http://lod.bco-dmo.org/id/dataset/959765 eng; USA utf8 dataset Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact 2025-04-24 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) Porewater dissolved organic carbon and associated geochemical data for methane seeps in the Cascadia Margin: Astoria Canyon, Barkley Canyon, Hydrate Ridge, and Bullseye Vent 2025-05-21 publication 2025-05-21 revision Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA) 2025-05-21 publication https://doi.org/10.26008/1912/bco-dmo.959765.1 Ellen Lalk United States Geological Survey principalInvestigator Laura L. Lapham University of Maryland Center for Environmental Science principalInvestigator Karen G. Lloyd University of Tennessee Knoxville principalInvestigator Kun Ma Woods Hole Oceanographic Institution principalInvestigator John Pohlman United States Geological Survey principalInvestigator Jeffrey S. Seewald Woods Hole Oceanographic Institution principalInvestigator Rachel Wilson Florida State University principalInvestigator Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. publisher Cite this dataset as: Lalk, E., Pohlman, J., Lapham, L. L., Casso, M., Glenna, M., Hildebrand, A., Lloyd, K. G., Ma, K., Seewald, J. S., Stock, L., Strauss, M. A., Sylva, S., Traver, L., Wilson, R., Williams, L. (2025) Porewater dissolved organic carbon and associated geochemical data for methane seeps in the Cascadia Margin: Astoria Canyon, Barkley Canyon, Hydrate Ridge, and Bullseye Vent. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2025-05-21 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.959765.1 [access date] Cascadia Margin seep DOC and associated geochemical data Dataset Description: &lt;p&gt;The NSF (OCE-2049517) funded ship time, SO4, H2S, DIC, d13C-DIC measurements and partially funded CH4, DOC and d13C-DOC measurements&lt;/p&gt; &lt;p&gt;The DOE NETL interagency agreement with the USGS (#89243320SFE000013) partially funded CH4 measurements&lt;/p&gt; &lt;p&gt;The USGS Mendenhall Research Fellowship Program partially funded DOC and d13C-DOC measurements, and funded TOC and d13C-TOC measurements&lt;/p&gt; Methods and Sampling: &lt;p&gt;Sediment and porewater handling:&lt;/p&gt; &lt;p&gt;PCG02-08- Core material was sectioned and pressure-squeezed with a modified Reeburgh squeezer (Reeburgh, 1967) into acid-washed all-plastic syringes. Porewater was then filtered through 0.45 um polyethersulphone syringe filters.&lt;/p&gt; &lt;p&gt;Hydrates2004- Core material was sectioned and pressure-squeezed with a modified Reeburgh squeezer (Reeburgh, 1967) into acid-washed all-plastic syringes. Porewater was then filtered through 0.2 um arodisc polyethersulphone syringe filters.&lt;/p&gt; &lt;p&gt;AT50-14- Core material was sectioned and pressure-squeezed with a modified Reeburgh squeezer (Reeburgh, 1967) into acid-washed all-plastic syringes. Porewater was then filtered through pre-combusted 0.4 um glass fiber filters.&lt;/p&gt; &lt;p&gt;AT50-29B- Core material was sectioned into acid-washed falcon tubes and refrigerated. Porewater was extracted using Rhizons with a 0.2 um filter size.&lt;/p&gt; &lt;p&gt;Porosity: Fresh sediment was placed in pre-weighed petri-dishes, sealed, and refrigerated until measurement in lab. Petri dishes were weighed upon return to shore, then were played in a drying oven (45℃, 1 week). Petri dishes with dried sediment were weighed again. The difference between the wet and dry sediment is the water weight, and the ratio of the water volume to the total volume is the porosity, assuming a dry bulk density of 2.5.&lt;/p&gt; &lt;p&gt;SO4_mM: 0.5 mL porewater was sub-sampled into 2mL microcentrifuge tubes and dosed with 50 uL 0.1M phosphoric acid. Samples were measured using ion chromatography. IAPSO certified seawater was used for standardization, and precision is ±1.5%.&lt;/p&gt; &lt;p&gt;CH4_uM: Sediment plugs (volume = 3-6 cm3) were sampled and stored in serum bottles sealed with 1-cm-thick butyl rubber septa. 5mL of saturated brine was added to the serum bottles and shaken to equilibrate the headspace. The samples were refrigerated until analysis. For cruises PCG02-08, Hydrates2004, and AT50-14, methane concentrations of serum bottle headspaces were determined by gas chromatography flame ionization detection. These headspace concentrations were used to calculate dissolved concentrations of methane in porewater. For samples measured by GC, dissolved concentrations were calculated following Hoehler et al. (2000).