUR.-BULL. 1989. vol. 25, no. 3, pp. 607-616
LA: English
ER: F (Freshwater)
AB: The herbicide glyphosate was applied to portions of two watersheds in southwestern British Columbia to kill vegetation that was competing with Pseudotsuga menziesii  (Douglas-fir) plantations. This application had little significant effect on streamwater chemistry when vegetation cover in a watershed was reduced by 4%, but has significant effects, which lasted for at least five years, when cover was reduced by 43%. In this case, most parameters increased in value following the application. In watersheds similar to those of the study area, herbicide application is likely to have a greater impact on streamwater chemistry, in general, than would clearcutting or clearcutting followed by slashburning.
AN: 2820367

                                                                    925 of 1521  
TI: Impact of atmospheric deposition on particulate manganese and aluminium distribution in northwestern Mediterranean surface water.
AU: Davies,-J.E.; Buat-Menard,-P.
AF: Cent. Faibles Radioact., Lab. Mixte CNRS-CEA, Domaine CNRS, F-91198 Gif-sur Yvette Cedex, France
SO: PALAEOGEOGR.,-PALAEOCLIMATOL.,-PALAEOECOL. 1990. vol. 89, no. 1-2, pp. 35-45
LA: English
ER: M (Marine)
AB: Sediment-trap samples and upper-water-column profiles of suspended particulate matter were collected at 42 degree 44'N, 8 degree 31'E in the northwestern Mediterranean Sea during 1987 as part of the French DYFAMED programme. Particulate sediment-trap samples and suspended particulate matter were analysed for aluminium and manganese. In specified samples, fecal-pellet fluxes were also measured. Concurrent manganese and aluminium atmospheric-depositional fluxes measured at Capo Cavallo, Corsica, 20 km from our sampling site were available for the corresponding sampling period for data interpretation. The results show that on a yearly basis the atmospheric input (1.6 mg Al/m super(2)/day and 30.6  mu g Mn/m super(2)/day) is sufficient to be the major source of both particulate aluminium and particulate (LE(leachable) + RE(refractory)) manganese in the sediment-trap flux at a depth of 200 m (2.2 mg Al/m super(2)/day and 22.5  mu g Mn/m super(2)/day). Significant correlation between both particulate-aluminium and refractory-particulate-manganese fluxes and the fecal-pellet fluxes shown that the settling flux of atmosphere mineral matter is probably governed by zooplankton grazing.
AN: 2819134

                                                                    926 of 1521  
TI: Modelling the biogenic transport of atmospheric particles in the Mediterranean Sea.
AU: Ruiz-Pino,-D.P.; Lambert,-C.E.; Jeandel,-C.; Buat-Menard,-P.
AF: Lab. Phys. et Chim. Mar., Univ. Paris 6, UA CNRS, B.P. 8, F-06230 Villefranche-sur-mer, France
SO: PALAEOGEOGR.,-PALAEOCLIMATOL.,-PALAEOECOL. 1990. vol. 89, no. 1-2, pp. 47-64
LA: English
ER: M (Marine)
AB: To help the assessment of the geochemical impact of sporadic events such as Saharan dust storms on the biogeochemical cycles of trace elements in the Mediterranean Sea, a one-dimensional multilayered model of the transport of atmospheric particles in the water column was developed. The model used data of the DYFAMED programme. Particulate aluminium was taken as a tracer of mineral particles. The Al atmospheric-source function was based on time-series data obtained at a coastal station in the Ligurian Sea. The response time throughout the water column was modulated by zooplankton grazing and water stratification. Stratification varies during the course of the year and induces variations of the eddy diffusivity coefficients which were calculated for the surface and deep layers. Runs of the model over one year displayed strong seasonal variations in particulate aluminium concentration and flux which agree with experimental data. Temporal changes of the particulate flux out of the euphotic zone are also clearly affected by the intensity and duration of the dust storm. The highest values of particulate flux occur as a consequence of the removal of dust particles from the surface layer when biological activity is high.
AN: 2819003

                                                                    927 of 1521  
TI: Recent improvements of ammonium and total phosphorus analysis in sea water.
AU: Degobbis,-D.; Ivancic,-I.
AF: "Ruder Boskovic" Inst., Cent. Mar. Res., 52210 Rovinj, Yugoslavia
SO: OEBALIA. 1991. vol. 17,N.S., pp. 221-235
LA: English
ER: M (Marine)
AB: Recent efforts to improve the analytical methods for ammonium and total phosphorus determinations in seawater are briefly reviewed. Some notes on seawater sample storage and treatment are also given.
AN: 2815434

                                                                    928 of 1521  
TI: The importance of denitrification.
OT: Typenpoiston tarpeellisuudesta
AU: Seppaenen,-H.
SO: VESITALOUS. 1992. vol. 33, no. 1, pp. 6-11
LA: Finnish
AN: 2814459

                                                                    929 of 1521  
TI: Deposit feeding and sediment: 2. Decomposition of fecal pellets of Holothuria tubulosa  (Holothurioida, Echinodermata).
AU: Amon,-R.M.W.; Herndl,-G.J.
AF: Univ. Texas at Austin, Mar. Sci. Inst., P.O. Box 1267, Port Aransas, TX 78373, USA
SO: P.S.Z.N.-I:-MAR.-ECOL. 1991. vol. 12, no. 2, pp. 175-184
LA: English
ER: M (Marine)
AB: The effect of defecation and decomposition of fecal pellets egested by the deposit feeding Holothuria tubulosa  on the microbial productivity of sediments was investigated in microcosm experiments. H. tubulosa  specimens were collected from a 5 m deep seagrass meadow in the nearshore waters of the Mediterranean Sea off Lacco Ameno (Island of Ischia, Gulf of Naples, Italy). Experiments were performed under different temperature regimes. Bacterial production in the incubation media and within fecal pellets increased with increasing temperature. Incubation experiments on the effect of feces on natural sediments indicated that fecal pellet production by H. tubulosa  enhanced sediment bacterial production by about 30%. Two independent methods were used to estimate leaching of dissolved carbohydrates from fecal pellets. One method was based on the increase in total dissolved carbohydrates in the incubation medium, the other on the decrease in total particulate carbohydrates of the fecal matter.
AN: 2813482

                                                                    930 of 1521  
TI: Deposit feeding and sediment: 1. Interrelationship between Holothuria tubulosa  (Holothurioida, Echinodermata) and the sediment microbial community.
AU: Amon,-R.M.W.; Herndl,-G.J.
AF: Univ. Texas at Austin, Mar. Sci. Inst., P.O. Box 1267, Port Aransas, TX 78373, USA
SO: P.S.Z.N.-I:-MAR.-ECOL. 1991. vol. 12, no. 2, pp. 163-174
LA: English
ER: M (Marine)
AB: The feeding of the epibenthic deposit-feeder Holothuria tubulosa  and its influence on sediment metabolism was investigated from February 1988 to February 1989. Water samples, specimens of H. tubulosa , and samples of freshly egested feces were taken by SCUBA diving in a 5 m deep seagrass bed at the Island of Ischia in the Gulf of Naples (Italy). Particulate organic carbon (POC), particulate organic nitrogen (PON), total particulate carbohydrates (PCHO), and bacterial biomass exhibited higher values in the foregut than in the surrounding sediment. Even the freshly egested feces were richer in the organic components than the sediment. The percentage of growing bacterial cells increased from 4.1% in the sediment to 12.2% in the foregut and declined to 11.6% in the hindgut and 6.2% in freshly egested feces.
AN: 2813469

                                                                    931 of 1521  
TI: The detritic compartment in a Posidonia oceanica  meadow: Litter features, decomposition rates, and mineral stocks.
AU: Romero,-J.; Pergent,-G.; Pergent-Martini,-C.; Mateo,-M.-A.; Regnier,-C.
AF: Dep. Ecol., Univ. Barcelona, Diagonal 645, E-08028 Barcelona, Spain
SO: P.S.Z.N.-I:-MAR.-ECOL. 1992. vol. 13, no. 1, pp. 69-83
LA: English
ER: M (Marine)
AB: The ecosystem associated to the Mediterranean seagrass Posidonia oceanica  shows a clear distinction in two subcompartments regarding turnover time: aboveground and belowground. Aboveground parts (leaves) are highly dynamic, and most of the leaf material is decomposed or exported in less than one year, representing a net loss of nutrients. In contrast, belowground biomass (roots and rhizomes) has a turnover time of the order of centuries, with a consequent accumulation of organic matter in the sediment. The accumulation rates for the single elements rank in the order C > N > P. This ecosystem may be considered as a sink for biogenic elements.
AN: 2813318

                                                                    932 of 1521  
TI: Early diagenesis of organic matter in the water column and sediment in a eutropic lake: Lake of Aydat (Puy-de-Dome, France).
OT: Diagenese precoce de la matiere organique dans la colonne d'eau et le sediment d'un lac eutrophe: Le lac d'Aydat (Puy-de-Dome)
AU: Sarazin,-G.; Devaux,-J.
AF: Univ. Paris VII, Lab. Geochim. Eaux, 75251 Paris Cedex 05, France
CO: Les Lacs comme Modele d'Ocean, Paris (France), 23 Nov 1990
SO: LAKES-AS-OCEAN-MODELS,-23-NOVEMBER-1990.  LES-LACS-COMME-MODELE-D'-OCEAN,-23-NOVEMBRE-1990. Pourriot,-R.-ed. 1991. vol. 17, no. 5 pp. 533-560
ST: OCEANIS-DOC.-OCEANOGR.. vol. 17, no. 5
LA: French
ER: M (Marine)
AB: The acquisition of a large number of data concerning the water column and the sediment pore water of a eutrophic lake (Lake of Aydat, Puy-de-Dome, France) enabled us to determine the main biogeochemical processes responsible for the mineralization of organic matter produced within the lacustrine ecosystem. In the oxygenated epilimnion, during the summer stratification period, direct oxidation with oxygen prevails. Within the anoxic hypolimnion the main oxidants are particulate and insoluble ferric and manganic compounds; at the same time the disproportionation of organic matter releases equivalent amounts of CO sub(2) and CH sub(4) via bacteria. With the exception of oxygen, the same electron acceptors are found in the pore water medium. Stoichiometric modeling provides us with a global formula for organic matter undergoing these reactions. The C:N ratio is nearly identical to that of Redfield, while the difference observed in the C:P ratio is explained by a close coupling of the chemistries of iron and phosphorus.
AN: 2813028

                                                                    933 of 1521  
TI: Sulfur: The plankton/climate connection.
AU: Malin,-G.; Turner,-S.M.; Liss,-P.S.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: J.-PHYCOL. 1992. vol. 28, no. 5, pp. 590-597
LA: English
ER: M (Marine)
AB: A key process in the global sulfur cycle is the transfer of volatile forms of the element from sea to land via the atmosphere. Early budgets calculated the amount of sulfur required to balance the cycle and generally assumed that this flux was achieved by formation of hydrogen sulfide (H sub(2)S) in coastal waters, mud flats, etc. However, Lovelock et al. (1972) made the first field measurements of dimethylsulfide (DMS) in seawater and suggested that it represented the missing link in the S cycle. In this review we consider processes leading to the formation of DMS in seawater, its emission to the atmosphere, and transformation therein, the possible role of DMS oxidation products in climate regulation as proposed by Charlson et al. (1987), and how global changes might affect DMS production.
AN: 2812490

                                                                    934 of 1521  
TI: Remote sensing of oceanic biology in relation to global climate change.
AU: Aiken,-J.; Moore,-G.F.; Holligan,-P.M.
AF: Nat. Environ. Res. Counc., Plymouth Mar. Lab., Prospect Pl., West Hoe, Plymouth PL1 3DH, UK
SO: J.-PHYCOL. 1992. vol. 28, no. 5, pp. 579-590
LA: English
ER: M (Marine)
AB: This review of the remote sensing of oceanic phytoplankton has indicated how the CZCS, despite instrumental limitations of spectral resolution and sensitivity, has produced a wealth of new information on biomass distributions and provided the basis for new approaches to the estimation of global marine primary productivity. Simulations of new ocean color sensors such as SeaWiFS, based on aircraft multispectral data, indicate a significant improvement in performance and accuracy compared to the CZCS, with only a modest change in specification in terms of the addition of sensor channels in the infrared for atmospheric corrections and visible bands for better pigment estimates.
AN: 2812477

                                                                    935 of 1521  
TI: Landscape properties of pocosins and associated wetlands.
AU: Brinson,-M.M.
AF: Dep. Biol., East Carolina Univ., Greenville, NC 27858, USA
SO: WETLANDS. 1991. vol. 11, no. Sp. Iss., pp. 441-466
NT: Spec. Iss.: Advanced identification in Pocosins.
LA: English
ER: F (Freshwater)
AB: Most pocosins occur on broad, relatively flat interfluves or near estuaries where rising sea level affects their hydrology. Traditionally accepted ecological functions are low when compared on a unit area basis with other wetland types. An understanding of the interaction of pocosins with the atmosphere is fundamental to revealing mechanisms for their formation and their importance in landscape-level biogeochemical processes such as producing and consuming greenhouse gases and receiving and processing acid deposition. At least four interactions between pocosins and estuaries are important at landscape scales: maintaining landscape elevation in the context of rising sea level, representing a platform upon which landward migrating brackish marshes can develop, exporting high concentrations of organic carbon, and influencing the quality of habitat in primary nursery areas for fish and shellfish. Since pocosins have lower rates of cycling for most elements, greater surface area of pocosin is required to provide the same function and life support as floodplain wetlands.
AN: 2812163

                                                                    936 of 1521  
TI: Chemical, isotopic, spectroscopic and geochemical aspects of natural and synthetic humic substances.
AU: Ikan,-R.; Ioselis,-P.; Rubinsztain,-Y.; Aizenshtat,-Z.; Miloslavsky,-I.; Yariv,-S.; Pugmire,-R.; Anderson,-L.L.; Woolfenden,-W.R.; et-al.
AF: Dep. Org. Chem., Hebrew Univ., Jerusalem, Israel
CO: 5. Int. Meet. of the Humic Substances Soc., Nagoya (Japan), 6-10 Aug 1990
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 117-118, pp. 1-12
LA: English
ER: M (Marine)
AB: It has been suggested that marine humic and fulvic acids are formed by a condensation of sugars with amino acids or proteins via Maillard reaction. In order to investigate this hypothesis a series of melanoidins were synthesised under laboratory conditions and their structure compared with natural humic acids. An extensive collaborative research programme on the chemical and physical properties of natural and synthetic humic substances has been undertaken using spectroscopic, chromatographic, thermogravimetric, pyrolytic oxidative and isotopic methods. The results indicate that various heterocyclic moieties are the main building blocks of humic substances rather than aromatic benzenoid structures.
AN: 2811759

                                                                    937 of 1521  
TI: Pacific CaCO sub(3) preservation and  delta  super(18)O since 4 Ma: Paleoceanic and paleoclimatic implications.
AU: Farrell,-J.W.; Prell,-W.L.
AF: Dep. Geol. Sci., Brown Univ., Providence, RI, USA
SO: PALEOCEANOGRAPHY. 1991. vol. 6, no. 4, pp. 485-498
LA: English
ER: M (Marine)
AB: The Pliocene-Pleistocene history of CaCO sub(3) preservation in the central equatorial Pacific is reconstructed from a suite of deep-sea cores and is compared to fluctuations in global ice volume inferred from  delta  super(18)O records. The results are highlighted by: (1) strong covariation between CaCO sub(3) preservation and ice volume over 10 super(4) to 10 super(6) year time scales; (2) a long-term increase in ice volume and CaCO sub(3) preservation since 3.9 Ma demonstrated by a deepening of the lysocline and the carbonate critical depth; (3) a dramatic shift to greater CaCO sub(3) preservation at 2.9 Ma; (4) distinctive ice-volume growth and CaCO sub(3) preservation events at 2.4 Ma, which are associated with the significant intensification of northern hemisphere glaciation; (5) a mid-Pleistocene transition to 100-kyr cyclicity in both CaCO sub(3) preservation and ice volume; and (6) a 600-kyr Brunhes dissolution cycle superimposed on the late Pleistocene glacial/interglacial 100-kyr cycles. CaCO sub(3) preservation primarily reflects the carbonate chemistry of abyssal waters and is controlled by long-term (10 super(6) year) and short-term (10 super(4) to 10 super(5) year) biogeochemical cycling and by distinct paleoclimatic events.
AN: 2811192

