PERSONAL INFORMATION

Name: VEDULA V.S.S. SARMA

Date & place of birth: 15 th June 1969 at Amalapuram, Andhra Pradesh, India

Nationality: Indian

Matrial status: Unmarried

Sex: Male

Address: Chemical Oceanography Division,

National Institute of Oceanography,

Dona Paula 403 004,

GOA, INDIA

Ph: (Off) +91 (0)832 226253/221322 Exn:4403

(Res) +91 (0)832 225127

Fax: +91 (0)832 223340/221360/229102

e-mail: vsarma@csnio.ren.nic.in

FORMATION

1993/97 Research Student at National Institute of Oceanography, Dona Paula, Goa,India and submitted thesis for doctorate degree at Goa University, Goa, India.

1991/93 M.Sc., in Chemical Oceanography/Marine Chemistry, Andhra University, Visakhapatnam, India, FIRST class

1990/91 Diploma in Computer Applications, Industrial Training Institute, Kakinada, India, FIRST class

1987/90 B.Sc., Chemistry, Botany and Zoology, Andhra University, Visakhapatnam, India, FIRST class

PROFESSIONEL EXPERIENCE

1998 Ph.D. Thesis submitted on  Variability in forms and fluxes of carbon dioxide in the Arabian Sea  to Goa University, India

97/98 -Pre-doctorate - worked with Prof. Edouard BARD (ebard@cerege.fr), CEREGE, Europole Mediterraneen de l’Arbois, Aix-en Provence, France for ONE year on Reconstruction of paleoproductivity using isotopic ratios of thorium in the Arabian Sea

93/97 - Research Student - worked under guidance of Dr. M. Dileep Kumar (dileep@csnio.ren.nic.in), Scientist, National Institute of Oceanography, Goa for 3 years and 6 months on Variability in forms and fluxes of carbon dioxide in the Arabian Sea under Joint Global Ocean Flux Studies (JGOFS) - India Programme.

95/96 -Research Student - worked with Dr. S.W.A. Naqvi (naqvi@csnio.ren.nic.in), Scientist, National Institute of Oceanography, Goa, India, for ONE year on Tropical Dynamics: Biogeochemical cycling of the carbon and nitrogen in

the Arabian Sea under Indo-US Trophic Dynamics programme, in colloboration with Dr. T. Yoshinari, Wordsworth State University for health, Albany, USA.

96/97 - Research Student -worked at National Institute of Oceanography, Goa, India for ONE year on Distribution of surface water partial pressure of carbon dioxide in the Arabian Sea: continuous measurements in colloboration with Dr.Catherine GOYET (cgoyet@whoi.edu), Woods Hole Oceanographic Institution, USA.

97/98 -Research Student - working at National Institute of Oceanography, Goa, India on Reconstruction of changes in the oxygen minimum of the Arabian Sea during the late quaternary: Link with the monsoon under the Indo-French colloborative project.

SUMMARY OF THE PROJECTS

1. Joint Global Ocean Flux Study (JGOFS, a core project of International Geosphere Biosphere Programme): Under this programme detailed studies have been carried out on Variability in forms and fluxes of carbon dioxide from the Arabian Sea under the project Biogeochemical cycling of carbon and nitrogen in the Arabian Sea under the Joint Global Ocean Flux Studies Programme. Five cruises have been undertaken, which are interdisiplinary in nature, on board ORV Sagar Kanya in different seasons.

In this project, main emphasis was to undersand carbon cycling in the Arabian Sea through the links among physical, chemical, biological and geological influences on carbon components. Extensive data were collected on dissolved carbon components such as total carbon dioxide, total alkalinity, pH, pCO2 to study seasonal and spatial variability in forms of dissolved carbon components, Data analysis had been carried out to understand controls of physical and biological processes on partial pressure of carbon dioxide in the surface layers and to identify sink and source regions of carbon dioxide to the atmosphere in the Arabian Sea.

To address the question which carbon pool is supporting the subsurface bacterial respiration, dissolved organic carbon and transparent exopolymer particles (TEPs) and their inter-relationships have been studied in addition to their influence on denitrification process. Role of bacteria on formation of DOC from TEP were studied. These results indicate that TEP significantly supports the bacterial respiration in the northern Arabian Sea.

14 day-time series observations were also made at 21° N, 64° E during NE monsoon to examine diurnal and dialy variability in carbon components and influence on biological and physical processes. These results indicated that carbon components are highly influenced by biological processes during this season and the effect is dicernible even upto 500 m.

Carbon budgets in the study region of the Arabian Sea were constructed. This shows that 70-75% of the carbon is remineralized within the mixed layer. Other important point here is that influx of carbon dioxide from atmosphere is 5 times higher than outfluxes.

