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Water column and sediment geochemical data taken by bottle and bottom samples from research vessel Atlantis (cruise AT41) in the southeastern U.S. Atlantic margin from 2018-08-21 to 2018-08-31 (NCEI Accession 0242498)

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This dataset contains water column and sediment geochemical data taken by bottle and bottom samples from research vessel Atlantis (cruise AT41) in the southeastern U.S. Atlantic margin in August 2018. Data include nutrients, nitrate, phosphorus, and other chemical characteristics. There are CTD data for this expedition archived at NCEI under accession number 0177873.

This cruise is part of the DEEP Sea Exploration to Advance Research on Coral/Canyon/Cold seep Habitats (DEEP SEARCH) project, the goal of which is to explore a variety of deep sea ecosystems off the southeastern U.S. Atlantic margin. Data are in CSV format.

Dataset Citation

Cite as: Hunter, Kimberley; Choi, Hannah; Joye, Samantha (2021). Water column and sediment geochemical data taken by bottle and bottom samples from research vessel Atlantis (cruise AT41) in the southeastern U.S. Atlantic margin from 2018-08-21 to 2018-08-31 (NCEI Accession 0242498). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0242498. Accessed [date].

Dataset Identifiers

ISO 19115-2 Metadata

gov.noaa.nodc:0242498

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Ordering Instructions	Contact NCEI for other distribution options and instructions.
Distributor	NOAA National Centers for Environmental Information +1-301-713-3277 ncei.info@noaa.gov
Dataset Point of Contact	NOAA National Centers for Environmental Information ncei.info@noaa.gov

Time Period	2018-08-21 to 2018-08-31
Spatial Bounding Box Coordinates	West: -78.5 East: -74.75 South: 31 North: 37.25
Spatial Coverage Map

General Documentation	NCEI Dataset Landing Page Navigate directly to the URL for a descriptive web page with download links. Descriptive Information Navigate directly to the URL for a descriptive web page with download links.
Associated Resources	Lunden, Jay; Keller, Abigail; Cordes, Erik (2018). Water temperature, salinity, and other profiles collected by CTD from R/V Atlantis in the North Atlantic from 2018-08-21 to 2018-09-01 (NCEI Accession 0177873). NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0177873. https://www.ncei.noaa.gov/archive/accession/0177873 Related data

Publication Dates	publication: 2021-11-02 creation: 2021-10-29
Data Presentation Form	Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status	Complete - production of the data has been completed Historical archive - data has been stored in an offline storage facility
Data Update Frequency	As needed
Purpose	This dataset is available to the public for a wide variety of uses including scientific research and analysis.
Use Limitations	accessLevel: Public Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.

Dataset Citation	Cite as: Hunter, Kimberley; Choi, Hannah; Joye, Samantha (2021). Water column and sediment geochemical data taken by bottle and bottom samples from research vessel Atlantis (cruise AT41) in the southeastern U.S. Atlantic margin from 2018-08-21 to 2018-08-31 (NCEI Accession 0242498). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0242498. Accessed [date].
Cited Authors	Hunter, Kimberley Choi, Hannah University of Georgia (UGA) Joye, Samantha
Principal Investigators	Samantha Joye University of Georgia, School of Marine Programs
Collaborators	Kimberley Hunter University of Georgia, School of Marine Programs
Contributors	University of Georgia, School of Marine Programs
Resource Providers	Hannah Choi University of Georgia (UGA) University of Georgia, School of Marine Programs
Publishers	NOAA National Centers for Environmental Information
Acknowledgments	Funding Agency: NOAA Ocean Exploration Funding Agency: US DOI; Bureau of Ocean Energy Management