                                                                    938 of 1521  
TI: In situ studies on transformation of organic matter by Mytilus galloprovincialis .
AU: Baudinet,-D.; Grenz,-C.; Masse,-H.
AF: Inst. Maurice Lamontagne, Mont-Joli, Canada
CO: Aquaculture '92, Orlando, FL (USA), 21-25 May 1992
SO: AQUACULTURE-'-92:-GROWING-TOWARD-THE-21st-CENTURY. 1992. p. 37
NT: Summary only.
LA: English
ER: M (Marine)
AB: In situ multiparameter studies were driven for three years in a Mediterranean shellfish farming ecosystem to observe direct and indirect transformations of organic matter by a benthic filter feeder, Mytilus galloprovincialis . Chemical parameters measured in the water column and at the sediment-water interface from a reference station (without mussels) and another one located in a mussel rope hanging structure (a mussel table), are compared. One mussel production unit modifies an equivalent volume of water by a significant transformation of particulate and dissolved matter: 40% of the available potential energy contained in particulate organic matter, 21% of the particulate carbon and particulate nitrogen, 70% of the dissolved free amino acids were removed; phaeopigments (40%), as well as ammonia (84%) and urea (25%) are increased. The ammonia released by excretion is 37 times higher than provided by biodeposit mineralisation. From these results, a nitrogen budget for a mussel production unit is proposed.
AN: 2810102

                                                                    939 of 1521  
TI: Bioturbation by Nereis  sp. and its effects on the phosphate flux across the sediment-water interface in the Palmones River estuary.
AU: Clavero,-V.; Fernandez,-J.A.; Niell,-F.X.
AF: Dep. Ecol., Fac. Sci., Malaga Univ., 29071 Malaga, Spain
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 387-392
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: M (Marine); B (Brackish)
AB: The effects of Nereis  sp. on the flux of dissolved phosphate across the sediment-water interface has been studied in Palmones River estuary using benthic flux-chambers and intact cores. Diffusive fluxes of phosphate were calculated from pore water gradient concentration and compared with those obtained from benthic chambers experiments. The high abundance of Nereis  in the upper sediment layers appears to play an important part in the dissolved oxygen profiles in the overlying water, but had no effect on the redox potential. A negative relationship was found between the Nereis  abundance and the phosphate gradient; this gradient ranged between 40  mu mol/l/cm with 340 Nereis  individuals m super(-2) and 20  mu mol/l/cm with 900 Nereis  individuals m super(-2). The ratio of the in situ flux to the flux gradient concentration for dissolved phosphate increased with the abundance of Nereis  (from 1.7 at low abundance to 5.8 at high abundance).
AN: 2805873

                                                                    940 of 1521  
TI: Sediment/water interactions.
AU: Hart,-B.T.; Sly,-P.G.-(eds.)
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: HYDROBIOLOGIA. 1992. vol. 235-236, 743 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The Fifth Symposium on Sediment/Water Interactions was held in Uppsala, Sweden, 6-9 August, 1990. As in previous proceedings, the preface has been used to highlight scientific advances and the significance of particular contributions. The papers appearing in this issue of Hydrobiologia reflect the current attention in sediment/water science to five main topics of investigation: Sediment dynamics in estuaries, coastal waters, lakes, reservoirs and rivers; Sediment-associated biological processes; Contaminant accumulation, distribution and geochemistry; Fluxes from sediments; and Element cycling.
AN: 2805371

                                                                    941 of 1521  
TI: Sulphur isotope ratios in sulphate and oxygen isotopes in water from a small watershed in central Sweden.
AU: Andersson,-P.; Torssander,-P.; Ingri,-J.
AF: Div. Geol. and Planet. Sci., California Inst. Technol., Pasadena, CA 91125, USA
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 205-217
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: F (Freshwater)
AB: During 1988-89 water samples for sulphur and oxygen isotope measurements were collected in the Lake Mjoesjoen watershed (7.3 km super(2)), central Sweden. Samples included: precipitation, throughfall, lakewater, shallow groundwater and inlet and outlet streams. The  delta  super(34)S of sulphate in precipitation ranged from + 6.41 ppt in winter to + 3.88 ppt in summer, the higher winter values attributed to seasonal differences in the kinetic and equilibrium isotope fractionation during oxidation of atmospheric sulphur dioxide to sulphate. The  delta  super(34)S in rain samples and in pine and spruce throughfall were similar, indicating no gain of sulphur from the trees. In the inflowing stream, the  delta  super(34)S value increased as discharge decreased, from + 5.57 ppt spring to + 26.21 ppt in summer, indicating bacterial sulphate reduction. The fluctuations in the inlet water were damped by the lake and in the outlet water, only a small decrease in the  delta  super(34)S value during spring discharge was observed.
AN: 2805125

                                                                    942 of 1521  
TI: Biotic feedbacks in lake phosphorus cycles.
AU: Carpenter,-S.R.; Cottingham,-K.L.; Schindler,-D.E.
AF: Cent. Limnol., 680 N. Park St., Univ. Wisconsin, Madison, WI 53706, USA
SO: TRENDS-ECOL.-EVOL. 1992. vol. 7, no. 10, pp. 332-336
LA: English
ER: F (Freshwater)
AB: Limnologists are now reconsidering the role of the biota in the phosphorus (P) cycles of lakes. Changes in the lake communities can have significant consequences for ecosystem P cycles. At seasonal timescales, the relative importance of nitrogen (N) and P as limiting factors for primary production depends in part on zooplankton species composition. Phosphorus storage and recycling by fish and zooplankton can be large components of P budgets, and mobile consumers can be important vectors in P transport. Stability, resilience and resistance of lake P cycles may depend heavily on fluxes to and from upper trophic levels.
AN: 2804892

                                                                    943 of 1521  
TI: Determination of phytoplankton chlorophyll concentrations in the Chesapeake Bay with aircraft remote sensing.
AU: Harding,-L.W.,Jr.; Itsweire,-E.C.; Esaias,-W.E.
AF: Univ. Maryland Sea Grant Coll., 1123 Taliaferro Hall, College Park, MD 20742, USA
SO: REMOTE-SENS.-ENVIRON. 1992. vol. 40, no. 2, pp. 79-100
LA: English
ER: M (Marine); B (Brackish)
AB: This article describes remote sensing measurements of the distribution of phytoplankton chlorophyll concentrations in the Chesapeake Bay during 1989. The goal of this study was to show that remote sensing from light aircraft can complement and extend measurements made from traditional platforms and provide data of improved temporal and spatial resolution, leading to a better understanding of phytoplankton dynamics in the estuary. We followed the developments of the winter-spring diatom bloom in the polyhaline to mesohaline regions of the estuary and of the late-spring and summer dinoflagellate blooms in oligohaline and mesohaline regions.
AN: 2799956

                                                                    944 of 1521  
TI: New and recycled primary production in an oligotrophic lake: Insights for summer phosphorus dynamics.
AU: Caraco,-N.F.; Cole,-J.J.; Likens,-G.E.
AF: Inst. Ecosyst. Stud., New York Bot. Gard., Box AB, Millbrook, NY 12545-0129, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 3, pp. 590-602
LA: English
ER: F (Freshwater)
AB: Primary production that is supported by new inputs of nutrients from outside the system is distinct from production that is supported by remineralization of nutrients within the system. We applied the concept of new production to Mirror Lake, New Hampshire, and our view of P dynamics in this lake was altered dramatically. New production during midsummer put a large demand on P in surface waters, removing 37  mu mol P m super(-2)/d. Without new inputs of P, the P content of surface waters would drop to zero in < 1 month. There is, however, a slight increase, not a decrease, in P content of surface waters during summer stratification. Inputs to surface waters during summer months must, therefore, be large. We now believe that higher than average P loading to the lake occurs in summer, despite low runoff inputs.
AN: 2799318

                                                                    945 of 1521  
TI: Detritus, macrophytes and nutrient cycling in lakes.
AU: Wetzel,-R.G.
AF: Dep. Biol., Univ. Alabama, Tuscaloosa, AL 35487, USA
SO: SCIENTIFIC-PERSPECTIVES-IN-THEORETICAL-AND-APPLIED-LIMNOLOGY. De-Bernardi,-R.;Giussani,-G.;Barbanti,-L.-eds. 1990. vol. 47 pp. 233-251
ST: MEM.-IST.-ITAL.-IDROBIOL. vol. 47
LA: English
ER: F (Freshwater)
AB: Detritus in aquatic ecosystems consists of much greater amounts of organic carbon than occur in the biota. Even though most detritus occurs as dissolved organic carbon and most of the organic carbon is relatively recalcitrant to rapid decomposition, the slow degradation of large amounts of organic matter results in ecosystem detrital metabolism usually far in excess of carbon fluxes by the trophic-dynamic grazing and predatory biota. Detritus and metabolism associated with particulate and especially dissolved detritus provides detrital energy essential for the operation and metabolic stability of the entire ecosystem.
AN: 2799317

                                                                    946 of 1521  
TI: The cycling of iron and manganese in the water column of Lake Sammamish, Washington.
AU: Balistrieri,-L.S.; Murray,-J.W.; Paul,-B.
AF: U.S. Geol. Surv., Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 3, pp. 510-528
LA: English
ER: F (Freshwater)
AB: Processes controlling the distribution and mobility of Fe and Mn in Lake Sammamish, Washington, a seasonally anoxic lake, are deduced from a year-long monthly study of physical, chemical, and biological parameters in the lake. Inventories of dissolved Mn and Fe in the bottom waters increase as the redox potential lowers with dissolved Mn inventories during stagnation being much larger than inventories of dissolved Fe. The shapes of the dissolved metal profiles indicate that dissolved Fe is supplied to the hypolimnion during stratification by diffusion of Fe(II) from the sediments into the overlying anoxic water as well as reduction of Fe oxide particles settling through the anoxic water column, while the dominant source of dissolved Mn to the anoxic bottom waters during most of the stratification period appears to be reduction of settling Mn-oxide particles. Inventories of particulate Fe in the hypolimnion during the latter stages of stratification are significantly larger than inventories of particulate Mn.
AN: 2798185

                                                                    947 of 1521  
TI: The biogeochemical cycling of trace metals in the water column of Lake Sammamish, Washington: Response to seasonally anoxic conditions.
AU: Balistrieri,-L.S.; Murray,-J.W.; Paul,-B.
AF: U.S. Geol. Surv., Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 3, pp. 529-548
LA: English
ER: F (Freshwater)
AB: Total acid-soluble and dissolved Cd, Co, Cr, Cu, Ni, Pb, and Zn concentrations in the water column of a seasonally anoxic lake (Lake Sammamish, Washington) were measured on a monthly basis during the course of a year. These data, in conjunction with Fe, Mn, sulfide, and nutrient data, are used to assess the biochemical processes controlling the distribution of trace metals in the lake and how the importance of these processes varies with time. Thermodynamic calculations are used to examine changes in dissolved metal speciation in the bottom waters during the year and to assess the saturation state of metal-sulfide phases. Spatial and temporal changes in the redox conditions of the bottom waters result in increases in dissolved Co and Ni concentrations, peaks in particulate Co profiles, decreases in dissolved Cu and Cr concentrations, and significant changes in dissolved metal speciation during stagnation. The redox-driven cycling of Fe and Mn in the hypolimnion has a dramatic effect on Co distributions, a slight effect on Ni concentrations, and virtually no effect on Cd, Cu, Cr, and Zn concentrations. Biological uptake and regeneration processes result in a correlation between Zn and silicate concentrations throughout the water column, and it appears that biological cycling may also influence the distribution of Cd.
AN: 2797995

                                                                    948 of 1521  
TI: Changes in the balances of non-fossil carbon, nitrous oxide and dimethyl sulfide in the North Sea.
AU: Hoppema,-J.M.J.; De-Baar,-H.J.W.
CA: Nederlands Inst. voor Onderzoek der Zee, Texel (Netherlands)
SO: 1991. 92 pp
NT: NTIS Order No: PB92-104850/GAR.
LA: English
ER: M (Marine)
AB: The overview provides an assessment of the current knowledge of the anthropogenic impact on the possible emission or uptake of the radiatively-important gases CO2, CH4, N2O and DMS by the North Sea, with special emphasis on the continental shelf waters of the Netherlands. The final objective would be to describe the undisturbed biogeochemical cycles in which these gases are involved, but unfortunately in most cases anthropogenic influence has been exerted for many years and in the absence of historical records of measurements it is impossible to reconstruct the original situation (approx 1860). Therefore, one is restricted to a description of the present-day cycles along with an assessment of the changes that already took place. For understanding the changes in the cycling of radiatively-important gases caused by anthropogenic activity it is necessary to know the processes and mechanisms that determine biogeochemical transformations within these cycles. For this purpose the most important production and consumption processes and the transfers of the matter through the overall North Sea reservoir were treated as well.
AN: 2797132

                                                                    949 of 1521  
TI: Pyrosoma atlanticum  (Tunicata, Thaliacea): Grazing impact on phytoplankton standing stock and role in organic carbon flux.
AU: Drits,-A.V.; Arashkevich,-E.G.; Semenova,-T.N.
AF: Inst. Oceanol., Acad. Sci., 117218, Krasikova 23, Moscow, Russia
SO: J.-PLANKTON-RES. 1992. vol. 14, no. 6, pp. 799-809
LA: English
ER: M (Marine)
AB: Pyrosomas are a large group of pelagic tunicates whose trophic role in pelagic communities has not yet been sufficiently studied. We ran across a local area of high concentration of the most widespread and commonest species of pyrosomas, Pyrosoma atlanticum , 450 miles off the Congo river mouth. The following was estimated: gut pigment content, defecation rate, organic carbon and pigment content of fecal pellets, and sinking rate. Based on these data and the measured number of pyrosomas colonies the grazing impact on phytoplankton and the fecal pellet flux were calculated. During the night swarms of 50-65 mm P. atlanticum  removed 53% of phytoplankton standing stock in the 0-10 m layer; sparsely distributed pyrosomas consumed only 4%. The grazing impact in the 0-50 m layer was only 12.5 and < 1% respectively. We believe that given the sinking rate of 70 m/day the main part of fecal material does not leave the upper water column and is retained in the trophic web of the epipelagic layer.
AN: 2796436

                                                                    950 of 1521  
TI: Contribution of the different planktonic microbial assemblages to ETS activity in the Ligurian frontal area: North-West Mediterranean Sea.
AU: Savenkoff,-C.; Silva,-N.L.; Lefevre,-D.; Denis,-M.; Rassoulzadegan,-F.
AF: Cent. Oceanol. Marseille, CNRS URA 41, Parc Sci. et Technol. Luminy, Case 901, 13288 Marseille Cedex 9, France
SO: J.-PLANKTON-RES. 1992. vol. 14, no. 6, pp. 835-850
LA: English
ER: M (Marine)
AB: Spatial and size distribution of microorganisms and their ETS activity has been investigated in Ligurian Sea surface waters along the Nice-Calvi transect across frontal areas from 18 to 37 km offshore. Aplastidic and plastidic nanoflagellates and aplastidic picoflagellates were present in numbers close to 0.25 x 10 super(4) cells/ml, whereas plastidic picoflagellates accounted for about half this number. Correlations have been evidenced between plastidic and aplastidic micro-organisms within the same size group, suggesting that they belong to a well-defined ecosystem. The highest correlation between total ETS activity and abundance of the considered size groups was observed for nanoflagellates (r = 0.94, n = 22, and r = 0.90, n = 22 for aplastidic and plastidic cells respectively). The importance of the role of nanoflagelaltes in surface waters, with respect to the overall ETS activity, was supported by results from size fractionation which assigned to the 3-10  mu m size range a 73.3% contribution to overall ETS activity. Results emphasize analysing global ETS activity of natural samples in order to derive relationships between the different populations present in the sampled water. It is suggested that coupling flow cytometry to the ETS approach should be very helpful in that respect.
AN: 2796054

                                                                    951 of 1521  
TI: Multiparametric investigation of North Sea particulate matter. Preliminary results in the Skagerrak.
OT: Etude multiparametrique des particules en Mer du Nord: Resultats preliminaires dans le Skagerrak
AU: Boust,-D.; Dupont,-J.P.; Bienvenu,-P.; Ezat,-U.; Lafite,-R.; Leboulanger,-T.; Vinchon,-C.; Albarede,-F.
AF: Lab. Radioecol. Mar., Cent. La Hague, Comm. Energ. Atom., B.P. 508, 50105 Cherbourg Cedex, France
CO: Int. Symp. sur l'Environnement des Mers Epicontinentales, Lille (France), 20-22 Mar  1990
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-ON-ENVIRONMENT-OF-EPICONTINENTAL-SEAS,-LILLE,-20-22-MARCH-1990..  ACTES-DE-COLLOQUE-INTERNATIONAL-SUR-L'-ENVIRONNEMENT-DES-MERS-EPICONTINENTALES,-LILLE,-20-22-MARS-1990. Chamley,-H.-ed. 1991. vol. sp.iss., no. 11 pp. 233-246
ST: OCEANOL.-ACTA. vol. sp.iss., no. 11
LA: English
ER: M (Marine)
AB: During the Tramanor  cruise, in July 1988, seawater and particle samples were collected along a vertical profile (530 m depth) located in the Skagerrak, a crossing-area for different water-masses and particle pools. A sampling strategy was developed to ensure the homogeneity of the different sets of subsamples subjected to analysis by closely-coupled complementary techniques: turbidimetry, granulometry, scanning electron microscope (SEM) observations, Tracor analyses, particulate organic carbon and nitrogen measurements, and neutron activation analysis (NAA). The Baltic outflow is found in the topmost 20 m water-column (salinity  approximately equals 23.5; temperature  approximately equals 18 degree C) overlying North Sea waters (salinity  approximately equals 35; temperature  approximately equals 6 degree C). Surface waters undergo a plankton bloom, dominated by Dinoflagellates and Coccolithophoridae. The former, characterized by high C/N ratios ( approximately equals 15; cellulosic thecae), play a significant role in the biological recycling of Zn. The latter accumulate over the halocline as typically observed in frontal structures. The detrital phase mainly consists of clay minerals. Manganese is highly enriched relative to shale-type material together with Fe, Co and Zn.
AN: 2792439