The effect of soil-water interaction on pH in Mandovi-Zuari estuaries, Goa, India and its influence on the fluxes of carbon dioxide at air-water interface was studied. This study shows that if riverine sediments are acidic in nature it results in a decrease in river water pH. This would ultimately effect the carbonate equilibrium in the waters, i.e., equilibrium shifts towards the formation of pCO2. This increases sea-to-air fluxes of carbon dioxide.

During these studies on carbon dioxide cycling Carbon Coulometer, Total Organic Carbon (TOC 5000) analyser, Underway pCO2 analyser, Auto analyser, UV/Vis spectrophotometers were used to collect high quality data. Semi-automated sample drawing system for inorganic carbon analysis was developed at National Institute of Oceanography, Goa, which enable to subsample without contamination of atmopshere.

2. Trophic Dynamics: Biogeochemical cycling of the carbon and nitrogen in the Arabian Sea

Under this programmes, five cruises have been under taken on board ORV Sagar Kanya and FORV Sagar Sampada. This project mainly emphasizes on biogeochemical cycling of carbon and nitrogen in coastal waters of the SW coast of India. SW coast of India is one of the intensive upwelling zones in the Arabian Sea. But here fresh water inhibits the upward pumping and acts as a lid. To examine the influence of these processes on biogeochmical cycling of carbon and nitrogen in the Arabian Sea and their inter-annual variations, data were collected along 15° N during pre, SW and post monsoon periods and also along the coast from 8° N -15° N during SW monsoon season from 1995 to 1998. Very high surface pCO2 concentrations (682 µatm) were observed at 10.5° N, 72° E where intense upwelling takes place and these high concentrations have never been reported sofar from this region. Along northwest coast of India, these concentrations were low (<200 µatm) due to influence of fresh water inputs from the continent. There is a large gradient of 250-350 µatm of pCO2 between surface and 20 m due to surpression of upwelling by fresh waters due to buoyancy.

The complete consumption of nitrate in the water column was observed which indicates intense denitrification. The intensity of denitrification seems to be highly variable. The dynamics of dissolved organic carbon in these waters are also studied.

3. Distribution of surface water partial pressure of carbon dioxide in the Arabian Sea: continuous underway measurements

The northern Indian Ocean appears to serve as a significant source of carbon dioxide to the atmosphere. However, estimates of CO2 flux from the northern Indian Ocean suffer from large uncertainties due to inadequate coverage of the region both in space and time.

The continuous surface water pCO2 data were collected under the colloboration with Dr. Catherine Goyet, WHOI, USA, during SW monsoon in the eastern and central Arabian Sea and western and central Bay of Bengal. During this season, the surface pCO2 concentrations were higher than the atmospheric values in the northern Indian Ocean and varied between 400-440 and 360-411 in the Arabian Sea and Bay of Bengal respectively. Winds were stronger in the Arabian Sea to a maximum of 43 km/h than in the Bay of Bengal (13 km/h). This together with pCO2 >360 µatm resulted in CO2 evasion from the Arabian Sea as well as from the Bay of Bengal. A patch of high pCO2 waters were observed at 17° N to 19° N of 64° E due to Findlater jet or gyral circulation. The concentrations varied widely from 200 to 685 µatm in the coastal zone. High pCO2 along the SW coast of India is due to wind driven coastal upwelling and lower concentrations in the NW coast of India due to influence of fresh waters from the continents. Except these small zones rest of the eastern and central Arabian Sea acts as a pernnial source to atmospheric carbon dioxide. The average fluxes obtained in the study region yields 20 Tg for SW monsoon season. An annual flux from the study area (using other data) is 45 Tg/y (6.4 mM.m2.d-1). A tentative extrapolation to entire Arabian Sea amounts to 180 Tg/y whereas Bay of Bengal pumps 6 Tg of carbon per year through air-sea interface to the atmosphere.

 

4. Reconstruction of paleoproductivity using thorium isotopes in the Arabian Sea

The paleo-oceanography of the Arabian Sea is not well known. The Arabian Sea houses one of the most intense water-column denitrification sites in the world oceans. The extent of sub-oxic conditions is known to fluctuate in the geological past with changes in climate. This project is to understand the links and assess phase lags between physical forcing (mixing and circulation, mainly upwelling associated with Asian summer monsoon) and biogeochemical responses. The physical forcing is closely related to the climatic forcing and to its variations.

Based on the results of Cd content of certain species of benthic foraminifera, it has been suggested that the intermediate waters of the northern Indian Ocean were greatly depleted in nutrients during the last glacial maximum which has important implications for glacial-interglacial atmospheric carbon dioxide changes. As oxygen minimum zone plays very important role in the production of greenhouse gases like carbon dioxide, nitrous oxide etc. it is highly necessary to reconstruct the changes in this zone during past and its relation to atmospheric carbon dioxide.