Theme keywords	NODC DATA TYPES THESAURUS AMMONIUM (NH4) CARBON - TOTAL PARTICULATE - SEDIMENT CHEMISTRY - SEDIMENT CORE - POROSITY DEPTH - BOTTOM DISSOLVED INORGANIC CARBON (DIC) DISSOLVED ORGANIC CARBON Dissolved Organic Nitrogen Hydrogen Sulfide (H2S) LATITUDE LONGITUDE Methane (CH4) NITRATE nitrate + nitrite content (concentration) NITRITE NITROGEN pH phosphate SALINITY total alkalinity Total Dissolved Nitrogen (TDN) NODC OBSERVATION TYPES THESAURUS chemical in situ laboratory analyses physical pore water chemistry sediment analysis WMO_CategoryCode oceanography Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > WATER DEPTH EARTH SCIENCE > OCEANS > MARINE SEDIMENTS > SEDIMENT CHEMISTRY EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > ALKALINITY EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > AMMONIA EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > CARBON EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > INORGANIC CARBON EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > NITRATE EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > NITRITE EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > NITROGEN EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > ORGANIC CARBON EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > PH EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > PHOSPHATE EARTH SCIENCE > OCEANS > SALINITY/DENSITY > SALINITY Provider Variable Names Aerobic Methane Oxidation (water column) Anarobic Methane Oxidation Rate (sediments) DISSOLVED INORGANIC CARBON (DIC) (pore water) Dissolved Inorganic Nitrogen (DIN) Dissolved Inorganic Nitrogen to Dissolved Inorganic Phosphorus ratio (DIN:DIP) Dissolved Organic Nitrogen to Dissolved Organic Phosphorus ratio (DON:DOP) Dissolved Organic Phosphorus (DOP) Experimental anaerobic methane oxidation rate (sediments) Hydrogen Sulfide (H2S) (pore water) Iron II oxide (pore water) Maximum section depth (sediments) Mean delta 13C of methane Minimum section depth (sediments) PARTICULATE ORGANIC CARBON (sediments) Redox potential (Eh) (sediments) Section midpoint depth (sediments) Sediment organic matter (loss on ignition method) Standard deviation delta 13C of methane Sulfate (SO4 2-) (pore water) Sulfate Reduction Rate (sediments) Total Dissolved Phosphorus Total Particulate Nitrogen (sediments) Total alkalinity (pore water) Total particulate phosphate (sediments)
Data Center keywords	NODC COLLECTING INSTITUTION NAMES THESAURUS University of Georgia, School of Marine Programs NODC SUBMITTING INSTITUTION NAMES THESAURUS University of Georgia, School of Marine Programs
Platform keywords	NODC PLATFORM NAMES THESAURUS R/V Atlantis Global Change Master Directory (GCMD) Platform Keywords Ships ICES/SeaDataNet Ship Codes ATLANTIS (call sign: KAQP, ICES code: 33AT, 1997-) Provider Platforms Hunan Occupied Vehicle (HOV) Alvin
Instrument keywords	NODC INSTRUMENT TYPES THESAURUS bottle CTD multibeam sonar Niskin bottle scintillation counter spectrophotometer Total Organic Carbon (TOC) analyzer Global Change Master Directory (GCMD) Instrument Keywords CTD > Conductivity, Temperature, Depth MBES > Multibeam Mapping System NISKIN BOTTLES OPTSPEC > Optical Spectrometer SCINTILLATION COUNTERS > SCINTILLATION COUNTERS TOC > Total Organic Carbon Analyzer Provider Instruments Antek Instruments 7050 nitric oxide (NO) chemiluminescent detector Beckmann Coulter LS6500 Liquid Scintillation Counter Dionex Integrion HPIC System Eh probe Hand Held Refractometer Picarro G2201-i Cavity Ring-Down Spectroscopy (CRDS) Ross pH electrode SRI 8610 Gas Chromatograph GC-FID Shimadzu TOC-V CPH Total Nitrogen Measurement (TNM) Total Nitrogen Analyzer Shimadzu UV1601 Spectrophotometer ThermoFinnigan Flash EA 1112 series NC Soil Analyzer
Place keywords	NODC SEA AREA NAMES THESAURUS North Atlantic Ocean Global Change Master Directory (GCMD) Location Keywords OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN Provider Place Names U.S. Atlantic margin
Project keywords	Provider Projects DEEP Sea Exploration to Advance Research on Coral/Canyon/Cold seep Habitats (DEEP SEARCH)
Keywords	NCEI ACCESSION NUMBER 0242498
Keywords	Send2NCEI Submission Package ID RLFTAA

Use Constraints	Cite as: Hunter, Kimberley; Choi, Hannah; Joye, Samantha (2021). Water column and sediment geochemical data taken by bottle and bottom samples from research vessel Atlantis (cruise AT41) in the southeastern U.S. Atlantic margin from 2018-08-21 to 2018-08-31 (NCEI Accession 0242498). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0242498. Accessed [date].
Access Constraints	Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Fees	In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.

Lineage information for: dataset
Processing Steps	2021-11-02T15:35:13Z - NCEI Accession 0242498 v1.1 was published.
Output Datasets	NCEI Accession 0242498 v1.1 NCEI Accession 0242498 v1.1 (download) published 2021-11-02T15:35:13Z