                                                                    952 of 1521  
TI: Numerical modelling of biological-physical interactions in coastal sites.
OT: Modelisation numerique d'un couplage physico-biologique en milieu cotier
AU: Marcer,-R.; Fraunie,-P.; Dekeyser,-I.; Andersen,-V.
AF: Inst. Mecan. Stat. Turbulence, 13003 Marseille, France
CO: Int. Symp. sur l'Environnement des Mers Epicontinentales, Lille (France), 20-22 Mar  1990
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-ON-ENVIRONMENT-OF-EPICONTINENTAL-SEAS,-LILLE,-20-22-MARCH-1990..  ACTES-DE-COLLOQUE-INTERNATIONAL-SUR-L'-ENVIRONNEMENT-DES-MERS-EPICONTINENTALES,-LILLE,-20-22-MARS-1990. Chamley,-H.-ed. 1991. vol. sp.iss., no. 11 pp. 71-79
ST: OCEANOL.-ACTA. vol. sp.iss., no. 11
LA: French
ER: M (Marine)
AB: This study concerns the numerical simulation of the behaviour of pelagic systems in marine environments by means of a coupled biological and physical model. The physical model is based on the resolution of the Navier-Stokes, temperature and salinity equations in the 3 dimensions of space with a turbulent closure model consisting of 2 supplementary equations ( Kappa - epsilon  model). The tridimensional biological model distinguishes 5 areas: phytoplankton (alive and dead); dissolved inorganic nitrogen; herbivores (essentially copepods); and zooplanktonic wastes (dead bodies and fecal pellets). Other than biological relations (nutrition, excretion,...), the sedimentation of biogenic particles (alive and dead phytoplanktonic cells, dead herbivores) are also considered. The established tridimensional velocity and dissipation fields are used as forcing variables for this biological model. This model has been applied in the case of a real bay configuration: the "baie de Cannes-Mandelieu".
AN: 2792095

                                                                    953 of 1521  
TI: Decomposition activity and nutrient regeneration rates in the hypolimnion of the north basin of Lake Biwa.
AU: Miyajima,-T.
AF: Cent. Ecol. Res., Kyoto Univ., Shimosakamoto, Otsu 520-01, Japan
SO: JAP.-J.-LIMNOL.-RIKUSUIZATSU. 1992. vol. 53, no. 1, pp. 65-73
LA: English
ER: F (Freshwater)
AB: In the course of a recent survey on nutrient dynamics in the north basin of Lake Biwa (Japan), an abundant accumulation of nitrate was observed in the hypolimnion during the stagnation period, and the regeneration rate of nitrogen in the hypolimnion was estimated to be 40.5 mmol/m super(2)/mon. However, it was calculated on the basis of oxygen consumption that the C:N ratio of organic matter mineralized within the hypolimnion should have been 19-21, which suggested a low regeneration efficiency of nitrogen relative to carbon. Dissolved phosphate was found to be accumulated in small concentrations near the bottom, but the regeneration rate of phosphate was very low (0.22 mmol/m super(2)/mon), and the activity of hypolimnetic biota seemed to contributed hardly at all to phosphorus recycling in this basin.
AN: 2791188

                                                                    954 of 1521  
TI: Measurements of nitrogen productivity in the Equatorial Pacific.
AU: Wilkerson,-F.P.; Dugdale,-R.C.
AF: Hancock Inst. Mar. Stud., Dep. Biol. Sci., Univ. Southern California, Los Angeles, CA 90089-6371, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C1, pp. 669-679
LA: English
ER: M (Marine)
AB: During the R/V Wecoma  WEC88 cruise that sampled a meridional transect along 150 degree W from 15 degree N to 15 degree S, uptake of nitrate and ammonium by phytoplankton was measured using  super(15)N with simulated in situ bottle incubations and shipboard mass spectrometry. A set of 25 daily productivity stations showed the influence of equatorial upwelling on nitrate distribution and  super(15)N uptake in a band from 6 degree N to 7.5 degree S compared with the oligotrophic waters to the north and south, with the highest values of nitrate uptake occurring at the equator. During a 5-day time series at the equator, there was an increase in nitrate accompanied by increased nitrate uptake. Nitrate uptake rates at the equator were lower than those predicted by previous investigators. Holdover experiments and uptake versus irradiance curves showed that the phytoplankton there were in an early stage of metabolic adaptation.
AN: 2790910

                                                                    955 of 1521  
TI: Nitrate utilization by plankton in the Equatorial Pacific March 1988 along 150 degree W.
AU: Eppley,-R.W.; Renger,-E.H.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., Univ. California, San Diego, CA 92093, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C1, pp. 663-668
LA: English
ER: M (Marine)
AB: Rates of nitrate utilization were measured in March 1988, from 6 degree N to 8 degree S on longitude 150 degree W in the Pacific Ocean. Surface waters in the equatorial upwelling contained about 5- mu M nitrate. Samples of seawater incubated on deck, as in primary production experiments, lost about 150-nM nitrate during the day and an equal amount at night at the equator. These rates exceeded by several fold the rates of nitrate incorporation into particulate matter. The carbon equivalent of the 24-hour nitrate consumption also exceeded the rate of  super(14)C primary production. The large nitrate consumption is not readily explained in terms of phytoplankton physiology but may serve to fuel speculation on the possible production of dissolved organic nitrogen and on the role of bacteria in processing nitrate in the equatorial Pacific upwelling region.
AN: 2790885

                                                                    956 of 1521  
TI: Photosynthetic characteristics and estimated growth rates indicate grazing is the proximate control of primary production in the Equatorial Pacific.
AU: Cullen,-J.J.; Lewis,-M.R.; Davis,-C.O.; Barber,-R.T.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, N.S. B3H 4J1, Canada
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C1, pp. 639-654
LA: English
ER: M (Marine)
AB: Macronutrients persist in the surface layer of the equatorial Pacific Ocean because the production of phytoplankton is limited. Measurements of photosynthesis as a function of irradiance (P-I) provide information on the control of primary productivity. P-I was measured in the equatorial Pacific along 150 degree W, during February-March 1988. Diel variability of P-I showed a pattern consistent with nocturnal vertical mixing in the upper 20 m followed by diurnal stratification, causing photoinhibition near the surface at midday. Otherwise, the distribution of photosynthetic parameters with depth and the stability of P-I during simulated in situ incubations over 2 days demonstrated that photoadaptation was nearly complete at the time of sampling: photoadaptation had not been effectively countered by upwelling or vertical mixing. Diel variability of beam attenuation also indicated high specific growth rates of phytoplankton and a strong coupling of production with grazing. It appears that grazing is the proximate control on the standing crop of phytoplankton. Nonetheless, the supply of a trace nutrient such as iron might ultimately regulate productivity by influencing species composition and food-web structure.
AN: 2790870

                                                                    957 of 1521  
TI: Zooplankton contribution to particulate phosphorus and nitrogen in lakes.
AU: Hessen,-D.; Andersen,-T.; Faafeng,-B.
AF: Norwegian Inst. Water Res., P.O. Box 69, Korsvoll, N-0808 Oslo 8, Norway
SO: J.-PLANKTON-RES. 1992. vol. 14, no. 7, pp. 937-947
LA: English
ER: F (Freshwater)
AB: Based on the recognition of rather constant species-specific element to dry weight ratios in freshwater zooplankton, pools of metazoan zooplankton P and N were calculated for 45 Norwegian lakes of varying trophy. On the average zooplankton constituted 20.4  plus or minus  12.3% and 4.6  plus or minus  4.3% of particulate P and N respectively. The fraction was considerably higher in many oligotrophic lakes, at most > 50 and 20% respectively, but declined to  similar to 15% (P) and  similar to 5% (N) in meso- to eutrophic lakes. In general, phytoplankton contribution to particulate P was < 50%, leaving a large share of particulate P to bacteria and microzooplankton. The zooplankton proportion of particulate P was only weakly influenced by the predation pressure in terms of fish community structure. Zooplankton P is important in the overall lake metabolism, and knowledge of this pool may be used to estimate zooplankton-mediated loss and regeneration of P and improve total nutrient element budgets in lakes.
AN: 2782133

                                                                    958 of 1521  
TI: Grain size effect on anthropogenic trace metal and organic matter distribution in marine sediments.
AU: Krumgalz,-B.S.; Fainshtein,-G.; Cohen,-A.
AF: Natl. Inst. Oceanogr., Israel Oceanogr. and Limnol. Res., Tel-Shikmona, P.O. Box 8030, Haifa 31080, Israel
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 116, no. 1-2, pp. 15-30
LA: English
ER: M (Marine)
AB: The distribution of anthropogenic trace metals (cadmium, copper, iron, lead and zinc) and organic matter was studied in several fractions of marine sediments. Regression analysis of the data using the "dummy variables" approach proved the existence of anthropogenic trace metal and organic matter partitioning on different size fractions of the sediment particles. The sediment fractions 0.125-0.250 mm and 0.063-0.125 mm in most cases possessed similar "fingerprints" of pollutants' distribution.
AN: 2777875

                                                                    959 of 1521  
TI: Changes in plant community structure following liming of an acidified Adirondack lake.
AU: Bukaveckas,-P.A.; Weiher,-E.R.; Boylen,-C.W.
AF: Inst. Ecosyst. Stud., Millbrook, NY 12545, USA
CO: 32. Annu. Meet. of the Aquatic Plant Management Society and Int. Symp. on the Biology and Management of Aquatic Plants, Daytona Beach, FL (USA), 12-16 Jul 1992
SO: ABSTRACTS-OF-THE-AQUATIC-PLANT-MANAGEMENT-SOCIETY,-INC.-THIRTY-SECOND-ANNUAL-MEETING-AND-INTERNATIONAL-SYMPOSIUM-ON-THE-BIOLOGY-AND-MANAGEMENT-OF-AQUATIC-PLANTS. 1992. pp. 17-18
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Woods Lake has been studied since 1984 to investigate the effects of liming on lake trophic interactions and biogeochemical cycles. Aquatic plant communities were surveyed during 2 years prior to liming (1981 and 1984; lake pH < 5) and for 7 years after liming during which lake pH ranged from 5.5 to 6.5 (1985-1991). The most conspicuous effect associated with liming was the decline of the deep-water plants (depth range = 2-5 m). Utricularia purpurea  was the dominant deep-water plant and accounted for 75% of total plant coverage in Woods Lake. Within 3 years following liming, Utricularia  had declined severely and floating-leaved and canopy-forming species have increased in percent coverage. The most successful of these was Potamogeton epihydrus  which was first observed in the lake 3 years after liming. The shift in plant growth forms from deepwater to canopy-forming species is attributed to the decrease in the transparency of the lake as a result of liming.
AN: 2777629

                                                                    960 of 1521  
TI: Measurements of diffusive sublayer thicknesses in the ocean by alabaster dissolution, and their implications for the measurements of benthic fluxes.
AU: Santschi,-P.H.; Anderson,-R.F.; Fleisher,-M.Q.; Bowles,-W.
AF: Dep. Mar. Sci., Texas A&M Univ., Galveston, TX 77843, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1991. vol. 96, no. C6, pp. 10,641-657
LA: English
ER: M (Marine)
AB: Fluxes of reactive chemical species across the sediment-water interface can profoundly influence the dominant biogeochemical cycles in the worlds ocean. However, reliable in-situ measurements of benthic fluxes of many reactive species cannot be carried out without adjustment of stirring rates inside benthic flux chambers to match boundary layer conditions prevailing outside. A simple method to compare flow levels consists of measurements of gypsum dissolution rates inside benthic chambers and on the seafloor. The measurement of the diffusion-controlled dissolution rate of gypsum allows the estimation of the diffusive sublayer thickness and the time-averaged bottom stress on the seafloor. This method had previously been intercalibrated with the stress sensor method in flumes and the inside benthic chambers. We describe here free-vehicle deployments of alabaster plates on the bottom of the ocean which gave results consistent with hydrodynamic theory.
AN: 2772864

                                                                    961 of 1521  
TI: The African rain forest vegetation and palaeoenvironments during Late Quaternary.
AU: Maley,-J.
AF: ORSTROM, UR A3 et CNRS, UA 327, Lab. Palynol., Univ. Sci. Tech. Languedoc, 34095 Montpellier Cedex 5, France
SO: CLIM.-CHANGE. 1991. vol. 19, no. 1-2, pp. 79-98
NT: Special issue: Tropical forests and climate.
LA: English
ER: F (Freshwater)
AB: This review paper presents first the main pollen results on the vegetation history of the rain forest during the late Quaternary. Other palaeoenvironmental data were obtained by diverse geological analyses of the lacustrine sediments. For Bosumtwi, the relatively precise reconstruction of take-level fluctuations permitted several palaeoclimatic interpretations for the main Holocene phases. By comparison with present-day mountain environments, TOC and TON increase in cool environments, but decrease when warmth and humidity increase, as during Holocene time, because the recycling processes speed up in the topsoil. For the same period the alteration of the soils in the catchment produced a strong increase of kaolinite. All these change intervened ca. 9500 yr BP, which is a key date in tropical Africa. In conclusion, climatic correlations between equatorial and dry north tropical Africa illustrate how changes in the forest block must have important effects on adjacent climatic zones.
AN: 2771594

                                                                    962 of 1521  
TI: Carbon sinks in mangroves and their implications to carbon budget of tropical coastal ecosystems.
AU: Twilley,-R.R.; Chen,-R.H.; Hargis,-T.
AF: Dep. Biol., Univ. Southwestern Louisiana, P.O. Box 42451, Lafayette, LA, USA
CO: Int. Workshop on Natural Sinks of CO sub(2), Palmas Del Mar (Puerto Rico), 24-27 Feb 1992
SO: WATER-AIR-SOIL-POLLUT. 1992. vol. 64, no. 1-2, pp. 265-288
NT: Special issue: Natural sinks of CO sub(2).
LA: English
ER: B (Brackish)
AB: Nearly 50% of terrigenous materials delivered to the world's oceans are delivered through just twenty-one major river systems. These river-dominated coastal margins (including estuarine and shelf ecosystems) are thus important both to the regional enhancement of productivity and to the global flux of C that is observed in land-margin ecosystems. The tropical regions of the biosphere are the most biogeochemically active coastal regions and represent potentially important sinks of C in the biosphere. Rates of net primary productivity and biomass accumulation depend on a combination of global factors such as latitude and local factors such as hydrology.
AN: 2766476

                                                                    963 of 1521  
TI: Inorganic nitrogen metabolism in Ulva rigida  illuminated with blue light.
AU: Corzo,-A.; Niell,-F.X.
AF: Dep. Ecol., Fac. Sci., Univ. Malaga, Campus Teatinos, E-29071 Malaga, Spain
SO: MAR.-BIOL. 1992. vol. 112, no. 2, pp. 223-228
NT: Bibliogr.: 48 ref.
LA: English
ER: M (Marine)
AB: Inorganic nitrogen metabolism in blue light was studied for the green alga Ulva rigida  collected in the south of Spain (Punta Carnero, Algeciras) in the winter of 1987. NH sub(4) super(+) has been reported to inhibit NO sub(3) super(-) uptake; however, U. rigida) showed a net NO sub(3) super(-) uptake even when the NH sub(4) super(+) concentration of the external medium was three or four times greater than the concentration of NO sub(3) super(-). NO sub(3) super(-) uptake rates were similar in both darkness and in blue light of various photon fluence rates (PFR) ranging from 17 to 160  mu mol m super(-2)/s. Since NO sub(3) super(-) uptake is an active mechanism involving the consumption of ATP, respiratory metabolism can provide enough ATP to maintain the energetic requirement of NO sub(3) super(-) transport even in darkness. In contrast, NO sub(3) super(-) reduction in U. rigida) was highly dependent on the net photosynthetic rate. After 7 h in blue light, intracellular NO sub(3) super(-) concentrations ((NO sub(3) super(-)) sub(i)) were higher in specimens exposed to intensities below the light compensation point (LCP) than in those incubated at a PFR above the LCP.
AN: 2764538