Under this project, work has been carried out on organic carbon accumulation and to understand reasons for preservation, whether due to variations in oxygen minimum zone or productivity using redox sensitive elements such as Uranium, Molybdnum etc. The work has been carried out on 3 cores of 5 m long each. Among three, two of them were risen from oxygen minimum zone and one from well below the OMZ. Sediment organic carbon showed wide variations i.e., >3% in the OMZ cores than other one <1%. The cores from the OMZ showed two episodes of organic carbon rich layers which might be related to either increased surface productivity or intense oxygen minimum zone. These episodes coincided with the high molybdenum concentrations (Dr. D. Cardinal, personal communication). Enhanced concentrations of uranium in deep-sea sediments have been found in the reduced sediments. In most of the cases, it can be shown that sea water, with its characteristic 234U/238U activity ratio of 1.149, is the source of the authigenic uranium. The most common interpretations of core sections with high U contents are therefore that they record episodes of increased surface productivity giving rise to underlying reduced sediments. It is essential to separate authigenic fraction of uranium from the bulk sample. Hence, we developed a methodology to separate authigenic fraction of uranium from the bulk sample through their isotopic ratios.

Apart from this, bulk isotopic ratios of thorium (230/232 Th) were studied on MD900963 core at CEREGE, France which has beeen risen from eastern shoalder of the Maldives in the Arabian Sea. These ratios are used as proxy to study paleoproductivity. Using this proxy, paleoproductivity has been reconstructed upto 200 kyr BP.

INSTRUMENTATION SKILLS

 

MODELLING EXPERIENCE

FIELDS OF INTEREST

 

PUBLICATIONS and COMMUNICATIONS

1. Sarma, V.V.S.S., Kumar, M.D., George, M.D., and Rajendran, A., 1996. Seasonal variations in inorganic carbon components in the centnral and eastern Arabian Sea, Curr. Sci., 71, 852-856.

2. de Sousa, S.N., Kumar, M.D., Sardessai, S., Sarma, V.V.S.S., and Shirodkar, P.V., 1996. Seasonal variability in oxygen and nutrients in the central and eastern Arabian Sea, Curr. Sci., 71, 847-851.

3. Sarma, V.V.S.S., Kumar, M.D., and George, M.D., 1998. The central and eastern Arabian Sea as a pernnial source to atmospheric carbon dioxide. Tellus, 50B, 179-184.

4. Kumar, M.D., Sarma, V.V.S.S., Ramaiah, N., and Gauns, M. 1998. Dynamics of Transparent Exopolymet Particles in the Northern Indian Ocean. Geophys. Res. Lettrs.,25, 81-84.

5. Patra, P.K., Lal, S.S., Venkataramani, S., Gauns, M., and Sarma, V.V.S.S., 1998. Seasonal variability in distribution and fluxes of methane in the Arabian Sea. J. Geophys. Res., 103, 1167-1176.

6. Sardessai, S., Sarma, V.V.S.S and Kumar, M.D., 1997. Particulate Organic Carbon and its Humic fractions in the Arabian Sea, Ind. J. Mar.Sci., (in press).

7. Naik, H., Murty, V.M., Sarma, V.V.S.S., and Sangodkar, U.M.X., 1997. The distribution of Boron and fluride in the Arabian Sea during SW monsoon, Ind.J. Mar.Sci., (in press)

8. Sarma, Y.V.B., Rao, E.P.R., Saji, P.K. and Sarma, V.V.S.S., 1997. Hydrographic characteristics of the Bay of Bengal during withdrawal phase of southwest monsoon. Oceanologica Acta., (in press)

9. Patra, P.K., Lal. S.S., Venkataramani, S., de Sousa, S.N., Sarma, V.V.S.S., and Sardessai, S., 1997. Seasonal and spatial variability in nitrous oxide distribution in the Arabian Sea. Deep-Sea Res.,(Revised version submitted)

10. Sarma, V.V.S.S., Kumar, M.D., de Sousa, S.N., and George, M.D., 1997. Carbon dioxide in the Northern Indian Ocean during southwest monsoon. Mar.Chem., (submitted)

11. Sarma, V.V.S.S., Kumar, M.D., and Gauns, M., 1997. Seasonal change in control of surface pCO2 in the Arabian Sea. J. Geophys. Res., (submitted)

12. Shenoy, D.M., Murty, V.M., Sarma, V.V.S.S., and Sangodkar, U.M.X., 1997. The distribution of calcium and magnesium in the Arabian Sea during SW monsoon, Ind.J. Mar.Sci., (submitted)