Lineage information for: dataset
Processing Steps	Parameter or Variable: pH (measured); Units: pH scale; Observation Category: laboratory analysis; Sampling Instrument: Ross pH electrode; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Measurements on small pore water volumes carried out using a flow-through cell. Ross electrode (Thermo Fisher, Prod. No. 8103BNUWP) was calibrated with buffers of pH 4, 7, and 10. Water column pH measured while continuously stirring. Parameter or Variable: SALINITY (measured); Units: psu; Observation Category: laboratory analysis; Sampling Instrument: handheld refractometer Parameter or Variable: NITRITE (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Pore water and water column samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Nitrite was measured colorimetrically using method of Bendschneider and Robinson, 1952; reproduced by Parsons et al. 1984. Absorbance was measured on a Shimadzu UV1601 spectrophotometer. Parameter or Variable: nitrate + nitrite content (concentration) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Antek Instruments 7050 NO detector; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Pore water and water column samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. NOx (nitrite + nitrate) was chemically reduced and measured with a nitric oxide detector according to the method of Garside 1981 using an Antek Instruments 7050 Nitric Oxide Detector with 745 Nitrate/Nitrite Reduction Assembly. Parameter or Variable: NITRATE (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by subtracted measured nitrite concentration from measured NOx (nitrite + nitrate) concentration Parameter or Variable: AMMONIUM (NH4) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Ammonium measured colorimetrically using the phenolhypochlorite method developed by Solorzano, 1969, on a Hach Company DR 2800 spectrophotometer. Parameter or Variable: Dissolved Inorganic Nitrogen (DIN) (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by adding measured NOx (nitrite + nitrate) concentration and measured NH4 concentration Parameter or Variable: Total Dissolved Nitrogen (TDN) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu TOC-Vcph TNM Total Nitrogen Analyzer; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Samples analyzed using a Shimadzu Instruments TOC-Vcph Total Organic Carbon Analyzer with ASI-V Autosampler and TNM Total Nitrogen Analyzer, according to method of Watanabe et al. 2007. Parameter or Variable: Dissolved Organic Nitrogen (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: DON concentrations calculated by subtracted the calculated dissolved inorganic nitrogen concentration from the total dissolved nitrogen concentration Parameter or Variable: phosphate (measured); Units: micrmole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Phosphate was measured on a Shimadzu UV1601 spectrophotometer according to the colorimetric method of Strickland and Parsons, 1972. Parameter or Variable: Total Dissolved Phosphorus (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a 0.2 micron cellulose filter and frozen until time of analysis. TDP concentrations measured on a Shimadzu UV1601 spectrophotometer according to the colorimetric method of of Solorzano and Sharp, 1980. Parameter or Variable: Dissolved Organic Phosphorus (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by subtracting the measured phosphate concentrations from the measured total dissolved phosphorus concentrations Parameter or Variable: DIN:DIP (calculated); Units: molar ratio (unitless); Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by dividing the calculated DIN concentration by the measured phosphate concentration. Parameter or Variable: DON:DOP (calculated); Units: molar ratio (unitless); Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by dividing the calculated dissolved organic nitrogen concentration by the calculated dissolved organic phosphorus ratio. Parameter or Variable: DISSOLVED ORGANIC CARBON (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu TOC-Vcph TOC Analyzer; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. DOC was measured on a Shimadzu Instruments TOC-Vcph Total Organic Carbon Analyzer with ASI-V Autosampler and TNM Total Nitrogen Analyzer according to the method of Sugimura and Suzuki, 1988. Parameter or Variable: LATITUDE (measured); Units: decimal degrees; Observation Category: other; Sampling Instrument: shipboard GPS Parameter or Variable: LONGITUDE (measured); Units: decimal degrees; Observation Category: other; Sampling Instrument: shipboard GPS Parameter or Variable: Sample depth (measured); Units: meters; Observation Category: in situ; Sampling Instrument: CTD Parameter or Variable: DEPTH - BOTTOM (measured); Units: meters; Observation Category: in situ; Sampling Instrument: multibeam sonar Parameter or Variable: Date (measured); Units: mo/day/year; Observation Category: other; Sampling Instrument: none Parameter or Variable: Local time (measured); Units: hh:mm; Observation Category: other; Sampling Instrument: none; Sampling and Analyzing Method: Time of sample collection in Eastern Daylight Time (UTC-4:00) Parameter or Variable: redox potential (Eh) (sediments) (measured); Units: mV; Observation Category: laboratory analysis; Sampling Instrument: Eh probe; Sampling and Analyzing Method: Whole sediment Eh was measured during core sectioning. Parameter or Variable: minimum section depth (sediments) (measured); Units: centimeters below surface (cmbsf); Observation Category: laboratory analysis; Sampling Instrument: ruler; Sampling and Analyzing Method: The distance between sediment-water interface and the top of the sediment core section. Parameter or Variable: maximum section depth (sediments) (measured); Units: centimeters below surface (cmbsf); Observation Category: laboratory analysis; Sampling Instrument: ruler; Sampling and Analyzing Method: The distance between the sediment-water interface and the bottom of the sediment core section. Parameter or Variable: section midpoint