                                                                    964 of 1521  
TI: Baseline study on Cd, Cu and Pb concentrations in Atlantic neuston organisms.
AU: Schulz-Baldes,-M.
AF: Alfred-Wegener-Inst. Polar and Mar. Res., D-W 2850 Bremerhaven, FRG
SO: MAR.-BIOL. 1992. vol. 112, no. 2, pp. 211-222
NT: Bibliogr.: 33 ref.
LA: English
ER: M (Marine)
AB: Neuston organisms were caught during 2 Atlantic expeditions (1982 and 1987) between 48 degree N and 40 degree S. About 1200 individuals from 19 taxa were analysed for cadmium, copper and lead. The distribution of metal concentrations was log-normal and thus best described by the median and the percentiles. Fourteen taxa with sample numbers larger than 20 were subjected to a logarithmic regression of weight vs metal concentration. The metal concentrations from populations with significant correlations were then weight-corrected: eight populations for lead, five for cadmium and four for copper. When grouped into ecological categories the pleuston organisms displayed significantly higher cadmium concentrations than the euneuston, which in turn had higher values than the pseudo- and/or facultative neuston. The relative deviation from the median was used in an averaging operation to obtain a broader spatial resolution of the neuston-bound metals, based on 16 taxa which were encountered at 10 or more stations.
AN: 2764521

                                                                    965 of 1521  
TI: Heavy metals in stream sediments: Effects of human activities.
AU: Mantei,-E.J.; Foster,-M.V.
AF: Geosci. Dep., Southwest Missouri State Univ., Springfield, MO, USA
SO: ENVIRON.-GEOL.-WATER-SCI. 1991. vol. 18, no. 2, pp. 95-104
LA: English
ER: F (Freshwater)
AB: The content of 11 heavy metals in the sediments of a stream system was determined by atomic absorption analysis. Geochemical phases were investigated using a sequential extraction scheme, and bulk contents were assessed with a single HNO sub(3) extraction. Certain heavy metals were associated with different geochemical phases. Results from the geochemical phases indicated Cu, Pb, Zn, Cd and Ag were emitted by one landfill, while Cd, Ba, and Ag were emitted by a second landfill. A wastewater treatment facility appeared to emit Ni and Cu. A stream draining a reservoir and joining the study stream resulted in dilution of the heavy metals in the sediments. A populated area along the study stream appeared to emit Mn. The single HNO sub(3) extraction procedure is quicker to perform than the sequential extraction but does not indicate the phase associations.
AN: 2761367

                                                                    966 of 1521  
TI: Investigations into the chemical forms of  super(239)Pu in a West Cumbrian saltmarsh soil radiolabelled by an environmental process.
AU: Bulman,-R.A.; Wedgwood,-A.J.; Szabo,-G.
AF: Natl. Radiol. Prot. Board, Chilton, Didcot OX11 0RD, UK
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 114, pp. 215-226
LA: English
ER: M (Marine); B (Brackish)
AB: New procedures have been developed to demonstrate the nature of binding of  super(239)Pu in a saltmarsh soil. Evidence is presented which shows that there is a small  super(239)Pu component which is present in a form which can be extracted by chelating agents which are similar to naturally occurring chelating agents. By in-situ derivatization procedures it has been possible to isolate two forms of complexed Pu. The effectiveness of humates as sinks for Pu(IV) and Am(III) have been modelled by using some novel forms of humic and fulvic acids chemically immobilized upon silica.
AN: 2761098

                                                                    967 of 1521  
TI: Temporal variations of  super(234)Th activity in the water column of Dabob Bay: Particle scavenging.
AU: Wei,-Ching-Ling; Murray,-J.W.
AF: Inst. Oceanol., Natl. Taiwan Univ., P.O. Box 23-13, Taipei, Taiwan
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 2, pp. 296-314
LA: English
ER: M (Marine)
AB: Monthly measurements of total, dissolved, and particulate  super(234)Th, along with fluxes of total mass and particulate  super(234)Th, were made throughout 1987 in Dabob Bay, Washington. Vertical distributions of total  super(234)Th showed a large deficiency relative to  super(238)U throughout the water column during all sampling periods. Total  super(234)Th activities in surface waters were generally higher in winter and lower in summer, in response to seasonal biological activity. In spite of this variation, the steady state assumption seems valid for modeling  super(234)Th of the bay because the magnitude of variation is insignificant in the mass balance calculation. The range of residence times of total, dissolved, and particulate  super(234)Th estimated from an irreversible scavenging model are 4-70, <1-10, and 3-60 d, respectively. The residence time of  super(234)Th is controlled by the suspended particles whose distribution is determined by biological production in the surface layer and resuspension of bottom sediments.
AN: 2759320

                                                                    968 of 1521  
TI: Importance of benthic productivity in controlling the flux of dissolved inorganic nitrogen through the sediment-water interface in a hypertrophic marine ecosystem.
AU: Krom,-M.D.
AF: Dep. Earth Sci., Leeds Univ., Leeds LS2 9JT, UK
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 78, no. 2, pp. 163-172
LA: English
ER: M (Marine)
AB: The rate of bacterial nitrate reduction measured directly in sediments from a hypertrophic marine ecosystem (6.0  plus or minus  1.5 mmol m super(-2) d super(-1)) was similar to the value calculated from a whole pond nutrient budget (7.7  plus or minus  0.3 mmol m super(-2) d super(-1)) during a phytoplankton crash period. Organic matter breakdown in the sediments represented the dominant source of ammonia-N to the system (16.09 mmol m super(-2) d super(-1) compared to 2.97 mmol m super(-2) d super(-1) directly from fish excretion and 0.28 mmol m super(-2) d super(-1) in the inflow). However most, if not all, of this ammonia-N did not reach the water column as shown by a total nutrient budget for the pond. It was intercepted by the benthic flora and used to support high levels of benthic productivity (246 mmol O m super(-2) d super(-1); 29.72 mmol N m super(-2) d super(-1)). The benthic productivity was calculated by correcting the total system gross production (determined by a total oxygen budget) for water column productivity measured by in situ incubated light/dark bottles.
AN: 2756283

                                                                    969 of 1521  
TI: Sulfate-reducing bacteria in temporarily oxic sediments with bivalves.
AU: Bussmann,-I.; Reichardt,-W.
AF: GEOMAR, Forschungszent. Mar. Geowiss., Wischofstr. 1-3, D-W 2300 Kiel 14, FRG
SO: MAR.-ECOL.-PROG.-SER. vol. 78, no. 1, pp. 97-102
LA: English
ER: M (Marine)
AB: Under seasonally fluctuating redox conditions in sediment of Kiel Bay (eastern Baltic Sea), viable counts (MPN) of sulfate-reducing bacteria (SRB) ranged between 4 x 10 super(2) and 7 x 10 super(4) cm super(-3). These MPN appeared fairly independent of ambient redox potentials and followed peaks of phytoplankton productivity in the water column with a time lag of 2 to 3 wk. The relative proportions of SRB using acetate, lactate or succinate as their electron donors fluctuated widely. Shells of the clam Arctica islandica , which can survive anoxia, were, even in oxic sediments, colonized by epizoic SRB. Significant differences between the abundance of epizoic SRB and SRB from ambient sediment were not detected. In terms of enrichment kinetics, however, epizoic SRB, and particularly those depending on succinate as electron donor, showed quicker responses.
AN: 2756134

                                                                    970 of 1521  
TI: Fluids in convergent margins: What do we know about their composition, origin, role in diagenesis and importance for oceanic chemical fluxes?.
AU: Kastner,-M.; Elderfield,-H.; Martin,-J.B.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0212, USA
SO: THE-BEHAVIOUR-AND-INFLUENCE-OF-FLUIDS-IN-SUBDUCTION-ZONES:-A-DISCUSSION-HELD-8-9-NOV.-1990. Tarney,-J.;Pickering,-K.T.;Knipe,-R.J.;Dewey,-J.F.-eds. 1991. vol. 335, no. 1638 pp. 243-259
ST: PHILOS.-TRANS.-R.-SOC.-LOND.,-SER.-A. vol. 335, no. 1638
LA: English
ER: M (Marine)
AB: The nature and origin of fluids in convergent margins can be inferred from geochemical and isotopic studies of the venting and pore fluids, and is attempted here for the Barbados Ridge, Nankai Trough and the convergent margin off Peru. Venting and pore fluids with lower than seawater Cl super(-) concentrations characterize all these margins. Fluids have two types of source: internal and external. The three most important internal sources are: porosity reduction; diagenetic and metamorphic dehydration; and the breakdown of hydrous minerals. Gas hydrate formation and dissociation, authigenesis of hydrous minerals and the alteration of volcanic ash and/or the upper oceanic crust lead to a redistribution of the internal fluids and gases in vertical and lateral directions.
AN: 2755375

                                                                    971 of 1521  
TI: Cadmium in the North Sea -- a mass balance.
AU: Kuehn,-W.; Radach,-G.; Kersten,-M.
AF: Inst. Meeresknd., Univ. Hamburg, Troplowitzst. 7, D-2000 Hamburg 54, FRG
SO: J.-MAR.-SYST. 1992. vol. 3, no. 3, pp. 209-224
LA: English
ER: M (Marine)
AB: Based on recently published data on cadmium concentrations in the different compartments of the North Sea ecosystem, i.e. water, suspended particulate matter, biota and sediments, and based on 3D circulation simulations, a (preliminary) mass balance for cadmium in the North Sea was worked out by estimating the contents in the compartments as well as the advective and other fluxes into/out of and within the system. It terns out that the total cadmium content in the water of 810  plus or minus  320 t is in the same order of magnitude as the amount of cadmium in the sediment 1000  plus or minus  500 t. The net deposition flux of cadmium to the sediments (8 t/yr) amounts only to about 3% of the annual anthropogenic input. The amount of cadmium in the biota is about 63  plus or minus  12 t, but the annual turnover of cadmium due to primary production, herbivorous grazing and remineralisation is at least of the same order. The anthropogenic cadmium input from rivers, atmosphere and direct discharges of 310  plus or minus  185 t/yr would add again the total cadmium content in the water in about 2.6 yr. The flushing of the North Sea circulation is very effective: in about 0.7 yr the cadmium contained in the water of the North Sea would be washed out, if no new cadmium would be introduced. The net outflow of cadmium across the northern boundary (307 t/yr) is equal to the anthropogenic input.
AN: 2755365

                                                                    972 of 1521  
TI: Large lakes and their sustainable development.
AU: Tilzer,-M.M.; Bossard,-P.
AF: Limnol. Inst., Univ. Konstanz, Mainaustr. 212, D-7750 Konstanz, FRG
SO: AQUAT.-SCI. 1992. vol. 54, no. 2, pp. 91-103
LA: English
ER: F (Freshwater)
AB: This contribution has been edited from a working document, prepared by invited scientists attending a workshop in Konstanz, Germany, on the importance of external perturbations for short- and long-term changes in large lakes ecosystems, held from 21 to 26 October, 1991. It tries to assess our current understanding of the most important processes involved in the functioning of large lakes and to identify the currently most urgent research priorities in the fields of land-water interactions, physical processes, biogeochemistry and nutrient relations, remote sensing, biological interactions in food webs, and long-term monitoring programs.
AN: 2752969

                                                                    973 of 1521  
TI: Role of the marine biosphere in the global carbon cycle.
AU: Longhurst,-A.R.
AF: Biol. Oceanogr. Div., Bedford Inst. Oceanogr., Dep. Fish. and Oceans, P.O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
CO: American Society of Limnology and Oceanography Symp.: What Controls Phytoplankton Production in Nutrient-Rich Areas of the Open Sea?, San Marcos, CA (USA), 22-24 Feb 1991
SO: LIMNOL.-OCEANOGR. 1991. vol. 36, no. 8, pp. 1507-1526
LA: English
ER: M (Marine)
AB: The geochemical disequilibrium of our planet is due mainly to carbon sequestration by marine organisms over geological time. Changes in atmospheric CO sub(2) during interglacial-glacial transitions require biological sequestration of carbon in the oceans. Nutrient-limited export flux from new production in surface waters is the key process in this sequestration. The most common model for export flux ignores potentially important nutrient sources and export mechanisms. Export flux occurs as a result of biological processes whose complexity appears not to be accommodated by the principal classes of simulation models, this being especially true for food webs dominated by single-celled protists whose trophic function is more dispersed than among the multicelled metazoa. The fashionable question concerning a hypothetical "missing sink" for CO sub(2) emissions is unanswerable because of imprecision in our knowledge of critical flux rates. This question also diverts attention from more relevant studies of how the biological pump may be perturbed by climatic consequences of CO sub(2) emissions. Under available scenarios for climate change, such responses may seem more likely to reinforce, rather than mitigate, the rate of increase of atmospheric CO sub(2).
AN: 2752528

                                                                    974 of 1521  
TI: Are the trace metal cycles balanced in the Mediterranean Sea?.
AU: Ruiz-Pino,-D.P.; Jeandel,-C.; Bethoux,-J.-P.; Minster,-J.-F.
AF: LPCM, Quai Darse, 06230-Villefranche sur Mer, France
SO: GLOBAL-PLANET.-CHANGE. 1990. vol. 2, no. 3-4, pp. 369-388
NT: Special Issue: 25 years of physical climatology.
LA: English
ER: M (Marine)
AB: The budgets of Cr, V, Pb, Cd and P have been determined in the Mediterranean Sea. The water flows are described with a 4-box model which distinguishes surface (100 m depth) and deep layers in both western and eastern basins. Trace metal and phosphate concentrations are derived from vertical profiles, established during the PHYCEMED II cruise. The homogeneity of these profiles and the "non-nutrient-like" behavior of Mediterranean trace metal are explained by noticeable external inputs, strong vertical mixing characterizing its hydrology in addition to an unsufficient biological removal. Through the Gibraltar strait, the Mediterranean Sea exports roughly 470, 160 and 330 tons/yr of Cr, Cd and P towards the Atlantic Ocean respectively, whereas 6480 tons/yr of V and 470 tons/y of Pb are imported. The estimations of Total Dissolved Budgets and Deep Waters Budgets show that Mediterranean Cr budget is in deficit whereas V, Pb and Cd ones are in excess. Deep water scavenging/remobilization processes are invoked to equilibrate these budgets. Remobilization of 11-18.10 super(-5) g m super(-2) yr super(-1) of Cr--in agreement with previous results--may explain this element budget. On the other hand, disequilibrated lead Mediterraneran budget can be explained by a non-steady-state situation, which is tested through runs of the 4-box model.
AN: 2748649

                                                                    975 of 1521  
TI: Annual cycle of benthic nutrient fluxes in Tomales Bay, California, and contribution of the benthos to total ecosystem metabolism.
AU: Dollar,-S.J.; Smith,-S.V.; Vink,-S.M.; Obrebski,-S.; Hollibaugh,-J.T.
AF: Hawaii Inst. Mar. Biol., Univ. Hawaii, Honolulu, HI 96822, USA
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 79, no. 1-2, pp. 115-125
NT: Bibliogr.: 28 ref.
LA: English
ER: M (Marine)
AB: Benthic fluxes of dissolved nutrients, oxygen, dissolved inorganic carbon, and total alkalinity were measured over a 2 yr period in Tomales Bay, California, USA, using in situ incubation chambers. Release of dissolved nutrients from the sediment peaked in late summer and was lowest in winter. The difference between C:N:P flux ratios and composition of suspended particulates indicated the existence of a sink for regenerated N, relative to C and P. Total alkalinity flux revealed that carbon metabolism by net sulfate reduction represented ca one-third of total benthic metabolism. Partitioning net system fluxes into component fluxes suggested that the equivalent of ca 70 to 80% of the available particulate C, N and P was respired within the water column, while about 20 to 30% was respired by the benthos. During spring, increasing light resulted in higher water column productivity, followed closely by rising water column respiration. With low delivery of the new organic material to the benthos, and low residual organics in the sediment, benthic respiration remained low.
AN: 2747695

                                                                    976 of 1521  
TI: (Aquatic microbiology in the FRG.).
OT: Stand und Perspektiven der Gewaesser-mikrobiologie in der Bundesrepublik Deutschland
AU: Overbeck,-J.; Rheinheimer,-G.; Gunkel,-W.; Krumbein,-W.E.; Weyland,-H.
AF: Max-Planck-Inst. Limnol., W-2320 Ploen, FRG
SO: NATURWISSENSCHAFTEN. 1991. vol. 78, no. 12, pp. 543-556
LA: German
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Intensive studies on microbial communities in marine and freshwater ecosystems started in the Federal Republic of Germany in the 1960's. It became soon apparent that a real understanding of biogeochemical cycles without consideration of microorganisms is impossible. It was realized that the classical grazing and detritus food chains should be replaced by various microbial loops connecting all trophic levels responsible for the complex food web. Recent approaches apply increasing biochemical and molecular methods for studying the role of microorganisms in aquatic ecosystems.
AN: 2747379