13. Sarma, V.V.S.S. Kumar, M.D. and George, M.D. 1997. Stability, Chemical Absorption and Bubble model for transfer velocity of carbon dioxide. J. Geophys. Res., (submitted)

14.Prasanna Kumar, S., Madhupratap, M., Kumar, M.D., Muraleedharan, P.M., Sawant, S., Gauns, M., de Sousa, S.N. and Sarma, V.V.S.S. 1998. High biological productivity in the interior Arabian Sea during summer monsoon driven by Ekman pumping and lateral advection. J. Geophys. Res., (Revised version was submitted)

15. Narvekar, P.V., Sarma, V.V.S.S., and Kumar, M.D., 1997. MARCHEM: GW-BASIC program for computation in chemical oceanography, submitted for copyrights to Council of Scientific and Industrial Research (CSIR), New Delhi, India.

 

SYMPOSIA/CONFERENCES:

1. Narvekar, P.V., Naqvi, S.W.A., Jayakumar, A., Sarma, V.V.S.S., and Nasnolkar, C.M., 1996. Chemical signatures of upwelling off southwest coast of India, American Geophysical Union, San Diego, USA.

2. Sarma, V.V.S.S., Kumar, M.D., George, M.D., and Rajendran, A., 1996. Seasonal variations in inorganic carbon components in the central and eastern Arabian Sea, Climate Change by International Geosphere Biosphere Programme, Bhubhaneswar, Orissa, India.

3. de Sousa, S.N., Kumar, M.D., Sardessai, S., Sarma, V.V.S.S., and Shirodkar, P.V., 1996. Seasonal Variability in oxygen and nutrients in the central and eastern Arabian Sea, Climate Change by International Geosphere Biosphere Programme, Bhubhaneswar, Orissa, India.

4. Sarma, V.V.S.S., Kumar, M.D., George, M.D., and Rajendran, A., 1996. Seasonal variations in inorganic carbon components in the central and eastern Arabian Sea, National workshop on scientific achievements of ORV Sagar Kanya (16-17, June 1997), NIO, Goa, India 16 pp.

5. Sarma, V.V.S.S., Manelkar, M and Kumar, M.D., 1997. Behaviour of pH and Carbon dioxide in a monsoon influenced tropical estuary, National symposium on Oceanography and Coastal Zone Management (23-24, April, 1997), NIO, RC, Visakhapatnam.

6. Sarma, V.V.S.S., and Kumar, M.D., 1998. Control of pH by rock-water interactions and air-sea exchange of carbon dioxide in a tropical estuary, XII General meeting of European Geophysical Society, Nice, France OA 161.

7. Sarma, V.V.S.S. and Kumar, M.D. 1998. Controls of pCO2 and its air-water exchange in the Arabian Sea. Will be presenting at JGOFS International Scientific Symposium onBiogeochemistry of the Arabian Sea: Synthesis and Modelling going to be held at Bangalore, India on 18-20th January 1999 (accepted for presentation).

8. Ramaiah, N. Sarma, V.V.S.S. Gauns, M, Kumar, M.D. and Madhupratap, M. 1998. Bacterial relationship with Organic carbon in the Arabian Sea. Will be presenting at JGOFS International Scientific Symposium onBiogeochemistry of the Arabian Sea: Synthesis and Modelling going to be held at Bangalore, India on 18-20 th January 1999 (accepted for presentation).

 

OTHER ACTIVITIES:

Computer programming: MARCHEM package was developed to compute fundamental parameters in physical, meteorological and chemical oceanography, such as salinity from autosal, potential temperature, density, sigma-t, vapor pressure, saturated vapor pressure, apparent oxygen utilisation, deficit nitrogen, spectrophotometric pH measurements, alkalinity (BCG method), inorganic carbon components such as bicarbonate, carbonate, partial pressure of carbon dioxide, total carbon dioxide using total alkalinity and pH, carbonate solubility, air-sea fluxes of carbon dioxide etc. .

Knowledge in FORTRAN, dBASE IV, Q and TURBO BASIC and packages like LOTUS 123, SURFER, GRAPHER, and other graphical packages.

Onboard analysis during Cruises: Participated 16 oceanographic cruises (320 days) onboards ORV Sagar Kanya and FORV Sagar Sampada in the Indian Ocean. Collection of air, water and sediment samples and onboard analysis of gases such as dissolved oxygen, total carbon dioxide, nitrous oxide, methane and other oceanographic parameters such as total alkalinity, pH, nutrients. Collection of sediment pore waters under inert atmosphere for redox sensitive elements and sampling for other paleoceanographic studies.