&lt;/p&gt; &lt;p&gt;&amp;nbsp;For cruise AT50-29B, methane concentrations were determined using cavity ringdown spectroscopy. Check standards for concentration were run approximately every 5 samples and corrected as described by Pohlman and others (2021). For samples measured by cavity ring-down spectroscopy, dissolved concentrations were calculated using the following equation:&lt;/p&gt; &lt;p&gt;((pCH4 * 10^-6 * Vg) /&amp;nbsp; (R * T_extraction) + (Vw * pCH4 * 10^-6 *&amp;nbsp; Sol_CH4)) / Vw * 10^6 = [CH4]&lt;/p&gt; &lt;p&gt;Where pCH4 is the headspace concentration of methane in ppm, Vg is the volume of gas sample in mL, R is the gas constant in L-atm/mol-K, T_extraction is the extraction temperature in Kelvin, Vw is the volume of water sample that was extracted in mL, Sol_CH4 is the solubility of methane in mol/L-atm (Wiesenburg &amp;amp; Guinasso, 1979; Yamamoto et al., 1976), and [CH4] is the dissolved concentration of methane in the original natural water sample, in micromoles per liter.&lt;/p&gt; &lt;p&gt;DOC_uM and DOC_d13C_permille: Samples (2-4 mL) were stored in combusted borosilicate glass vials with acid-cleaned teflon-lined septa caps. Vials were pretreated with 20 percent hydrochloric acid (12 microliters per milliliter of sample) to decrease the pH of the sample to 2 or less, and samples were stored at 4 degrees Celsius until analysis. Concentrations were determined with a TOC Analyzer using wet chemical oxidation (cruises PGC02-08 and Hydrates2004) (Heuer et al., 2009; Pohlman et al., 2011) and high temperature catalytic oxidation (cruises AT50-14 and AT50-29B) to convert DOC to CO2. For all cruises, nondispersive infrared detection was used to quantify this CO2. Potassium hydrogen phthalate (KHP) calibration standards were run to quantify DOC concentration. Stable carbon isotopes (d13C-DOC) were measured by isotope ratio mass spectrometry. Stable carbon isotope ratios are reported in standard delta notation relative to Vienna Pee Dee Belemnite (VPDB). Quality assurance included replicate analysis of natural reference materials, field samples and calibration standards. Uncertainty in DOC concentration was 5 percent or less, and uncertainty in d13C was 0.2 permille or less, based on replicate measurements.&lt;/p&gt; &lt;p&gt;DIC_mM and DIC_d13C_permille: Samples for DIC concentration for cruises PCG02-08 and Hydrates2004 were collected as 2 mL aliquots in 5 ml serum vials, sealed with butyl rubber septa, and quantified by coulometry.&amp;nbsp; Samples for stable carbon isotopes (d13C-DIC) for cruises PGC02-08 and Hydrates2004 were collected as 1 ml aliquots in 2 ml serum vials, sealed with butyl rubber septa and analyzed as CO2 by isotope ratio mass spectrometry following acidification of the sample (Pohlman et al., 2013). &amp;nbsp;Samples for DIC concentration and stable carbon isotopes for DIC for cruises AT-50-14 and AT50-29B were collected by injecting 1mL porewater into a helium-filled 12 mL exetainer vial pre-filled with 1mL 85% phosphoric acid. The stable carbon isotope ratios and concentrations were determined from CO2 by isotope ratio mass spectrometry. Measurements are standardized with lithium carbonate reference material, and isotope ratios are reported in the standard d-notation relative to VPDB.&lt;/p&gt; &lt;p&gt;TOC_wt.% and TOC_d13C_permille: Sediment samples from all cruises were freeze-dried and ground with a mortar and pestle. Homogenized sediment was weighed into silver capsules for acid fumigation. Samples were acid fumigated to remove carbonate and dried at 45℃ for 24 hours, then wrapped into tin capsules. Samples were run on an elemental analyzer interfaced with an isotope ratio mass spectrometer. Samples from PGC02-08 were normalized to an acetanilide standard and samples from AT50-14 were run with a peptone reference material, as well as standards USGS 40 226 and USGS 41. Stable carbon isotope values are reported in d notation relative to VPDB.&lt;/p&gt; &lt;p&gt;H2S_mM: Porewater sulfide (ΣH2S) was determined by sparging the sample aliquot after acidification with 25 % phosphoric acid, and trapping evolved H2S in sulfide antioxidant buffer (SAOB) solution for measurement with a sulfide specific electrode. Standards were prepared from a sodium bisulfide stock solution that was titrated with lead nitrate to determine its concentration, daily. Also on a daily basis, the stock solution was serially diluted with SAOB solution to produce a five-level calibration.