                                                                    977 of 1521  
TI: Vertical profiles of some natural radionuclides over the Alpha Ridge, Arctic Ocean.
AU: Bacon,-M.P.; Huh,-C.-A.; Moore,-R.M.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: EARTH-PLANET.-SCI.-LETT. 1989. vol. 95, no. 1-2, pp. 15-22
LA: English
ER: M (Marine)
AB: Concentration profiles of  super(228)Ra,  super(234)Th,  super(230)Th,  super(232)Th,  super(228)Th, and  super(231)Pa were measured in the CESAR Ice Camp water column (85 degree 50'N, 108 degree 50'W). Thorium isotopes were determined in both dissolved and particulate forms. The results show that rates of scavenging of the reactive nuclides are unusually low, even in comparison with other oligotrophic oceans. Application of a reversible exchange model to the Th isotope data suggests that Th cycling is measurably faster in the surface water than it is at depth.
AN: 2744292

                                                                    978 of 1521  
TI: Nutrient control of phytoplankton photosynthesis in the western North Atlantic.
AU: Platt,-T.; Sathyendranath,-S.; Ulloa,-O.; Harrison,-W.G.; Hoepffner,-N.; Goes,-J.
AF: Biol. Oceanogr. Div., Bedford Inst. Oceanogr., Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
SO: NATURE. 1992. vol. 356, no. 6366, pp. 229-231
LA: English
ER: M (Marine)
AB: The authors report results from several years of oceanographic cruises, showing that the parameters of the photosynthesis-light curve for the flora of the North Sargasso Sea are remarkably constant in magnitude, except during the spring phytoplankton bloom when their magnitudes are noticeably higher. They interpret these results as providing direct evidence for nutrient control of photosynthesis in the open ocean. Our findings also reinforce the plausibility of using biogeochemical provinces to partition the ocean into manageable units for basin- or global-scale analysis, show that seasonal changes in critical parameters should not be overlooked if robust carbon budgets are to be constructed, and illustrate the value of attacking the parameters that control the key fluxes, rather than the fluxes themselves, when investigating the ocean carbon cycle.
AN: 2744136

                                                                    979 of 1521  
TI: Impact of Arenicola marina  on bacteria in intertidal sediments.
AU: Grossmann,-S.; Reichardt,-W.
AF: Alfred-Wegener-Inst. Polar- und Meeresforsch., P.O. Box 120161, D-W 2850 Bremerhaven, FRG
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 77, no. 1, pp. 85-93
LA: English
ER: M (Marine)
AB: On intertidal flats of the North Frisian Wadden Sea, total abundance and biomass of bacteria were examined at 6 sites in the particle transport system of Arenicola marina  burrows. Both bacterial abundance and biomass showed maxima on the input side, with distinctive peaks in the polychaete's foregut (oesophagus), and declined on the egestive side (hindgut and fecal casts) by 70%. Cell sizes did not differ significantly among sampling sites. In feeding experiments using fluorochrome-labelled (killed) bacteria and indigestible fluorescent particles as a reference standard, disappearance rates of total bacterial biomass were 80 to 90%. Gut extracts showed lysozyme activity. Peaks of bacterial densities in sediment samples from the foregut region that did not appear in the feeding experiments with killed bacteria suggest "gardening". Despite high variances, decreasing viable counts of bacteria on nutrient agar noted between paired foregut and hindgut samples indicated selective survival.
AN: 2744043

                                                                    980 of 1521  
TI: Hydrothermal vent systems.
AU: Tivey,-M.K.
AF: Chem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: OCEANUS. 1991. vol. 34, no. 4, pp. 68-74
NT: Special issue: Mid-Ocean Ridges.
LA: English
ER: M (Marine)
AB: Hydrothermal systems transfer large amounts of heat and mass from Earth's interior to the oceans. Fluids exiting the chimneys are metal-rich, hot, and acidic, and vent at velocities on the order of meters per second. A striking feature of black smoker chimneys is how remarkably thin their walls are: they vary in thickness from about 5 inches to as little as .25 of an inch. Across this thin layer is a temperature difference of 300 degree C or greater, and similar steep elemental composition gradients also exist. Chimney structures are thus fascinating subjects for scientific study.
AN: 2743929

                                                                    981 of 1521  
TI: Cooperative studies of mid-ocean ridges.
AU: Blackman,-D.; Stroh,-T.
AF: Dep. Geol., Univ. Washington, WA 98105, USA
SO: OCEANUS. 1991. vol. 34, no. 4, pp. 21-23
NT: Special issue: Mid-Ocean Ridges.
LA: English
ER: M (Marine)
AB: The Ridge Inter-Disciplinary Global Experiments (RIDGE) Initiative is a cooperative effort to study the mid-ocean ridges as a dynamic global system of focused energy flow from Earth's interior outward. The National Science Foundation supports the RIDGE Initiative, part of the US Global Change Research Program, through both its Global Change and Ocean Sciences divisions. The program's key goals include: characterizing the global ridge structure; understanding crustal accretion and upper-mantle dynamics; charting the variability over time of volcanic and hydrothermal systems; mapping biological colonization and evolution at ridge crests; determining biological colonization and evolution at ridge crests; determining the properties of multiphase materials at ridge crests; and developing technology for ridge-crest experimentation.
AN: 2743817

                                                                    982 of 1521  
TI: Bacterial number, heterotrophy and extracellular enzyme activity in the Bransfield Strait, Antarctica.
AU: Kim,-S.-J.
AF: Mar. Microbiol. Lab., Korea Ocean Res. and Dev. Inst., Ansan P.O. Box 29, 425-600 Seoul, Rep. Korea
CO: 2. Int. Symp. on Antarctic Science, Seoul (Korea), 17-18 Sep 1990
SO: SECOND-INTERNATIONAL-SYMPOSIUM-ON-ANTARCTIC-SCIENCE. 1991. vol. 2, no. 1 pp. 9-16
ST: KOREAN-J.-POLAR-RES. vol. 2, no. 1
NT: Special Issue.
LA: English
ER: M (Marine)
AB: To study the structure and function of bacterial populations in the Bransfield Strait, Antarctica, which is located between 62 degree  similar to 64 degree S and 56 degree  similar to 62 degree W, twenty nine sampling stations were chosen. Samples were collected from sea water and sediment during austral summer (Dec. 1989 similar to Jan. 1990) and analyzed for total bacterial number, total saprophytic bacterial number, heterotrophic activity and extracellular enzyme activity. The number of total bacteria in sea water was between 1.0 x 10 super(4) cells/ml and 1.6 x 10 super(5) cells/ml, and total saprophytic bacteria were between 0.5 x 10 super(2) CFU/l and 8.0 x 10 super(4) CFU/l in their numbers. The population density of saprophytic bacteria was significantly low, giving less than 10 super(-4) of the total bacterial number, in this region. Turnover times of glucose and leucine in sea water were in the ranges of 41 and 2094 hrs, and 56 and 980 hrs, respectively. Turnover times of these organic matters were extremely variable depending on the sampling station and water depth.
AN: 2739612

                                                                    983 of 1521  
TI: A fluctuating water-level chamber for biogeochemical experiments in tidal marshes.
AU: Chambers,-R.M.
AF: Tiburon Cent., Box 855, Tiburon, CA 94920, USA
SO: ESTUARIES. 1992. vol. 15, no. 1, pp. 53-58
LA: English
ER: B (Brackish)
AB: An experimental chamber is described which is closed to the water column but encompasses a selected section of the marsh surface. The microcosm is connected to a subsurface collapsible reservoir which functions as a flood water source. Head differences due to tidal fluctuations force reservoir water into and out of the microcosm, so that over complete tidal cycles the net exchanges of materials can be quantified. For this study, seasonal patterns of ammonium and phosphate dynamics in a tidal freshwater marsh were determined using four experimental chambers. On average, phosphate was removed from the water column during the spring, and released to the water column during summer and early fall. Seasonal patterns of ammonium dynamics were less clear, but the marsh removed ammonium from the water column on two of three summer sampling dates. Ammonium and phosphate removal from replicated chambers in vegetated sections of the marsh complex was greater than from unvegetated sections, indicating spatial heterogeneity of nutrient processing. The use of chambers in tidal marshes creates the opportunity to run controlled experiments in situ without imposing artificial hydrologic regimes.
AN: 2737071

                                                                    984 of 1521  
TI: Stable carbon isotope ratios of plankton carbon and sinking organic matter from the Atlantic sector of the Southern Ocean.
AU: Fischer,-G.
AF: Fachber. Geowiss., Univ. Bremen, Klagenfurter Str., D-2800 Bremen 33, FRG
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 581-596
LA: English
ER: M (Marine)
AB: The stable carbon isotope composition of particulate organic carbon (POC) from plankton, sediment trap material and surface sediments from the Atlantic sector of the Southern Ocean were determined. Large variations in the  delta  super(13)C values of plankton were measured.  super(13)C enrichments of up to 10 ppt coincided with a change in the diatom assemblage and a two-fold increase in primary production. This may result in diffusion limitation reducing the magnitude of the isotope fractionation. The  delta  super(13)C values of plankton from sea-ice cores display a relationship with the chlorophyll a content. In comparison with plankton, sinking krill faeces sampled by traps can be enriched by 2-5 ppt in  super(13)C. The transport of particles in other faeces, diatom aggregates or chains results in minor isotope changes.  super(13)C enrichments of up to 3-4 ppt may occur at the sediment-water boundary layer. These isotopic changes are attributed to high benthic respiration rates.
AN: 2736114

                                                                    985 of 1521  
TI: Factors controlling the development of phytoplankton blooms in the Antarctic Ocean -- a mathematical model.
AU: Sakshaug,-E.; Slagstad,-D.; Holm-Hansen,-O.
AF: Trondhjem Biol. Stn., Univ. Trondheim, Museum, Bynesveien 46, N-7018 Trondheim, Norway
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 259-271
LA: English
ER: M (Marine)
AB: A mathematical model describing the development of phytoplankton blooms as a function of the depth of the wind-mixed layer, spectral distribution of light, passage of atmospheric low-pressure systems, size of the initial phytoplankton stock and loss rates is presented. Model runs represent shade-adapted, large-celled, bloom-forming diatoms. Periodic deep mixing caused by strong winds may severely retard the development of blooms and frequently abort them before macronutrients are completely exhausted. Complete exhaustion of macronutrients in the upper waters is likely only if the wind-mixed layer is < 10 m deep. Phytoplankton biomass may be controlled by iron in ice-free, deep-sea parts of the Antarctic Ocean, but the implied enhancement of export production through addition of iron might be restricted because of limitation by light, i.e. vertical mixing.
AN: 2735809

                                                                    986 of 1521  
TI: Nutrient distributions and new production in polar regions: Parallels and contrasts between the Arctic and Antarctic.
AU: Smith,-W.O.,Jr.
AF: Bot. Dep. and Grad. Prog. Ecol., Univ. Tennessee, Knoxville, TN 37996, USA
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 245-257
LA: English
ER: M (Marine)
AB: This paper discusses the influences of nitrate and ammonium concentrations on nitrate uptake (and hence new production), particularly with regard to data collected within marginal ice zones in the Arctic and Antarctic. Subsurface ammonium maxima in waters over 150 m are frequently encountered in the Arctic and occasionally in the Antarctic. Such maxima result from the heterotrophic remineralization of organic matter, and because stratified environments occur more frequently in the Arctic, significant concentrations of ammonium accumulate as a result of lower diffusive losses. Bacteria vs. zooplankton may also be different in the Arctic. Elevated ammonium concentrations significantly reduce nitrate uptake, and it is suggested that this nutrient interaction may play a significant role in controlling new production, particularly in open water regions.
AN: 2735791

                                                                    987 of 1521  
TI:  delta  super(13)C and  delta  super(15)N Variations in Weddell Sea particulate organic matter.
AU: Rau,-G.H.; Sullivan,-C.W.; Gordon,-L.I.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 355-369
LA: English
ER: M (Marine)
AB: The  delta  super(13)C and  delta  super(15)N of particulate organic matter (POM) sampled from the Weddell Sea in 1986 and 1988 ranged from -30.4 to -16.7 ppt and from -5.4 to +41.3 ppt, respectively. These large variations in POM  delta  super(13)C and  delta  super(15)N may reflect spatial/temporal changes in the concentrations and isotope abundances of CO sub(2)(aq.) and NH super(+)@)d4, respectively. Elevated isotope values were found exclusively in POM in or closely associated with sea ice, which may be the source of the  super(13)C- and  super(15)N-enriched sediments observed in this region.
AN: 2735762

                                                                    988 of 1521  
TI: Scavenging and particle flux: Seasonal and regional variations in the Southern Ocean (Atlantic sector).
AU: Rutgers-van-der-Loeff,-M.M.; Berger,-G.W.
AF: Alfred Wegener Inst. Polar and Mar. Res., Columbusst., D-2850 Bremerhaven, FRG
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 553-567
LA: English
ER: M (Marine)
AB: Even with large variations in flux rates, the scavenging of Pb and Th remains closely coupled to particle flux. In the Bransfield Strait, > 95% of the scavenging of  super(230)Th and  super(210)Pb occurs in two productive months, followed by negligible fluxes in winter. In winter, total  super(234)Th reaches equilibrium with its parent  super(238)U. During the bloom period, it is rapidly adsorbed onto particles and removed from the surface water. Notwithstanding the short production period, the annual fluxes of  super(230)Th and  super(210)Pb exceed their respective production rates in the water column by 60%.  super(210)Pb inventories in the sediment reflect the distribution of average present-day particle flux: high inventories occur in a zone just south of the Polar Front, including the Bransfield Strait and Drake Passage; low inventories are found north of the Polar Front and in the Weddell Sea, with minimum values in the central Weddell Gyre. A general relationship between radionuclide fluxes and particle rain rates as a tool for hindcasting palaeoproductivities cannot be given.
AN: 2735651

                                                                    989 of 1521  
TI: The production of biogenic silica in the Weddell and Scotia seas.
AU: Queguiner,-B.; Treguer,-P.; Nelson,-D.M.
AF: Lab. Chim. Ecosyst. Mar., Inst. Etud. Mar., Univ. Bretagne Occidentale, F-29287 Brest Cedex, France
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 449-459
LA: English
ER: M (Marine)
AB: During the EPOS leg 2 cruise, the production rate of biogenic silica in the euphotic zone was measured by the  super(30)Si method at stations in the Scotia and Weddell Seas. The highest integrated production rates were observed in the Scotia Sea, the marginal ice zone of the Weddell Sea exhibiting somewhat lower values. Results demonstrate that as far as biogenic silica production is concerned the marginal ice zone of the Weddell Sea is considerably less productive than that of the Ross Sea. The results also indicate that the water of the Antarctic Circumpolar Current (ACC) could be more productive in late spring and early summer than at the beginning of spring. Possible reasons for the differences among the three subsystems (Ross Sea, Weddell Sea and ACC) are discussed.
AN: 2735257

                                                                    990 of 1521  
TI: Barite formation in the Southern Ocean water column.
AU: Stroobants,-N.; Dehairs,-F.; Goeyens,-L.; Vanderheijden,-N.; Grieken,-R.-van
AF: Vrije Univ. Brussel, Anal. Chem. (ANCH), Pleinlaan 2, B-1050 Brussels, Belgium
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 411-421
LA: English
ER: M (Marine)
AB: The intensity of past biological activity can be correlated with the occurrence of suspended and sedimented barite (BaSO sub(4)). Vertical profiles of particulate barium generally show a Ba maximum between 200 and 500 m. SEM-EMP investigations on Scotia-Weddell Sea Confluence profiles provide a possible explanation for the origin of this subsurface Ba maximum. In the surface waters (i.e. above 200 m) barite is mainly contained within large bioaggregates. In the first 10-20 m of the water column the barite particles in the bioaggregates appear as amorphous entities without a clear crystalline habit. Below this surface layer barite in bioaggregates is present as microparticles with a crystalline habit. Below the first few hundred meters, barite crystals occur as free discrete particles. This suggests that in the subsurface zone (below 200 m) the "aggregates" are dispersed, possibly as a result of bacterial activity on the organic matrix, thereby releasing the individual barite crystals. Data suggest active precipitation by the living phytoplankton cell (i.e intravacuolar barite formation), as already observed by others for cultures of marine algae (Pavlovales).
AN: 2735163

                                                                    991 of 1521  
TI: Suspended barite as a tracer of biological activity in the Southern Ocean.
AU: Dehairs,-F.; Stroobants,-N.; Goeyens,-L.
AF: Vrije Univ. Brussel, ANCH, Pleinlaan 2, B-1050 Brussels, Belgium
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 399-410
LA: English
ER: M (Marine)
AB: During two cruises in the Southern Ocean (INDIGO 3, Indian sector and EPOS 2, Scotia-Weddell Confluence) suspended matter samples were collected for analysis of several biogenic elements including Ba, Si and particulate organic carbon (POC). The good agreement between particulate barium in subsurface water with oxygen minimum concentrations as well as with nitrate depletions suggests that it reflects the intensity of new production over the past season. As a consequence of new production in the Southern Ocean being performed mainly by diatoms, the occurrences of barite and diatoms are related in the water column. In areas characterized by diatom-poor phytoplankton, barite does occur, but in lower concentrations.
AN: 2735138