depth (sediments) (calculated); Units: centimeters below surface (cmbsf); Observation Category: laboratory analysis; Sampling Instrument: ruler; Sampling and Analyzing Method: The distance between the sediment-water interface and the midpoint of the sediment core section, or, the average of the section minimum depth and section maximum depth Parameter or Variable: total alkalinity (pore water) (measured); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: Pore water was extracted using a manual press. Water was filtered through a 0.2 micron pre-rinsed cellulose filter. Alkalinity was determined using the spectrophotometric method described by Sarazin et al., 1999. Parameter or Variable: DISSOLVED INORGANIC CARBON (DIC) (pore water) (calculated); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: calculated; Sampling and Analyzing Method: DIC concentrations were calculated from the measured alkalinity values as follows: DIC = Alkalinity * (alpha1 + 2alpha2) where alpha1 = [HCO3] [DIC] alpha2 = [CO3] * [DIC] alpha1 and alpha2 were determined using K1 and K2 of carbonic acid dissolution pK1 and pK2 were determined from temperature and salinity according to Luecker et al. 2001: pK1 = 3633.86/T – 61.2172 + 9.67770 * ln(T) – 0.011555 * S + 0.0001152 * S2 pK2 = 471.178/T + 25.9290 – 3.1697 * ln(T) – 0.01781 * S + 0.0001122 * S2 Parameter or Variable: Methane (CH4) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: SRI 8610 GC-FID; Sampling and Analyzing Method: Sediment samples (3 cubic centimeters) were collected into a glass serum vial, preserved with N2-purged 2M NaOH (3 milliliters), crimp-sealed with a butyl rubber stopper and stored at room temperature until analysis. Concentrations were determined by headspace analysis using an SRI 8610C gas chromatograph equipped with a flame ionization detector and SRI Hayesep D 6’x1/8” column (Prod. No. 8600-PKDB). Water column gas samples were collected by overflowing a 1 L PETG bottle and closing headspace-free with a silicone septum cap. A modified 1 L glass media bottle was evacuated to a pressure of 0.2 Torr or below. A 0.7 L aliquot of sample from the PETG was pulled into the evacuated bottle. The 0.7 L sample was shaken and sonicated 3x before the pressure was equilibrated by the addition of brine purged with UHP nitrogen. Extracted gases were collected from the top of the modified media bottle using a syringe and stored in 20 mL serum vials filled with brine. Methane concentrations were determined by injecting gas samples from the brine vials onto an SRI 8610 GC-FID and SRI Hayesep D 6’x1/8” column (Prod. No. 8600-PKDB). See Schmitt, 1991 and Lammers, 1994. Parameter or Variable: Mean delta 13C of methane (measured); Units: permil; Observation Category: laboratory analysis; Sampling Instrument: Picarro G2201-i CRDS; Sampling and Analyzing Method: Methane isotopic ratios were measured out of the same vials as methane concentrations. 2 mL (sediments) or 5 ml (water column) of headspace from the methane vials (3 cc sediment preserved with 3 mL UHP N2 purged 2 M NaOH for sediments, 20 mL vials of brine for water column) was injected into the Small Sample Introduction Module of the Picarro CRDS. Parameter or Variable: Standard deviation delta 13C of methane (measured); Units: permil; Observation Category: laboratory analysis; Sampling Instrument: Picarro G2201-i CRDS; Sampling and Analyzing Method: Standard deviation of several measurements taken over the course of 4 minutes by the Picarro G2201-i CRDS. Parameter or Variable: Hydrogen Sulfide (H2S) (pore water) (measured); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: Pore water was extracted using a manual press. 2 mL unfiltered porewater was collected into a 15 mL centrifuge tube containing 100 uL or 500 uL 20% zinc acetate w/v solution and stored at 5°C until analysis. H2S was determined using the colorimetric method described by Cline, 1969. Parameter or Variable: Sulfate (SO4 2-) (pore water) (measured); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: Dionex Integrion HPIC; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water was filtered through a pre-rinsed 0.2 micron cellulose filter. Samples were collected in 7 ml glass vials and preserved with 10 ul HNO3 per ml of sample. Samples were diluted for analysis on a Dionex Integrion HPIC with AS-AP autosampler and AS19 guard and analytical columns; Data Quality Method: Data were corrected for analytical bias and for evaporation using the ratio of measured chloride concentration to expected chloride concentration. Parameter or Variable: Iron II (pore water) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Pore water was filtered through a pre-rinsed 0.2 micron cellulose filter. Samples were collected in 7 ml glass vials and preserved with 10 ul HNO3 per ml of sample. Iron (II) was measured using the spectrophotometric method described by Stookey, 1970. Parameter or Variable: Anarobic Methane Oxidation Rate (sediments) (measured); Units: nanomoles per cubic centimeter per day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann-Coulter LS6500; Sampling and Analyzing Method: Live sediment (3 cc) was transferred into a modified Hungate tube with a Hungate stopper and cap on one end and a modified, movable blue butyl chloride stopper at the other end. Three replicates were sampled per depth, with one kill control sampled per core. Kill controls were killed using 2M NaOH. UHP methane was added to samples expected to have high in situ methane concentrations for a target concentration of 15 mM. Samples were injected with 100 microliters of 14C-methane tracer (1 million dpm). Samples were incubated at in situ pressure and temperature for 1-3 days before termination by addition of 3 mL 2 M NaOH. Samples were later transferred to Erlenmeyer flasks, acidified with 5 mL 30% sulfuric acid, and distilled for 6-8 hours. Evolved carbon dioxide was captured using 3-methoxypropylamine and counted on a Beckman-Coulter 6500 liquid scintillation counter. Rates were calculated using the ratio of counted 14C