&lt;/p&gt; Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-2049517 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=2049517 completed Ellen Lalk United States Geological Survey elalk@usgs.gov pointOfContact Laura L. Lapham University of Maryland Center for Environmental Science PO Box 38 Solomons MD 20688-0038 USA lapham@umces.edu pointOfContact Karen G. Lloyd University of Tennessee Knoxville 865-974-3441 M409 Walters Life Sciences Building 1414 West Cumberland Avenue Knoxville TN 37996-0845 USA lloydk@usc.edu pointOfContact Kun Ma Woods Hole Oceanographic Institution kun.ma@whoi.edu pointOfContact John Pohlman United States Geological Survey jpohlman@usgs.gov pointOfContact Jeffrey S. Seewald Woods Hole Oceanographic Institution 508-289-2966 Mail Stop #04 Fye 142A Woods Hole MA 02543 USA jseewald@whoi.edu pointOfContact Rachel Wilson Florida State University 903 West Tennessee St Tallahassee FL 32304-8045 USA rachelyounge@gmail.com pointOfContact asNeeded Dataset Version: 1 Unknown Region Cruise SamplingDate CoreID SampleID CoreType Latitude Longitude WaterDepth_m MidDepth_cmbsf porosity SO4_mM CH4_uM DOC_uM DOC_d13C_permil DIC_mM DIC_d13C_permil TOC_wt_perc TOC_d13C_permil H2S_mM Picarro G2201-i model 5011 UIC Fisons EA-1100 Thermo Flash Shimadzu GC 14 & Agilent 6890 Dionex DX-120 & hermo Scientific Aquion ThermoFinnigan DELTAplus XL ThermoFinnigan Delta S & Delta V Plus AS40 ThermoFinnigan DELTAplus XP GasBench II system OI Analytical 1010 O.I. Analytical Aurora 1030C theme None, User defined region Cruise identfier date core id sample identification sample type latitude longitude depth_w depth core sediment porosity sulfate methane dissolved organic Carbon dissolved inorganic Carbon total organic Carbon H2S featureType BCO-DMO Standard Parameters Cavity enhanced absorption spectrometers CO2 Coulometer Elemental Analyzer Elemental Analyzer Gas Chromatograph Ion Chromatograph Isotope-ratio Mass Spectrometer Isotope-ratio Mass Spectrometer Laboratory Autosampler Mass Spectrometer Thermo-Fisher Scientific Gas Bench II Total Organic Carbon Analyzer Total Organic Carbon Analyzer instrument BCO-DMO Standard Instruments PGC02-08 Hydrates2004 AT50-14 AT50-29 service Deployment Activity otherRestrictions otherRestrictions Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use. Collaborative Research: Investigating the source and flux of dissolved organic carbon released from methane seeps to the deep-ocean https://sites.google.com/umces.edu/thelaphamlab/home/projects/seepdoc Collaborative Research: Investigating the source and flux of dissolved organic carbon released from methane seeps to the deep-ocean <p>NSF Award Abstract:</p> <p>Dissolved organic carbon (DOC) is a key component of the ocean’s food web and carbon cycle, and carbon exchanged between oceanic DOC and the atmosphere has influenced atmospheric CO2 levels on timescales ranging from recent decades to the geologic past. Production by marine algae in the surface ocean is the largest source of DOC and its effects on the ocean carbon cycle are widely appreciated. However, the contribution of DOC from additional sources such as rivers, hydrothermal vents, and methane seeps and their impact on ocean ecology and chemistry are not well understood. Each source differs in terms of its biological utilization and age, which affects the storage and distribution of DOC among the ocean basins. Methane seeps located along continental margins are particularly significant because they may transfer globally significant quantities of carbon stored below the seafloor as natural gas and gas hydrate to the oceans. This project will investigate the production, flux, composition and potential for biological utilization of DOC at Hydrate Ridge, located offshore Oregon. Hydrate Ridge is a prominent methane seep with massive accumulations of gas hydrate and a node of the Ocean Observatories Initiative telecommunications cabled array on the Juan De Fuca tectonic plate, which provides a continuous stream of real-time regional oceanographic data. We will sample and chemically characterize methane, DOC, and other materials to provide information about where the materials originated (deep vs shallow), how they have been chemically altered, to what extent they may feed deep ocean organisms, or contribute to the long term storage of DOC in the ocean. Experiments and analysis will be conducted using sediment cores and bottom water samples collected using either the remotely operated vehicle Jason or the human occupied vehicle Alvin during a 7-day ocean expedition. Additionally, this project will place osmotically-driven pumps on the seafloor to continuously sample fluids for approximately one year, thereby allowing us to monitor the movement of methane and DOC expelled from the seafloor to the ocean and constrain processes that regulate the release of carbon to the oceans at methane seeps. This project will support one graduate student and several undergraduates from a community college in Maryland and a college located in a lower-income urban center in southeastern Massachusetts. We will disseminate project findings to the public with a series of videos for public TV.