                                                                    992 of 1521  
TI: The dynamics of CO sub(2) fixation in the Southern Ocean as indicated by carboxylase activities and organic carbon isotopic ratios.
AU: Fontugne,-M.; Descolas-Gros,-C.; Billy,-G.-de
AF: Cent. Faibles Radioactiv., Lab. Mixte CNRS/CEA, Domaine du CNRS, 91 198 Gif sur Yvette, France
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 371-380
LA: English
ER: M (Marine)
AB: The authors present results from three cruises in the Indian and Atlantic sectors of the Southern Ocean (between 40 and 66 degree S) in which biochemical and physiological factors associated with photosynthetic processes lead to carbon isotopic fractionation by phytoplankton which cannot be directly related to variations within the mineral carbon pool. Simultaneous measurements of the carboxylase activities and the  super(13)C/ super(12)C ratio of particulate organic carbon show that there is a large variability in phytoplankton carbon metabolism, especially on a seasonal scale, in spite of a relative uniformity of the environmental conditions. Phytoplankton carbon metabolism is clearly a main factor governing variations in the stable isotopic composition of organic matter in the euphotic layer. Interrelationships between light, Rubisco activity and  delta  super(13)C are clearly shown. Heterotrophic processes also may influence the carbon isotope mass balance, especially during the break-up of the ice pack. The effect of the meridional temperature gradient is also verified.
AN: 2735095

                                                                    993 of 1521  
TI: Variations in phytoplanktonic nitrogen assimilation around South Georgia and in the Bransfield Strait (Southern Ocean).
AU: Owens,-N.J.P.; Priddle,-J.; Whitehouse,-M.J.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth PL1 3DH, UK
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 287-304
LA: English
ER: M (Marine)
AB: Nitrogen assimilation was measured in two austral summers in the Scotia Sea around the island of South Georgia and in the Bransfield Strait. Nitrate and ammonium assimilation was measured using  super(15)N techniques and the population was divided into two size classes, less than and greater than 20  mu m. The highest assimilation rate was found at a station near South Georgia, where the chlorophyll standing stock was elevated. A high assimilation rate was observed at a station in the Bransfield Strait and was associated with a localised, shallow mixed-layer feature. The less than 20  mu m size fraction contributed to a variable but frequently significant proportion of the total assimilation (14-78%). f ratios were generally low, signifying a high dependence of the population on ammonium as a nitrogen source.
AN: 2735071

                                                                    994 of 1521  
TI: Reconciling aggregation theory with observed vertical fluxes following phytoplankton blooms.
AU: Hill,-P.S.
AF: Sch. Oceanogr. WB-10, Univ. Washington, Seattle, WA, 98195, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C2, pp. 2295-2308
LA: English
ER: M (Marine)
AB: Sediment trap data show that rapidly sinking pulses of phytodetritus form after phytoplankton blooms, even when bloom intensity is low. A numerical model of physical aggregation and sedimentation in the surface ocean was used to gauge whether predicted aggregation rates were high enough to generate postbloom sediment pulses. Initial models behaved inaccurately without a full range of particle sizes, abundant nonphytoplankton particles, and explicit hydrodynamic retardation of particle contact. Provision for background particles while tracking phytoplankton required implementation of a novel bookkeeping scheme. To address the degree of retardation for contact between particles, an expression for contact efficiency for collision by turbulent shear was developed. The most realistic way to produce model results that mimicked field data was to include background particles, to invoke particle stickiness in the range 0.1-1.0, and to make modest upward adjustments to contact efficiencies calculated for impermeable spheres.
AN: 2735040

                                                                    995 of 1521  
TI: Evolution of Pb, Zn, Cu, Ni and As in Arcachon Lagoon (France). Influence of vegetal biomass on the geochemistry of lagoonal environment.
OT: Evolution du Pb, Zn, Cu, Ni et As dans le Bassin d'Arcachon (France). Impact de la biomasse vegetale sur la geochimie d'un environment lagunaire
AU: Lapaquellerie,-Y.; Latouche,-C.; Maillet,-N.; Dumon,-J.-C.; Carruesco,-C.
AF: Cent. Rech. Environ. Sed. Oceaniq., URA 197, Univ. Bordeaux 1, 351 Cours de la Liberation, 33405 Talence, France
SO: J.-MAR.-SYST. 1992. vol. 3, no. 1-2, pp. 19-30
LA: French
ER: M (Marine)
AB: The concentration of metals as Pb, Cu, Ni and As in suspended matters and sediments during 14 years shows for suspended matters and sediments that: Zn and Cu are increasing, Pb and As decreasing and Ni is stabilised. The evolution of the suspended matter can be explained by the quantitative evolution of algae and phanerogams during these last 14 years. The biomass evolution, which resulted in environmental nutrient contribution, intensifies the exchange factors of Pb and As in the lagoon. These remarks, beyond their local interests, provide notions of sedimentary environment model opposed to a polluting environment constituted by nautic tourism and a large area of monoculture (corn).
AN: 2733880

                                                                    996 of 1521  
TI: The relative importance of biotic and abiotic vectors in nutrient transport.
AU: Bildstein,-K.L.; Blood,-E.; Frederick,-P.
AF: Dep. Biol., Winthrop Coll., Rock Hill, SC 29733, USA
SO: ESTUARIES. 1992. vol. 15, no. 2, pp. 147-157
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The mass of nutrients (nitrogen, phosphorus, potassium, and calcium) imported during 1984 and 1985 to the North Inlet Estuary, Georgetown County, South Carolina, by precipitation and runoff was compared with that imported by a colonial-nesting wading bird, the white ibis (Eudocimus albus ). From late March through late June of both years, breeding ibises imported nutrients to the North Inlet Estuary study site from freshwater bottomland forest swamps, where they fed on crayfishes (Procambaridae). Although 1984 was a relatively wet year, in 1985 the ibis breeding season was preceded by a severe winter-spring drought. In 1984 ibises nested in higher numbers, had higher per-pair breeding success, and imported 11 times more nutrients than in 1985. Nutrient input from atmospheric sources was substantially lower in 1984 than in 1985. Our results show that nutrient inputs to estuaries from colonial-nesting wading birds can be substantial when compared with those from atmospheric sources and can vary considerably among years. They also suggest that nutrient regimes in estuaries with large assemblages of wading birds may differ significantly from those lacking such colonies.
AN: 2733555

                                                                    997 of 1521  
TI: Biochemical oxidation of organic matter in Bay of Bengal waters of Madras-Visakhapatnam.
AU: Loganathan,-B.; Venugopalan,-V.K.
AF: Cent. Adv. Stud. Mar. Biol., Annamalai Univ., Porto Novo 608 502, India
SO: INDIAN-J.-MAR.-SCI. 1984. vol. 13, no. 4, pp. 184-186
LA: English
ER: M (Marine)
AB: Water samples from 15 fixed stations in coastal and offshore regions in Bengal Bay were analysed for total non-specific organic matter through biochemical oxygen demand (BOD) analysis. BOD values varied between stations, depending on the nature and amount of organic matter decomposed by heterotrophic bacteria. The velocity rate (K) of destruction of organic matter and the ultimate BOD (L) of I stage were calculated using unimolecular equations. The computed rate constants help to predict the biochemical oxidation process involved and to asses the degree of population and self-purification capacity of polluted waters. K and L values of the station studied are quite comparable to the K and L values of other oceans reported earlier.
AN: 2733203

                                                                    998 of 1521  
TI: Nutrient cycling and fluxes associated with coastal regions adjacent to the Mississippi River.
AU: Twilley,-R.R.
AF: Univ. Southwestern Louisiana, Lafayette, LA 70501, USA
CO: 156. Natl. Meet. of the American Assoc. for the Advancement of Science, New Orleans, LA (USA), 15-20 Feb 1990
SO: 1990-AAAS-ANNUAL-MEETING-ABSTRACTS. Games,-M.D.-comp. 1989. p. 76
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Nutrient regeneration will be compared between two distributaries of the Mississippi River that discharge sediment and nutrients to coastal region of Louisiana: the Atchafalaya River empties into shallow bays while Southwest Pass flows into continental shelf. Stations included water depths of 1-2 m in the upper and lower sections of the Bay to 20-80 m on the continental shelf, during periods of high and low river flow. Respiration rates during the spring were similar among all stations at about 1.9 mmols m super(-2) h super(-1). Sediment regeneration rates for ammonium and silicate in both estuaries were generally higher near river input or in regions of highest water column productivity. Nitrate uptake generally occurred during the spring near freshwater; whereas nitrate and nitrite regeneration occurred at rates up to 80 umols m h in more saline environments. Phosphorus regeneration was less than 25 umols at all stations; lower rates occurred with elevated sediment redox. Water column regeneration was highest in areas with high levels of chlorophyll.
AN: 2731798

                                                                    999 of 1521  
TI: Estuarine modulation of nutrient transport from land to sea: Retention, assimilation and export.
AU: Kemp,-W.M.; Malone,-T.C.; Boicourt,-W.C.; Boynton,-W.R.; et-al.
AF: Univ. Maryland, CEES, Cambridge, MD, USA
CO: 156. Natl. Meet. of the American Assoc. for the Advancement of Science, New Orleans, LA (USA), 15-20 Feb 1990
SO: 1990-AAAS-ANNUAL-MEETING-ABSTRACTS. Games,-M.D.-comp. 1989. p. 76
NT: Abstract only.
LA: English
ER: B (Brackish); F (Freshwater)
AB: A hypothesis is developed and supporting evidence is presented to explain how physical and ecological mechanisms can allow estuaries, such as Chesapeake Bay, to retain, utilize and recycle nutrient inputs from the watershed in the short run while eventually exporting them to the sea. Time-series data indicate that planktonic and benthic community processes exhibit clear responses to seasonal and interannual variations in nitrogen inputs (mostly as NO sub(3) super(-)). However, preliminary mass balance calculations and short-term flux calculations at the bay mouth suggest that a large fraction of this N loading is exported to the continental shelf, largely in relatively refractory forms of DON. Thus, while the estuary is non-retentive with respect to N in a quantitative sense, it may nonetheless act as an efficient filter for the qualitative aspects of these N resources.
AN: 2731774

                                                                   1000 of 1521  
TI: Cyanobacterial precipitation of gypsum, calcite, and magnesite from natural alkaline lake water.
AU: Thompson,-J.B.; Ferris,-F.G.
AF: Dep. Microbiol., Univ. Guelph, Guelph, Ont., Canada
SO: GEOLOGY. 1990. vol. 18, no. 10, pp. 995-998
LA: English
ER: F (Freshwater)
AB: Results from transmission electron microscopy provide direct evidence for cyanobacterial biomineralization of gypsum and calcite in aquatic environments. Laboratory simulations using filter-sterilized natural lake water inoculated with Synechococcus  sp., isolated from Fayetteville Green Lake, New York, revealed epicellular biomineralization of gypsum, calcite, and magnesite. Experimental, electron microscopical, and sedimentological evidence indicates that Synechococcus  is responsible for a major proportion of the marl sediment and carbonate bioherms in Green Lake.
AN: 2731233

                                                                   1001 of 1521  
TI: GEOSECS Pacific and Indian Ocean  super(32)Si profiles.
AU: Somayajulu,-B.L.K.; Rengarajan,-R.; Lal,-D.; Craig,-H.
AF: Phys. Res. Lab., Ahmedabad 380 009, India
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 107, no. 1, pp. 197-216
LA: English
ER: M (Marine)
AB: Results of measurements of twelve  super(32)Si vertical profiles, nine from the Pacific Ocean at latitudes 45 degree N-58 degree S, and three from the Indian Ocean between the Equator and 38 degree S are presented. The amounts of in-situ extracted SiO sub(2) range from  similar to 1 to 25 g. The volumes of water from which dissolved silicon was extracted range from 200 to 9 x 10 super(5) kg. The net  super(32)P activities range from 0.7 to 3.8 cph. It is possible to measure accurately  super(32)Si ( super(32)P) activities as low as 2 x 10 super(-2) dpm from 25 g SiO sub(2) with the present techniques. The  super(32)Si concentrations in water range from 0.1 dpm/10 super(6) kg seawater to 178 dpm/10 super(6) kg seawater. The overall pattern of  super(32)Si increase with depth in the oceans resembles that of Si but the two differ appreciably; the enrichment of the former is controlled by its relatively short half-life.
AN: 2730049

                                                                   1002 of 1521  
TI: Fluxes of  super(226)Ra and barium in the Pacific Ocean: The importance of boundary processes.
AU: Moore,-W.S.; Dymond,-J.
AF: Dep. Geol. Sci., Univ. South Carolina, Columbia, SC 29208, USA
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 107, no. 1, pp. 55-68
LA: English
ER: M (Marine)
AB: The  super(226)Ra/Ba ratio in particles collected in sediment traps decreases with depth. Fluxes of Ba and Al increase with depth. These observations cannot be explained by simple vertical processes. Instead they require a component to the deep flux which originates at the ocean margins. We suggest that the deep traps are enriched in Ba through the advection of barite originally precipitated in biologically productive regions of the ocean margin. This source is less important for  super(226)Ra because some is lost by radioactive decay between the precipitation of barite on the margin and outward transport. The boundary flux is an important source of material to the deep sea. From  super(226)Ra fluxes in the upper 1000 m of the water column, we estimate that the residence time of  super(226)Ra in the upper ocean is 400 years. The removal of  super(226)Ra in the particle flux is approximately balanced by the upwelling of waters enriched in  super(226)Ra.
AN: 2729170

                                                                   1003 of 1521  
TI: Evolutionary trends in the lipid biomarker approach for investigating the biogeochemistry of organic matter in the marine environment.
AU: Saliot,-A.; Laureillard,-J.; Scribe,-P.; Sicre,-M.A.; Branica,-M.
AF: Lab. Phys. et Chim. Mar., Univ. Pierre et Marie Curie, UA, CNRS No. 353, 4 place Jussieu, 75252 Paris Cedex 05, France
CO: 11. Int. Symp. on Chemistry of the Mediterranean, Primosten (Croatia), 9-16 May 1990
SO: REACTIVITY-OF-CHEMICAL-SPECIES-IN-AQUATIC-ENVIRONMENTS. Kniewald,-G.-ed. 1991. vol. 36, no. 1-4 pp. 233-248
ST: MAR.-CHEM. vol. 36, no. 1-4
LA: English
ER: M (Marine)
AB: The detailed investigation of organic carbon cycling in estuarine and marine environments has stimulated the development of multidisciplinary concepts, research and sampling strategies as well as analytical tools in the last 10 years. Although some limitations exist for the elucidation of their stereochemistry, sterols have been used extensively to study biochemical processes affecting the organic matter in the water column and at the ocean/sediment interface. Sterols also appear as promising tracers of terrestrial vs. marine inputs in complex estuarine systems. The specificity of individual fatty acids or groups of acids has also been used to assess the origins and transformation processes of organic matter in marine samples. New approaches are presented including the investigation of intact lipid classes and the elucidation of the position of double bonds of unsaturated fatty acids and alkenes. Finally, we discuss the use of chemometric techniques due to increasing chemical information and the interest of combining molecular-level and stable isotope approaches.
AN: 2726662

                                                                   1004 of 1521  
TI: Dissolved trace element cycles in the San Francisco Bay estuary.
AU: Flegal,-A.R.; Smith,-G.J.; Gill,-G.A.; Sanudo-Wilhelmy,-S.; Anderson,-L.C.D.; Branica,-M.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
CO: 11. Int. Symp. on Chemistry of the Mediterranean, Primosten (Croatia), 9-16 May 1990
SO: REACTIVITY-OF-CHEMICAL-SPECIES-IN-AQUATIC-ENVIRONMENTS. Kniewald,-G.-eds. 1991. vol. 36, no. 1-4 pp. 329-363
ST: MAR.-CHEM. vol. 36, no. 1-4
LA: English
ER: B (Brackish)
AB: Dissolved trace element (copper, nickel, cadmium, zinc, cobalt, and iron) concentrations were measured in surface water samples collected from 27 stations in the San Francisco Bay and Sacramento-San Joaquin Delta during Apr., Aug. and Dec. 1989. The trace element distributions were relatively similar for all three sampling periods, and evidenced two distinct biogeochemical regimes within the estuarine system. The two regimens were comprised of relatively typical trace element gradients in the northern reach and anthropogenically perturbed gradients in the southern reach of the estuary. These dichotomous trace element distributions were consistent with previous reports on the distributions of nutrients and some other constituents within the estuary.
AN: 2726611

                                                                   1005 of 1521  
TI: Evolution of dissolved and particulate matter during the ice-covered period in a deep, high-mountain lake.
AU: Catalan,-J.
AF: Dep. Ecol., Univ. Barcelona, Diagonal 645, 08028 Barcelona, Spain
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1992. vol. 49, no. 5, pp. 945-955
NT: Incl. bibliogr.: 60 ref.
LA: English
ER: F (Freshwater)
AB: Changes in inorganic and organic matter beneath the ice in a deep oligotrophic lake are used to establish temporal and spatial scales of physical and biological processes involved in the dynamics of the system during low energy flow.
AN: 2725795