carbon dioxide to the injected tracer activity and the measured in situ methane concentration. Method described in Bowles et al. 2011 and Joye et al. 2004, adapted from Iversen and Blackburn 1981. Parameter or Variable: Experimental anaerobic methane oxidation rate (sediments) (measured); Units: nanomoles per cubic centimeter per day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann-Coulter LS6500; Sampling and Analyzing Method: Method the same as for Anaerobic Methane Oxidation Rate, except that the added methane (15 mM) plus in situ methane concentration was used in the rate calculation. Parameter or Variable: Sulfate Reduction Rate (sediments) (measured); Units: nanomoles per cubic centimeter per day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann-Coulter LS6500; Sampling and Analyzing Method: Live sediment (3 cc) was transferred into a modified Hungate tube with a Hungate stopper and cap on one end and a modified, movable blue butyl chloride stopper at the other end. Three replicates were sampled per depth, with one kill control sampled per core. Kill controls were killed using 3 mL 20% zinc acetate. Samples were injected with 100 microliters of 35S sodium sulfate tracer (10 million dpm). Samples were incubated at in situ pressure and temperature for 1-3 days before termination by addition of 3 mL 20% zinc acetate. Samples were later spin down in a centrifuge at 5000 rpm for 2 min twice. The supernatant was subsampled and counted to determine the activity of injected sulfate. Sediments were then distilled in hot hydrochloric acid and reduced chromium chloride (TRIS distillations). Evolved hydrogen sulfide was captured in zinc acetate traps and counted on a Beckman-Coulter 6500 liquid scintillation counter. Rates were calculated using the ratio of captured 35S sulfide to injected sulfate activity, the measured pore water sulfate concentration, and the sediment porosity. Method described in Bowles et al. 2011, and Joye et al. 2004, adapted from Fossing and Jorgensen 1989. Parameter or Variable: CORE - POROSITY (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: analytical balance; Sampling and Analyzing Method: Sediment samples were collected into glass scintillation vials, capped and stored at 4°C until analysis. Porosity was determined by drying a sample of known mass at 80°C, weighing, and calculating the moisture content. Parameter or Variable: Sediment organic matter - loss on ignition (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: analytical balance; Sampling and Analyzing Method: Sediment samples were collected into glass scintillation vials, capped and stored at 4°C until analysis. SOM was determined by drying a sample at 80°C, weighing, ashing at 500°C, weighing and calculating weight lost on ignition. Parameter or Variable: Total Particulate Nitrogen (sediments) (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: ThermoFinnigan FlashEA 1112 series NC Soil Analyzer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was dried at 60°C and then homogenized via grinding. TPN was determined by the method described by Gordan, Jr., 1969 as reproduced by Sharp, 1974. Samples were analyzed on a ThermoFinnigan FlashEA 1112 series NC Soil Analyzer. Parameter or Variable: CARBON - TOTAL PARTICULATE - SEDIMENT (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: Thermofinnigan FlashEA 1112 series NC Soil Analyzer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was dried at 60°C and then homogenized via grinding. TPC was determined by the method described by Gordan, Jr., 1969 as reproduced by Sharp, 1974. Samples were analyzed on a ThermoFinnigan FlashEA 1112 series NC Soil Analyzer. Parameter or Variable: PARTICULATE ORGANIC CARBON (sediments) (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: ThermoFinnigan FlashEA 1112 series NC Soil Analyzer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was acidified with 1 N HCl, dried at 60°C, and then homogenized via grinding. POC was determined by the method described by Gordan, Jr., 1969 as reproduced by Sharp, 1974. Samples were analyzed on a ThermoFinnigan FlashEA 1112 series NC Soil Analyzer. Parameter or Variable: Total particulate phosphate (sediments) (measured); Units: micromole/gram sediment; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was dried at 80°C, ground, and distributed into 20 mL scintillation vials. The samples were prepared using the method described by Zhou et. al., 2003. TPP and TPP percent were determined using the colormetric method described by Solorzano and Sharp, 1980. Parameter or Variable: Aerobic Methane Oxidation (water column) (measured); Units: picomoles/liter/day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann Coulter LS6500; Sampling and Analyzing Method: Four technical replicates were collected from each sampled depth by filling 16.6 mL Hungate tubes headspace-free and sealing with exetainer septa. Tubes were stored at 4 °C until injection. One of the four replicates was killed by displacing 1.6 ml sample with 1.6 ml 37% formalin. All samples, including the killed abiotic control, were injected with ~2000000 dpm tritiated methane tracer. Samples were incubated at near-in situ temperature for 1-4 days. Immediately before incubation termination, a 100 ul subsample was removed from each tube and measured on a liquid scintillation counter to determine total dissolved 3H-methane addition. Incubations were terminated by killing with 1.6 ml 37% formalin and purging with air for 1 hour to remove remaining tracer. A 5 ml aliquot of each killed replicate was measured on a liquid scintillation counter to determine the ratio of tracer turnover. The turnover ratio was multiplied by the measured in situ methane concentration to obtain the MOx rate. Killed controls were subtracted and the replicates averaged to obtain the final rate number. See Rogener, 2018 Parameter or Variable: Process Date (measured); Units: mo/day/year; Observation Category: other; Sampling Instrument: none; Sampling and Analyzing Method: Date of sediment core processing

Lineage information for: dataset

Processing Steps

Parameter or Variable: pH (measured); Units: pH scale; Observation Category: laboratory analysis; Sampling Instrument: Ross pH electrode; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Measurements on small pore water volumes carried out using a flow-through cell. Ross electrode (Thermo Fisher, Prod. No. 8103BNUWP) was calibrated with buffers of pH 4, 7, and 10. Water column pH measured while continuously stirring.
Parameter or Variable: SALINITY (measured); Units: psu; Observation Category: laboratory analysis; Sampling Instrument: handheld refractometer
Parameter or Variable: NITRITE (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Pore water and water column samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Nitrite was measured colorimetrically using method of Bendschneider and Robinson, 1952; reproduced by Parsons et al. 1984. Absorbance was measured on a Shimadzu UV1601 spectrophotometer.
Parameter or Variable: nitrate + nitrite content (concentration) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Antek Instruments 7050 NO detector; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Pore water and water column samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. NOx (nitrite + nitrate) was chemically reduced and measured with a nitric oxide detector according to the method of Garside 1981 using an Antek Instruments 7050 Nitric Oxide Detector with 745 Nitrate/Nitrite Reduction Assembly.
Parameter or Variable: NITRATE (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by subtracted measured nitrite concentration from measured NOx (nitrite + nitrate) concentration
Parameter or Variable: AMMONIUM (NH4) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Ammonium measured colorimetrically using the phenolhypochlorite method developed by Solorzano, 1969, on a Hach Company DR 2800 spectrophotometer.
Parameter or Variable: Dissolved Inorganic Nitrogen (DIN) (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by adding measured NOx (nitrite + nitrate) concentration and measured NH4 concentration
Parameter or Variable: Total Dissolved Nitrogen (TDN) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu TOC-Vcph TNM Total Nitrogen Analyzer; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Samples analyzed using a Shimadzu Instruments TOC-Vcph Total Organic Carbon Analyzer with ASI-V Autosampler and TNM Total Nitrogen Analyzer, according to method of Watanabe et al. 2007.
Parameter or Variable: Dissolved Organic Nitrogen (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: DON concentrations calculated by subtracted the calculated dissolved inorganic nitrogen concentration from the total dissolved nitrogen concentration
Parameter or Variable: phosphate (measured); Units: micrmole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. Phosphate was measured on a Shimadzu UV1601 spectrophotometer according to the colorimetric method of Strickland and Parsons, 1972.
Parameter or Variable: Total Dissolved Phosphorus (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD, Shimadzu UV1601; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a 0.2 micron cellulose filter and frozen until time of analysis. TDP concentrations measured on a Shimadzu UV1601 spectrophotometer according to the colorimetric method of of Solorzano and Sharp, 1980.
Parameter or Variable: Dissolved Organic Phosphorus (calculated); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by subtracting the measured phosphate concentrations from the measured total dissolved phosphorus concentrations
Parameter or Variable: DIN:DIP (calculated); Units: molar ratio (unitless); Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by dividing the calculated DIN concentration by the measured phosphate concentration.
Parameter or Variable: DON:DOP (calculated); Units: molar ratio (unitless); Observation Category: laboratory analysis; Sampling Instrument: CTD; Sampling and Analyzing Method: Calculated by dividing the calculated dissolved organic nitrogen concentration by the calculated dissolved organic phosphorus ratio.
Parameter or Variable: DISSOLVED ORGANIC CARBON (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu TOC-Vcph TOC Analyzer; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water column and pore water samples were filtered through a pre-rinsed 0.2 micron cellulose filter and frozen until time of analysis. DOC was measured on a Shimadzu Instruments TOC-Vcph Total Organic Carbon Analyzer with ASI-V Autosampler and TNM Total Nitrogen Analyzer according to the method of Sugimura and Suzuki, 1988.
Parameter or Variable: LATITUDE (measured); Units: decimal degrees; Observation Category: other; Sampling Instrument: shipboard GPS
Parameter or Variable: LONGITUDE (measured); Units: decimal degrees; Observation Category: other; Sampling Instrument: shipboard GPS
Parameter or Variable: Sample depth (measured); Units: meters; Observation Category: in situ; Sampling Instrument: CTD
Parameter or Variable: DEPTH - BOTTOM (measured); Units: meters; Observation Category: in situ; Sampling Instrument: multibeam sonar
Parameter or Variable: Date (measured); Units: mo/day/year; Observation Category: other; Sampling Instrument: none
Parameter or Variable: Local time (measured); Units: hh:mm; Observation Category: other; Sampling Instrument: none; Sampling and Analyzing Method: Time of sample collection in Eastern Daylight Time (UTC-4:00)
Parameter or Variable: redox potential (Eh) (sediments) (measured); Units: mV; Observation Category: laboratory analysis; Sampling Instrument: Eh probe; Sampling and Analyzing Method: Whole sediment Eh was measured during core sectioning.
Parameter or Variable: minimum section depth (sediments) (measured); Units: centimeters below surface (cmbsf); Observation Category: laboratory analysis; Sampling Instrument: ruler; Sampling and Analyzing Method: The distance between sediment-water interface and the top of the sediment core section.
Parameter or Variable: maximum section depth (sediments) (measured); Units: centimeters below surface (cmbsf); Observation Category: laboratory analysis; Sampling Instrument: ruler; Sampling and Analyzing Method: The distance between the sediment-water interface and the bottom of the sediment core section.