                                                                   1006 of 1521  
TI: Atmospheric cycling and air-water exchange of mercury over mid-continental lacustrine regions.
AU: Fitzgerald,-W.F.; Mason,-R.P.; Vandal,-G.M.
AF: Dep. Mar. Sci., Univ. Connecticut, Groton, CT 06340, USA
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 745-767
LA: English
ER: F (Freshwater)
AB: Atmospheric mobilization and exchange at the air-water interface are significant features of biogeochemical cycling of Hg at the Earth's surface. Our marine studies of Hg have been extended to inland aquatic systems, where we are investigating the tropospheric cycling, deposition and air-water exchange of Hg in the mid-continental lacustrine environs of north central Wisconsin. This program is part of a multidisciplinary examination into the processes regulating the aquatic biogeochemistry of Hg in temperate regions. Trace-metal-free methodologies are employed to determine Hg and and alkylated Hg species at the picomolar level in air, water and precipitation.
AN: 2721576

                                                                   1007 of 1521  
TI: Copper complexes with the porphyrin system in sediments of the Baltic Sea.
AU: Kowalewska,-G.
AF: Inst. Oceanol., Polish Acad. Sci., ul. Powstancow Warszawy 55, 81-967 Sopot, Poland
SO: POL.-ARCH.-HYDROBIOL.-POL.-ARCH.-HYDROBIOL. 1990. vol. 37, no. 3, pp. 327-339
LA: English
ER: M (Marine)
AB: Extracts of bottom sediments from the Baltic Sea were studied for possible occurrence of copper complexes with the porphyrin system. A correlation between copper content and porphyrin-type compounds in HPLC chromatograms of the extracts has been found. Copper content was usually highest in extracts of the surface layer, which indicated contemporary formation and accumulation of the compounds. The observed correlation of the porphyrin compounds with carotenes let us suppose that copper is involved in a biogeochemical cycle, entering the porphyrin ring of chlorophyll and being released in sediments, especially under anoxic conditions.
AN: 2720372

                                                                   1008 of 1521  
TI: Interhemispheric transport of carbon dioxide by ocean circulation.
AU: Broecker,-W.S.; Peng,-Tsung-Hung
AF: Lamont-Doherty Geol. Obs., Columbia Univ., Palisades, NY 10964, USA
SO: NATURE. 1992. vol. 356, no. 6370, pp. 587-589
LA: English
AB: Before the Industrial Revolution, natural CO sub(2) sources and sinks acted to set up a south to north gradient which drove about one gigatonne of carbon each year through the atmosphere from the Southern to the Northern Hemisphere. At steady state, this flux must have been balanced by a counter flow of carbon from north to south through the ocean. Here we present a means to estimate this natural flux by a separation of oceanic carbon anomalies into those created by biogenic processes and those created by CO sub(2) exchange between the ocean and atmosphere. Deep water formed in the northern Atlantic Ocean carried about 0.6 gigatonnes of carbon annually to the Southern Hemisphere, providing support for Keeling and Heimann's proposal. The existence of this oceanic carbon pump also raises questions about the need for a large terrestrial carbon sink in the Northern Hemisphere to balance the present global carbon budget.
AN: 2718697

                                                                   1009 of 1521  
TI: Feeding and assimilation of mangrove leaves by the crab Sesarma meinerti  de Man in relation to leaf-litter production in Mgazana, a warm-temperate southern African mangrove swamp.
AU: Emmerson,-W.D.; McGwynne,-L.E.
AF: Dep. Zool., Univ. Transkei, P Bay X1, Umtata, Transkei, South Africa
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1992. vol. 157, no. 1, pp. 41-53
LA: English
ER: M (Marine)
AB: Consumption of Avicennia marina  leaves by the large detritivorous mangrove grapsid Sesarma meinerti  was measured in the laboratory. This was compared with abscission rates for this mangrove species in the field (Mgazana estuary, Transkei, southern Africa) to estimate how much leaf material was directly utilised by this ecologically dominant crab. Although a significant correlation was found between crab size and dry litter mass ingested per day, no correlation was found between crab size and assimilation efficiency, which was high (82.44%). A seasonal trend in leaf litter fall was discernable with a mean annual rate of 1.79 g m super(-2)/d (653.4 g m super(-2)/y). With a mean crab density of 4 m super(-2) and mean crab size of 40 g, leaf consumption was calculated at 0.78 g m super(-2)/d DM (284.7 g m super(-2)/y or 6462 kJ m super(-2)/y), accounting for 43.58% of the leaf fall. For the entire mangrove area (150 ha) a total of 75 t of frasse (955 kJ m super(-2)/y) enters the estuary per annum. This is a considerable contribution to the detrital pool of the estuary and increases leaf turnover an estimated four-fold.
AN: 2718026

                                                                   1010 of 1521  
TI: Oceanic biogeochemical processes: The importance of biology.
AU: Fowler,-S.
AF: Int. Lab. Mar. Radioact., Monaco, Monaco
CA: Union des Oceanographes de France (France)
CO: 16. Colloq. de l'UOF (Union des Oceanographes de France), Roscoff (France), 7-8 Jun 1990
SO: PROCEEDINGS-OF-THE-16th-SYMPOSIUM-OF-UOF-1st-PART,-ROSCOFF-7-8-JUNE-1990..  ACTES-DU-16e-COLLOQUE-DE-L'-UOF-1ere-PARTIE,-ROSCOFF-7-8-JUIN-1990. 1991. vol. 16, no. 1-2 pp. 5-9
ST: J.-RECH.-OCEANOGR. vol. 16, no. 1-2
LA: English
ER: M (Marine)
AB: Element scavenging and removal, organic compound transformations and biogenic particle regeneration of materials are closely coupled to biological activity particularly in the epipelagic and mesopelagic zones where the bulk of oceanic biomass resides. The dynamics of these processes are further controlled by a variety of intrinsic and environmental factors. Recent evidence indicates that biogenic particles are highly enriched in many elements and compounds and thereby serve as important vectors in effecting the downward vertical flux of elements and their distributions in the water column. Analogous to nutrient regeneration cycles, certain elements and radionuclides incorporated in biogenic aggregates are remineralized as the particles sink and undergo decomposition. In contrast, for many particle-reactive elements, sinking biogenic particles scavenge metals and radionuclides and remove them from the surface layers. Recent evidence from in situ sediment trap studies is presented.
AN: 2717958

                                                                   1011 of 1521  
TI: Characterization of surface-active substances during a semi-field experiment on a phytoplankton bloom.
AU: Plavsic,-M.; Vojvodic,-V.; Cosovic,-B.
AF: Rudjer Boskovic Inst., Cent. Mar. Res. Zagreb, Bijenicka c. 54, 41001 Zagreb, Yugoslavia
SO: ANAL.-CHIM.-ACTA. 1990. vol. 232, no. 1, pp. 131-140
NT: Special issue: Humic and fulvic compounds.
LA: English
ER: M (Marine)
AB: The determination of surface-active substances (SAS) during the evolution of a phytoplankton bloom in a model plankton ecosystem was done by electrochemical methods. The separation and characterization of the organic material present were also done on XAD-8 resin columns. It was found that large amounts of the SAS, predominantly of the humic (fulvic) type, were present from the beginning of the experiment and partly masked the effects of organic substances released by phytoplankton. Although the transformation of the organic matter (consumption and/or excretion) was obvious, no general trend in the amount or type of surface-active matter was observed during the experiment.
AN: 2717849

                                                                   1012 of 1521  
TI: Metal-organic interactions in sea water: An ecosystem experiment.
AU: Mackey,-D.J.; O'-Sullivan,-J.E.
AF: CSIRO Div. Oceanogr., GPO Box 1538, Hobart, Tas. 7001, Australia
SO: ANAL.-CHIM.-ACTA. 1990. vol. 232, no. 1, pp. 161-170
NT: Special issue: Humic and fulvic compounds.
LA: English
ER: M (Marine)
AB: A model plankton ecosystem was used to study the interactions of trace metals and organic compounds over a 10-day period during a phytoplankton bloom. Six bags of 1200-l capacity were filled with coastal sea water. Three bags were spiked with copper (78, 157 and 314 nM) and one with copper (4.57  mu M) plus nitrilotriacetic acid (10  mu M). Organically bound complexes of copper (18% of the total), zinc (7%), nickel (4%) and iron (2%) were isolated by adsorption on Sep-Pak cartridges. The metal-organic complexes, were analysed on a liquid chromatograph interfaced to a multichannel atomic fluorescence detector. Organic complexes of zinc, iron and nickel were formed even in the presence of a large excess of copper.
AN: 2717814

                                                                   1013 of 1521  
TI: Ultrafiltration as a technique for studying metal-humate interactions: Studies with iron and copper.
AU: Ephraim,-J.H.; Marinsky,-J.A.
AF: Dep. Water and Environ. Stud., Linkoeping  Univ., S-581 83 Linkoeping, Sweden
SO: ANAL.-CHIM.-ACTA. 1990. vol. 232, no. 1, pp. 171-180
NT: Special issue: Humic and fulvic compounds.
LA: English
ER: F (Freshwater)
AB: An ultrafiltration method was employed to study Fe(II)/Fe(III) and Cu(II) binding by Armadale Horizon fulvic acid. The results of the Fe-fulvate studies indicate the formation of "aggregates" between Fe and the fulvic acid molecule. The reduction of Fe(III) to Fe(II) by fulvic acid is also observed. Results for Cu(II)-fulvate interaction obtained by the ultrafiltration method are consistent with those obtained by the direct in situ ion-selective electrode method. An algorithm developed previously for the prediction of metal ion binding by fulvic acid at different pH and salt concentration levels was tested further by comparing Cu super(2+) ion binding predictions with their measured values.
AN: 2717795

                                                                   1014 of 1521  
TI: Modelling of interrelationships between climate, biosphere, and hydrological cycles.
AU: Mauersberger,-P.
AF: Akad. Wiss. DDR, Inst. Geogr. und Geooekol., Bereich Hydrol., Mueggelseedamm 260, Berlin DDR-1162, FRG
SO: GERLANDS-BEITR.-GEOPHYS. 1990. vol. 99, no. 2, pp. 157-161
LA: English
AB: It is recommended to apply generalized hydrothermodynamics and synergetics in combination with the analysis of historical data and recent observations for the investigation and modelling of interrelationships between climate, biosphere and hydrological cycles.
AN: 2716558

                                                                   1015 of 1521  
TI: Iodine abundances in oceanic basalts: Implications for Earth dynamics.
AU: Deruelle,-B.; Dreibus,-G.; Jambon,-A.
AF: Lab. Magmatol. Geochim. Inorgan. Exp., Unit Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris Cedex 05, France
SO: EARTH-PLANET.-SCI.-LETT. 1992. vol. 108, no. 4, pp. 217-227
LA: English
ER: M (Marine)
AN: 2713812

                                                                   1016 of 1521  
TI: Chitin biomass and production in the marine environment.
AU: Jeuniaux,-C.; Voss-Foucart,-M.F.
AF: Lab. Morphol., Syst. and Anim. Ecol., Univ. Liege, 22 quai Van Beneden, B-4020 Liege, Belgium
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 347-356
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The total production of chitin has been tentatively calculated on the basis of original analytical data on chitin in zooplankton and in benthic communities growing on experimental substrates studied in the Mediterranean Sea, together with data in the literature dealing with total and exuviae production by krill and by some large crustacean species. It appears that crustaceans are the main chitin producers both in planktonic and benthic ecosystems, and that mean total production of chitin in the whole marine biocycle is at least of 2.3 million metric tons per year.
AN: 2712994

                                                                   1017 of 1521  
TI: Mineralization of chitin in an estuarine sediment: The importance of the chitosan pathway.
AU: Gooday,-G.W.; Prosser,-J.I.; Hillman,-K.; Cross,-M.G.
AF: Dep. Mol. and Cell Biol., Univ. Aberdeen, Marischal Coll., Aberdeen AB9 1AS, UK
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 395-400
LA: English
ER: B (Brackish)
AB: In order to study the mineralization of chitinous material, pieces of squid pen chitin-protein in litter bags were exposed to a range of aquatic environments. Scanning electron microscopy showed that they were rapidly colonized by a wide variety of microbes. Populations within microhabitats, however, had a low species diversity, suggesting that cells colonizing initially could rapidly establish colonies. The squid pen was digested in all environments studied, but at rates that varied with season and habitat. Analyses of estuarine sediments of the River Ythan, Aberdeenshire showed appreciable levels of chitin and chitosan, and appreciable activities of chitinase and chitin deacetylase. These results suggest that two pathways are important in the mineralization of chitin in these sediments; one involving chitinases and N-acetylglucosamine, and another involving chitin deacetylase and chitosanase.
AN: 2712993

                                                                   1018 of 1521  
TI: Chitin dynamics in the freshwater environment.
AU: Miyamoto,-S.; Yamamoto,-H.; Seki,-H.
AF: Inst. Biol. Sci., Univ. Tsukuba, Tsukuba, Ibaraki 305, Japan
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 371-377
LA: English
ER: F (Freshwater)
AB: The seasonal fluctuation of chitin dynamics in fresh water was studied in a mesotrophic bog and a hypereutrophic lake in Japan. The metabolic rates of chitin were higher in more eutrophic water. Thus, the chitin turnover rate during summer was one order of magnitude greater in the hypereutrophic lake than in the mesotrophic bog. However, the steady-state oscillation of basal chitin stock averaged approximately 200 mg C/m super(2) in both ecosystems. The production rate of detrital chitin was higher than the decomposition rate in the mesotrophic bog.
AN: 2712977

                                                                   1019 of 1521  
TI: Chitin primary production.
AU: Smucker,-R.A.
AF: EPAC, P.O. Box 1269, Solomons, MD 20688, USA
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 357-369
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Previous perspectives of chitin's role in the biosphere have been deficient because the role of chitin in primary production has been overlooked. Reasons for this oversight include confusion of chitins with the putative protein precipitates forming upon 5% trichloroacetic acid treatment. The cellular biology of known phytoplankton chitin-producers is presented within the context of documented biochemistry and ultrastructure. Several biochemical strategies were used in substantiating the presence of chitin in primary products in in situ experiments. Alkali and sodium dodecylbenzenesulfonate solubilized proteins differentiate protein and chitin. The high values of chitin disclosed for primary production will require rethinking of analytical strategies previously used for biogeochemistry and physiological ecology especially with respect to carbohydrates. Primary production of chitin and chitan must now be considered within the phytoplankton taxa.
AN: 2712975

                                                                   1020 of 1521  
TI: Chitin biodegradation in marine environments: An experimental approach.
AU: Poulicek,-M.; Jeuniaux,-C.
AF: Zool. Inst., Liege Univ., 22 Quai Ed. van Beneden, B-4020 Liege, Belgium
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 385-394
LA: English
ER: M (Marine)
AB: Chitin biomasses and production in marine environments are quite high. Planktonic biocenoses are the main producers and one should expect that sediments, mainly organoclastic ones, will constitute some kind of reserve compartment for the biogeochemical cycle of this polymer. In fact, this is not the case. The low chitin biomass in most marine sediments can only be explained if chitin is weathered at the same rate as it is produced. In order to test this hypothesis, we developed an experimental approach to chitin biodegradation in marine environments. In open water conditions, zooplanktonic remains are first degraded by autolytic processes making most organic compounds readily susceptible for further hydrolysis by extrinsic decomposers. Different populations (with high densities and various hydrolytic potentials) follow each other. The sequence of hydrolytic activities optimizes the recycling of most detritic compounds including nearly 90% of the chitin produced.
AN: 2712952

                                                                   1021 of 1521  
TI: Geology and environmental change: A New Brunswick perspective.
AU: Pronk,-A.G.
AF: Geol. Surv. Branch, Min. Res. Div., Dep. Nat. Resour. Energy, P.O. Box 6000, Fredericton, N.B. E3B 5H1, Canada
SO: ATL.-GEOL. 1991. vol. 27, no. 2, pp. 97-106
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Studies of earth cycles are used in a variety of ways, from mineral exploration to recording and explaining past, and projecting future climate change. Geology helps us find the commodities we need to accommodate our lifestyles, to assess natural hazards, find drinking water and safe places to dispose of our waste. As mankind will search for a way to achieve a globally sustainable society, the limits of this planet will have to be acknowledged. Geology is one of the disciplines that can help us understand our planet and establish those limits. Further research in the earth sciences is required to clarify our present knowledge of the environment, quantify many processes, and define limits of prediction for future change.
AN: 2706084