Parameter or Variable: section midpoint depth (sediments) (calculated); Units: centimeters below surface (cmbsf); Observation Category: laboratory analysis; Sampling Instrument: ruler; Sampling and Analyzing Method: The distance between the sediment-water interface and the midpoint of the sediment core section, or, the average of the section minimum depth and section maximum depth
Parameter or Variable: total alkalinity (pore water) (measured); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: Pore water was extracted using a manual press. Water was filtered through a 0.2 micron pre-rinsed cellulose filter. Alkalinity was determined using the spectrophotometric method described by Sarazin et al., 1999.
Parameter or Variable: DISSOLVED INORGANIC CARBON (DIC) (pore water) (calculated); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: calculated; Sampling and Analyzing Method: DIC concentrations were calculated from the measured alkalinity values as follows: DIC = Alkalinity * (alpha1 + 2*alpha2) where alpha1 = [HCO3] * [DIC] alpha2 = [CO3] * [DIC] alpha1 and alpha2 were determined using K1 and K2 of carbonic acid dissolution pK1 and pK2 were determined from temperature and salinity according to Luecker et al. 2001: pK1 = 3633.86/T – 61.2172 + 9.67770 * ln(T) – 0.011555 * S + 0.0001152 * S2 pK2 = 471.178/T + 25.9290 – 3.1697 * ln(T) – 0.01781 * S + 0.0001122 * S2
Parameter or Variable: Methane (CH4) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: SRI 8610 GC-FID; Sampling and Analyzing Method: Sediment samples (3 cubic centimeters) were collected into a glass serum vial, preserved with N2-purged 2M NaOH (3 milliliters), crimp-sealed with a butyl rubber stopper and stored at room temperature until analysis. Concentrations were determined by headspace analysis using an SRI 8610C gas chromatograph equipped with a flame ionization detector and SRI Hayesep D 6’x1/8” column (Prod. No. 8600-PKDB). Water column gas samples were collected by overflowing a 1 L PETG bottle and closing headspace-free with a silicone septum cap. A modified 1 L glass media bottle was evacuated to a pressure of 0.2 Torr or below. A 0.7 L aliquot of sample from the PETG was pulled into the evacuated bottle. The 0.7 L sample was shaken and sonicated 3x before the pressure was equilibrated by the addition of brine purged with UHP nitrogen. Extracted gases were collected from the top of the modified media bottle using a syringe and stored in 20 mL serum vials filled with brine. Methane concentrations were determined by injecting gas samples from the brine vials onto an SRI 8610 GC-FID and SRI Hayesep D 6’x1/8” column (Prod. No. 8600-PKDB). See Schmitt, 1991 and Lammers, 1994.
Parameter or Variable: Mean delta 13C of methane (measured); Units: permil; Observation Category: laboratory analysis; Sampling Instrument: Picarro G2201-i CRDS; Sampling and Analyzing Method: Methane isotopic ratios were measured out of the same vials as methane concentrations. 2 mL (sediments) or 5 ml (water column) of headspace from the methane vials (3 cc sediment preserved with 3 mL UHP N2 purged 2 M NaOH for sediments, 20 mL vials of brine for water column) was injected into the Small Sample Introduction Module of the Picarro CRDS.
Parameter or Variable: Standard deviation delta 13C of methane (measured); Units: permil; Observation Category: laboratory analysis; Sampling Instrument: Picarro G2201-i CRDS; Sampling and Analyzing Method: Standard deviation of several measurements taken over the course of 4 minutes by the Picarro G2201-i CRDS.
Parameter or Variable: Hydrogen Sulfide (H2S) (pore water) (measured); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: Pore water was extracted using a manual press. 2 mL unfiltered porewater was collected into a 15 mL centrifuge tube containing 100 uL or 500 uL 20% zinc acetate w/v solution and stored at 5°C until analysis. H2S was determined using the colorimetric method described by Cline, 1969.
Parameter or Variable: Sulfate (SO4 2-) (pore water) (measured); Units: millimoles/liter; Observation Category: laboratory analysis; Sampling Instrument: Dionex Integrion HPIC; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Water was filtered through a pre-rinsed 0.2 micron cellulose filter. Samples were collected in 7 ml glass vials and preserved with 10 ul HNO3 per ml of sample. Samples were diluted for analysis on a Dionex Integrion HPIC with AS-AP autosampler and AS19 guard and analytical columns; Data Quality Method: Data were corrected for analytical bias and for evaporation using the ratio of measured chloride concentration to expected chloride concentration.
Parameter or Variable: Iron II (pore water) (measured); Units: micromole/liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: Pore water was extracted from sediments using a manual press. Pore water was filtered through a pre-rinsed 0.2 micron cellulose filter. Samples were collected in 7 ml glass vials and preserved with 10 ul HNO3 per ml of sample. Iron (II) was measured using the spectrophotometric method described by Stookey, 1970.
Parameter or Variable: Anarobic Methane Oxidation Rate (sediments) (measured); Units: nanomoles per cubic centimeter per day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann-Coulter LS6500; Sampling and Analyzing Method: Live sediment (3 cc) was transferred into a modified Hungate tube with a Hungate stopper and cap on one end and a modified, movable blue butyl chloride stopper at the other end. Three replicates were sampled per depth, with one kill control sampled per core. Kill controls were killed using 2M NaOH. UHP methane was added to samples expected to have high in situ methane concentrations for a target concentration of 15 mM. Samples were injected with 100 microliters of 14C-methane tracer (1 million dpm). Samples were incubated at in situ pressure and temperature for 1-3 days before termination by addition of 3 mL 2 M NaOH. Samples were later transferred to Erlenmeyer flasks, acidified with 5 mL 30% sulfuric acid, and distilled for 6-8 hours. Evolved carbon dioxide was captured using 3-methoxypropylamine and counted on a Beckman-Coulter 6500 liquid scintillation counter. Rates were calculated using the ratio of counted 14C carbon dioxide to the injected tracer activity and the measured in situ methane concentration. Method described in Bowles et al. 2011 and Joye et al. 2004, adapted from Iversen and Blackburn 1981.
Parameter or Variable: Experimental anaerobic methane oxidation rate (sediments) (measured); Units: nanomoles per cubic centimeter per day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann-Coulter LS6500; Sampling and Analyzing Method: Method the same as for Anaerobic Methane Oxidation Rate, except that the added methane (15 mM) plus in situ methane concentration was used in the rate calculation.
Parameter or Variable: Sulfate Reduction Rate (sediments) (measured); Units: nanomoles per cubic centimeter per day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann-Coulter LS6500; Sampling and Analyzing Method: Live sediment (3 cc) was transferred into a modified Hungate tube with a Hungate stopper and cap on one end and a modified, movable blue butyl chloride stopper at the other end. Three replicates were sampled per depth, with one kill control sampled per core. Kill controls were killed using 3 mL 20% zinc acetate. Samples were injected with 100 microliters of 35S sodium sulfate tracer (10 million dpm). Samples were incubated at in situ pressure and temperature for 1-3 days before termination by addition of 3 mL 20% zinc acetate. Samples were later spin down in a centrifuge at 5000 rpm for 2 min twice. The supernatant was subsampled and counted to determine the activity of injected sulfate. Sediments were then distilled in hot hydrochloric acid and reduced chromium chloride (TRIS distillations). Evolved hydrogen sulfide was captured in zinc acetate traps and counted on a Beckman-Coulter 6500 liquid scintillation counter. Rates were calculated using the ratio of captured 35S sulfide to injected sulfate activity, the measured pore water sulfate concentration, and the sediment porosity. Method described in Bowles et al. 2011, and Joye et al. 2004, adapted from Fossing and Jorgensen 1989.
Parameter or Variable: CORE - POROSITY (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: analytical balance; Sampling and Analyzing Method: Sediment samples were collected into glass scintillation vials, capped and stored at 4°C until analysis. Porosity was determined by drying a sample of known mass at 80°C, weighing, and calculating the moisture content.
Parameter or Variable: Sediment organic matter - loss on ignition (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: analytical balance; Sampling and Analyzing Method: Sediment samples were collected into glass scintillation vials, capped and stored at 4°C until analysis. SOM was determined by drying a sample at 80°C, weighing, ashing at 500°C, weighing and calculating weight lost on ignition.
Parameter or Variable: Total Particulate Nitrogen (sediments) (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: ThermoFinnigan FlashEA 1112 series NC Soil Analyzer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was dried at 60°C and then homogenized via grinding. TPN was determined by the method described by Gordan, Jr., 1969 as reproduced by Sharp, 1974. Samples were analyzed on a ThermoFinnigan FlashEA 1112 series NC Soil Analyzer.
Parameter or Variable: CARBON - TOTAL PARTICULATE - SEDIMENT (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: Thermofinnigan FlashEA 1112 series NC Soil Analyzer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was dried at 60°C and then homogenized via grinding. TPC was determined by the method described by Gordan, Jr., 1969 as reproduced by Sharp, 1974. Samples were analyzed on a ThermoFinnigan FlashEA 1112 series NC Soil Analyzer.
Parameter or Variable: PARTICULATE ORGANIC CARBON (sediments) (measured); Units: percent; Observation Category: laboratory analysis; Sampling Instrument: ThermoFinnigan FlashEA 1112 series NC Soil Analyzer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was acidified with 1 N HCl, dried at 60°C, and then homogenized via grinding. POC was determined by the method described by Gordan, Jr., 1969 as reproduced by Sharp, 1974. Samples were analyzed on a ThermoFinnigan FlashEA 1112 series NC Soil Analyzer.
Parameter or Variable: Total particulate phosphate (sediments) (measured); Units: micromole/gram sediment; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu UV1601 spectrophotometer; Sampling and Analyzing Method: A pressed sediment sample (mud-cake, removed from pore water press after extraction) was dried at 80°C, ground, and distributed into 20 mL scintillation vials. The samples were prepared using the method described by Zhou et. al., 2003. TPP and TPP percent were determined using the colormetric method described by Solorzano and Sharp, 1980.
Parameter or Variable: Aerobic Methane Oxidation (water column) (measured); Units: picomoles/liter/day; Observation Category: laboratory analysis; Sampling Instrument: Beckmann Coulter LS6500; Sampling and Analyzing Method: Four technical replicates were collected from each sampled depth by filling 16.6 mL Hungate tubes headspace-free and sealing with exetainer septa. Tubes were stored at 4 °C until injection. One of the four replicates was killed by displacing 1.6 ml sample with 1.6 ml 37% formalin. All samples, including the killed abiotic control, were injected with ~2000000 dpm tritiated methane tracer. Samples were incubated at near-in situ temperature for 1-4 days. Immediately before incubation termination, a 100 ul subsample was removed from each tube and measured on a liquid scintillation counter to determine total dissolved 3H-methane addition. Incubations were terminated by killing with 1.6 ml 37% formalin and purging with air for 1 hour to remove remaining tracer. A 5 ml aliquot of each killed replicate was measured on a liquid scintillation counter to determine the ratio of tracer turnover. The turnover ratio was multiplied by the measured in situ methane concentration to obtain the MOx rate. Killed controls were subtracted and the replicates averaged to obtain the final rate number. See Rogener, 2018
Parameter or Variable: Process Date (measured); Units: mo/day/year; Observation Category: other; Sampling Instrument: none; Sampling and Analyzing Method: Date of sediment core processing

Acquisition Information (collection)
Instrument	bottle CTD multibeam sonar Niskin bottle scintillation counter spectrophotometer Total Organic Carbon (TOC) analyzer
Platform	R/V Atlantis

Last Modified: 2025-05-16T15:37:54Z
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Water column and sediment geochemical data taken by bottle and bottom samples from research vessel Atlantis (cruise AT41) in the southeastern U.S. Atlantic margin from 2018-08-21 to 2018-08-31 (NCEI Accession 0242498)

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