                                                                   1022 of 1521  
TI: Crystal assembly and phologenetic evolution in heterococcoliths.
AU: Young,-J.R.; Didymus,-J.M.; Bown,-P.R.; Prins,-B.; Mann,-S.
AF: Palaeontol. Dep., Nat. Hist. Mus., Cromwell Rd., London SW7 5BD, UK
SO: NATURE. 1992. vol. 356, no. 6369, pp. 516-518
LA: English
ER: M (Marine)
AB: Coccoliths, the calcite plates formed by unicellular phytoplanktonic algae (coccolithophores, phylum Prymnesiophyta), are produced in enormous quantities and probably constitute the largest single carbonate sink in oceanic biogeochemical cycles. They are major sediment formers, are of great value to geologists as biostratigraphic indicators and have been extensively studied as models for biomineralization. We have applied the understanding of coccolith biomineralization to the fossil record and present evidence from electron and optical microscopy that there has been a conserved mechanism of crystal nucleation throughout the 230 million year history of coccolithophores. This fundamental feature of coccolith growth, which we term the V/R model, involves the assembly of a ring of single crystals with alternating orientations, radial (R) and vertical (V), and provides a powerful tool for tracing phylogenies, identifying homologous structures and rationalizing the higher taxonomy of the group. The living coccolithophorid, Emiliania huxleyi , seemed anomalous because only R crystals had been observed; transmission electron microscopy of proto-coccolith rings, however, evealed relict V crystals which are overgrown by preferential development of R units in complete coccoliths.
AN: 2704008

                                                                   1023 of 1521  
TI: Benthic organic carbon degradation and biogenic silica dissolution in the central Equatorial Pacific.
AU: Martin,-W.R.; Bender,-M.; Leinen,-M.; Orchardo,-J.
AF: Dep. Chem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 12A, pp. 1481-1516
LA: English
ER: M (Marine)
AB: Shipboard whole-core squeezing was used to measure pore water concentration vs depth profiles of NO super(-)@)d3, O sub(2) and SiO sub(2) at 12 stations in the equatorial Pacific along a transect from 15 degree S to 11 degree N at 135 degree W. The NO super(-)@)d3 and SiO sub(2) profiles were combined with fine-scale resistivity and porosity measurements to calculate benthic fluxes. After using O sub(2) profiles, coupled with the NO super(-)@)d3 profiles, to constrain the C:N of the degrading organic matter, the NO super(-)@)d3 fluxes were converted to benthic organic carbon degradation rates. The range in benthic organic carbon degradation rates is 7-30  mu mol cm super(-2)/y, with maximum values at the equator and minimum values at the southern end of the transect. The zonal trend of benthic degradation rates, with its equatorial maximum and with elevated values skewed to the north of the equator, is similar to the pattern of primary production observed in the region. Benthic organic carbon degradation is 1-2% of primary production. The range of benthic biogenic silica dissolution rates is 6.9-20  mu mol cm super(-2)/y, representing 2.5-5% of silicon fixation in the surface ocean of the region.
AN: 2702725

                                                                   1024 of 1521  
TI: The contribution of deep-sea macroplankton to organic remineralization: Results from sediment trap and zooplankton studies over the Madeira Abyssal Plain.
AU: Lampitt,-R.S.
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1992. vol. 39, no. 2A, pp. 221-233
LA: English
ER: M (Marine)
AB: At a subtropical deep-sea site of water depth 5440 m the flux of material entering and leaving a 900 m thick stratum 100 m above the seabed was measured using sediment traps. Differences between the organic carbon entering the stratum and that leaving was taken as a measure of the remineralization rate within it. At the same site the biomass of the net zooplankton was measured, and using published estimates of their respiratory requirements, their organic carbon demands were calculated. The results indicate that the zooplankton were responsible for about 9% of the remineralization occurring in that body of water but possibly much higher further up in the water column. The remainder is presumably carried out by those organisms too small, too fragile or too agile to be captured by the net. Although the zooplankton may not contribute greatly to organic carbon remineralization, they are likely to modify sinking and suspended particles in such a way as to have a significant effect on material flux.
AN: 2700982

                                                                   1025 of 1521  
TI: The distribution of dissolved vanadium in eastern Canadian coastal waters.
AU: Yeats,-P.A.
AF: Phys. and Chem. Sci., Dep. Fish. and Oceans, Bedford Inst. Oceanogr., P.O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
SO: ESTUAR.-COAST.-SHELF-SCI. 1992. vol. 34, no. 1, pp. 85-93
LA: English
AB: Dissolved vanadium measurements from the Gulf of St Lawrence and the Scotian shelf are reported. The Gulf of St Lawrence results reveal an average vanadium concentration of 24 nM in the deep water of the Gulf decreasing to 17 multiplied by 6 nM in the St Lawrence River. The Saguenay River had an even lower vanadium concentration of 5 multiplied by 1 nM. Linear increases in concentration with salinity were seen for both the St Lawrence estuary and the Saguenay fjord. In the Gulf of St Lawrence and on the Scotian shelf, depletion of vanadium in the surface waters and increasing concentrations with depth were observed. The vanadium-salinity relationships for these coastal waters both show increasing vanadium concentrations with increasing salinity and correlations that are indicative of extensive removal of dissolved vanadium from surface waters. In general, the distributions can be explained in terms of the strengths of the input functions, be they rivers, atmospheric precipitation or oceanic advection, and the removal by biogenic scavenging processes.
AN: 2699680

                                                                   1026 of 1521  
TI: Oceanic uptake of fossil fuel CO sub(2): Carbon-13 evidence.
AU: Quay,-P.D.; Tilbrook,-B.; Wong,-C.S.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: SCIENCE-WASH.. 1992. vol. 256, no. 5053, pp. 74-79
LA: English
ER: M (Marine)
AB: The  delta  super(13)C value of the dissolved inorganic carbon in the surface waters of the Pacific Ocean has decreased by about 0.4 per mil between 1970 and 1990. This decrease has resulted from the uptake of atmospheric CO sub(2) derived from fossil fuel combustion and deforestation. The net amounts of CO sub(2) taken up by the oceans and released from the biosphere between 1970 and 1990 have been determined from the changes in three measured values: the concentration of atmospheric CO sub(2), the  delta  super(13)C of atmospheric CO sub(2) and the  delta  super(13)C value of dissolved inorganic carbon in the ocean. The calculated average net oceanic CO sub(2) uptake is 2.1 gigatons of carbon per year. This amount implies that the ocean is the dominant net sink for anthropogenically produced CO sub(2) and that there has been no significant net CO sub(2) released from the biosphere during the last 20 years.
AN: 2698929

                                                                   1027 of 1521  
TI: Variations in the strontium isotopic composition of seawater during the Neogene.
AU: Hodell,-D.A.; Mueller,-P.A.; Garrido,-J.R.
AF: Dep. Geol., Univ. Florida, Gainesville, FL 32611, USA
SO: GEOLOGY. 1991. vol. 19, no. 1, pp. 24-27
LA: English
ER: M (Marine)
AB: The authors report 261 strontium isotopic analyses of well-preserved planktonic foraminifers from three Deep Sea Drilling Project Sites (519, 588, and 607). These samples cover the period from 24 Ma to present with an average of approximately one sample per 100 ka. The combination of high sample density and uniformity of analytical procedures has produced a well-defined record of changes in the  super(87)Sr/ super(86)Sr of seawater during the Neogene. The record can be viewed as a series of essentially linear segments with slopes ranging from as high as 6 x 10 super(-5)/m.y. to as low as 0/m.y. The times associated with major inflections in the curve do not appear to correspond to simple geologic phenomena such as eustatic cycles, but are probably controlled by a combination of tectonic and climatic factors that influenced the abundance and isotopic composition of terrestrial strontium input to the oceans. The strontium isotopic data are consistent with a progressive increase in the chemical weathering rates of the continents during the Neogene, probably related to repeated glaciations, increased exposure of continents by lowered sea level, and increased continental relief resulting from high rates of tectonic uplift.
AN: 2698565

                                                                   1028 of 1521  
TI: Revised budget for the oceanic uptake of anthropogenic carbon dioxide.
AU: Sarmiento,-J.L.; Sundquist,-E.T.
AF: Atmos. and Oceanic Sci. Program, Princeton Univ., Princeton, NJ 08544-0710, USA
SO: NATURE. 1992. vol. 356, no. 6370, pp. 589-593
LA: English
ER: M (Marine)
AB: Tracer-calibrated models of the total uptake of anthropogenic CO sub(2) by the world's oceans give estimates of about 2 gigatonnes carbon per year, significantly larger than a recent estimate of 0.3-0.8 Gt C/yr for the synoptic air-to-sea CO sub(2) influx. Although both estimates require that the global CO sub(2) budget must be balanced by a large unknown terrestrial sink, the latter estimate implies a much larger terrestrial sink, and challenges the ocean model calculations on which previous CO sub(2) budgets were based. The discrepancy is due in part to the net flux of carbon to the ocean by rivers and rain, which must be added to the synoptic air-to-sea CO sub(2) flux to obtain the total oceanic uptake of anthropogenic CO sub(2). Here we estimate the magnitude of this correction and of several other recently proposed adjustments to the synoptic air-sea CO sub(2) exchange. These combined adjustments minimize the apparent inconsistency, and restore estimates of the terrestrial sink to values implied by the modelled oceanic uptake.
AN: 2698558

                                                                   1029 of 1521  
TI: Measurement of marine picoplankton cell size by using a cooled, charge-coupled device camera with image-analyzed fluorescence microscopy.
AU: Viles,-C.L.; Sieracki,-M.E.
AF: Bigelow Lab. Ocean Sci., McKown Point, West Boothbay Harbor, ME 04575, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1992. vol. 58, no. 2, pp. 584-592
LA: English
ER: M (Marine)
AB: Accurate measurement of the biomass and size distribution of picoplankton cells (0.2 to 2.0  mu m) is paramount in characterizing their contribution to the oceanic food web and global biogeochemical cycling. Image-analyzed fluorescence microscopy, usually based on video camera technology, allows detailed measurements of individual cells to be taken. The application of an imaging system employing a cooled, slow-scan charge-coupled device (CCD) camera to automated counting and sizing of individual picoplankton cells from natural marine samples is described. A slow-scan CCD-based camera was compared to a video camera and was superior for detecting and sizing very small, dim particles such as fluorochrome-stained bacteria. Several edge detection methods for accurately measuring picoplankton cells were evaluated. Standard fluorescent microspheres and a Sargasso Sea surface water picoplankton population were used in the evaluation.
AN: 2697721

                                                                   1030 of 1521  
TI: Degradation of plant litter by aquatic hyphomycetes.
AU: Hasija,-S.K.; Singhal,-P.K.
AF: Dep. Biol. Sci., Rani Durgavati Univ., Jabalpur, India
SO: HANDBOOK-OF-APPLIED-MYCOLOGY.-SOIL-AND-PLANTS. Arora,-D.K.;Rai,-B.;Mukerji,-K.G.;Knudsen,-G.R.-eds. 1991. vol. 1, pp. 481-505
LA: English
AB: The present review discusses the mode of fungal transformation of litter into an important energy source for the detritus food chain in freshwater environments.
AN: 2697540

                                                                   1031 of 1521  
TI: Naturally and anthropogenically produced bromoform in the Kattegatt, a semi-enclosed oceanic basin.
AU: Fogelqvist,-E.; Krysell,-M.
AF: Swed. Meteorol. Hydrol. Inst., Oceanogr. Lab., P.O. Box 2212, S-403 14 Goeteborg, Sweden
SO: J.-ATMOS.-CHEM. 1991. vol. 13, no. 4, pp. 315-324
LA: English
ER: M (Marine)
AB: The origin of bromoform in seawater and atmosphere, as well as possible sinks and breakdown mechanisms, is discussed. A bromoform budget is calculated for the Kattegatt area between Sweden and Denmark, where the input of bromoform from a power plant is significant. Both anthropogenically (250 x 10 super(6) g yr super(-1)) and biogenically (350 x 10 super(6) g yr super(-1), 0.016 g m super(-2) yr super(-1)) produced bromoform is likely to have a great impact locally on the inventory and the release to the atmosphere. Using measured surface concentrations of bromoform, the total annual release from the Kattegatt to the atmosphere is estimated to 550 x 10 super(6) g (0.025 g m super(-2) yr super(-1)).
AN: 2696732

                                                                   1032 of 1521  
TI: Elemental cycling and fluxes off Southern California.
AU: Muench,-R.D.
AF: SAIC, 13400B Northrup Way, Suite 36, Bellevue, WA 98005, USA
SO: EOS.-TRANS.-AM.-GEOPHYS.-UNION. 1989. vol. 70, no. 10, pp. 146-148
LA: English
ER: M (Marine)
AN: 2695849

                                                                   1033 of 1521  
TI: N sub(2)O concentrations in the water and gas phase of the tidal Elbe and the German Bight.
OT: N sub(2)O-Gehalte in Wasser- und Luftproben aus den Bereichen der Tideelbe und der Deutschen Bucht
AU: Hanke,-V.-R.; Knauth,-H.-D.
AF: GKSS-Forschungszentr. Geesthacht, Max-Planck-Str., D-W 2054 Geesthacht, FRG
SO: VOM-WASSER. 1990. vol. 75, pp. 357-374
NT: Bibliogr.: 22 ref. Received Feb 1992.
LA: German
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Measurements of the distribution of N sub(2)O and to a lesser degree NH sub(4)@)u+, NO sub(3)@)u- and NO sub(2)@)u- in the river Elbe and the German Bight were carried out by analysis of samples from the gas and water phases. The aim of this work was to acquire additional information on the biogeochemistry of the nitrogen cycle in the riverine system. For the determination of N sub(2)O, a suitable method of analysis had to be developed. The results obtained show that the Elbe sediments are an effective source of N sub(2)O. The supersaturation factors for N sub(2)O in the water phase and local concentration increases of the N sub(2)O in the gas phase, when compared to the mean atmospheric value of 330 nl/l, indicate that most of the N sub(2)O gas produced by nitrification and in particular denitrification processes in the Elbe estuarine system is released into the atmosphere.
AN: 2693211

                                                                   1034 of 1521  
TI: Decomposition of dissolved DMSP and DMS in estuarine waters: Dependence on temperature and substrate concentration.
AU: Kiene,-R.P.; Service,-S.K.
AF: Univ. Georgia Mar. Inst., Sapelo Island, GA 31327, USA
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 76, no. 1, pp. 1-11
NT: Bibliogr.: 42 ref.
LA: English
ER: M (Marine)
AB: Dimethylsulfide (DMS) is an important trace gas which is emitted from seawater to the atmosphere. DMS is believed to be derived primarily from the plant osmolyte 3-(dimethylsulfonium)-propionate (DMSP). This study examined the decomposition of dissolved DMSP (DMSP sub(diss)), the production of DMS from DMSP sub(diss), and the consumption of DMS in estuarine waters near Sapelo Island, Georgia, USA. Rate of DMSP sub(diss) disappearance from seawater was directly proportional to the concentration of DMSP sub(diss), over the range of concentrations tested (20 to 100 nM), and was a function of temperature; rates were very low at 4 degree C and increased progressively at 16, 23 and 30 degree C. At 49 degree C the rate of DMSP sub(diss) metabolism was substantially lower. The production of DMS from DMSP sub(diss) displayed similar concentration and temperature dependence. A mass balance of total DMSP during dark incubations indicated that < 30% of the DMSP consumed during the experiments was converted to DMS, even when chloroform (500  mu M) was included to prevent DMS consumption.
AN: 2692888

                                                                   1035 of 1521  
TI: Removal of total phosphorus and phosphate by peat soils of the Florida Everglades.
AU: Jones,-R.D.; Amador,-J.A.
AF: Dep. Biol. Sci., Florida International Univ., Miami, FL 33199, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1992. vol. 49, no. 3, pp. 577-583
LA: English
ER: F (Freshwater)
AB: Traditional estimates of soil and sediment phosphorus retention are based on orthophosphate (PO sub(4)) removal from water by soil or sediment columns under saturated water flow. These techniques may not reflect the P uptake of in situ soils accurately because the PO sub(4) concentration of through-flowing water is often below detection limits in nonpolluted wetlands during the growing season. We used peat soils from the Florida Everglades in saturated flow and equilibrium sorption experiments to show that the uptake of PO sub(4) reaches saturation quickly, potentially underestimating soil P binding capacity when compared with total phosphorus (TP) retention. Removal of TP by these soils appears to involve abiotic mechanisms that include both hydrophobic and ionic interactions.
AN: 2692405

                                                                   1036 of 1521  
TI: Cycling of some trace elements in Lake Constance.
OT: Stoffkreislaeufe ausgewaehlter Spurenelemente im Bodensee
AU: Stabel,-H.-H.; Kleiner,-J.; Merkel,-P.; Sinemus,-H.W.
AF: Betriebs-Forschungslab., ZV Bodenseewasserversorgung, D-W 7770 Ueberlingen-Suessenmuehle, FRG
SO: VOM-WASSER. 1991. vol. 76, pp. 73-91
NT: Bibliogr.: 34 ref.