</p> <p>This study will investigate the production, flux and reactivity of methane-derived dissolved organic carbon (DOC) from methane (CH4) seeps at Hydrate Ridge, Offshore Oregon. The study will address four fundamental questions to determine the significance of CH4-derived DOC within the ocean carbon cycle: (1) How much CH4-derived fossil DOC do seeps contribute to the oceans? (2) To what extent is CH4-derived C incorporated into DOC during anaerobic oxidation of CH4? (3) Is seep DOC bioavailable or recalcitrant when released into the deep ocean? (4) How does the flux of DOC to the water column vary over time? We will employ an interdisciplinary strategy that includes in situ sampling, laboratory incubations, and a comprehensive analytical geochemistry program. Data from the Ocean Observatories Initiative Regional Cabled Array at Southern Hydrate Ridge will be used to provide context for field and experimental data. The composition and abundance of organic and inorganic chemical species along with the stable and radiocarbon isotope composition of pore water, bulk sediment, and water column C pools will be used to identify DOC sources and quantify fluxes from cold seeps characterized by a range of advection rates. The centerpiece of the investigation will be a 7-day research cruise to Hydrate Ridge to collect sediments, pore fluids, and water column samples, and deploy OsmoSamplers for continuous time series fluid sampling. The results will form the foundation for estimating the contribution of CH4-derived DOC to the oceanic DOC pool.</p> <p>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.</p> seepDOM largerWorkCitation project eng; USA oceans -126.849944 -124.6027 44.568359 48.671875 2002-10-05 2024-08-22 Astoria Canyon and Hydrate Ridge 0 BCO-DMO catalogue of parameters from Porewater dissolved organic carbon and associated geochemical data for methane seeps in the Cascadia Margin: Astoria Canyon, Barkley Canyon, Hydrate Ridge, and Bullseye Vent Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact http://lod.bco-dmo.org/id/dataset-parameter/962272.rdf Name: Region Units: unitless Description: <p>General sampling location within the Cascadia Margin (Astoria Canyon, Barkley Canyon, Hydrate Ridge, Bullseye Vent)</p> http://lod.bco-dmo.org/id/dataset-parameter/962273.rdf Name: Cruise Units: unitless Description: <p>Cruise ID for sample collection</p> http://lod.bco-dmo.org/id/dataset-parameter/962274.rdf Name: SamplingDate Units: yyyy-mm-dd Description: <p>Date the sample was collected</p> http://lod.bco-dmo.org/id/dataset-parameter/962275.rdf Name: CoreID Units: unitless Description: <p>Core ID. Core IDs are specific letter and number combinations given to cores when collected, and are specific to each individual cruise</p> http://lod.bco-dmo.org/id/dataset-parameter/962276.rdf Name: SampleID Units: unitless Description: <p>Sample ID. Sample IDs are numbers given to each sediment sub-sample when collected, and are specific to each individual cruise</p> http://lod.bco-dmo.org/id/dataset-parameter/962277.rdf Name: CoreType Units: unitless Description: <p>Core type (seep= collected in a methane seep, reference = collected outside a methane seep)</p> http://lod.bco-dmo.org/id/dataset-parameter/962278.rdf Name: Latitude Units: decimal degrees Description: <p>Sample latitude, south is negative</p> http://lod.bco-dmo.org/id/dataset-parameter/962279.rdf Name: Longitude Units: decimal degrees Description: <p>Sample longitude, west is negative</p> http://lod.bco-dmo.org/id/dataset-parameter/962280.rdf Name: WaterDepth_m Units: meters (m) Description: <p>Depth of the seafloor relative to the sea surface at the sample location</p> http://lod.bco-dmo.org/id/dataset-parameter/962281.rdf Name: MidDepth_cmbsf Units: centimeters below sea floor (cmbsf) Description: <p>Mid-depth of core sub-section relative to the sediment water interface</p> http://lod.bco-dmo.org/id/dataset-parameter/962282.rdf Name: porosity Units: unitless Description: <p>Sediment water content relative to solid material</p> http://lod.bco-dmo.org/id/dataset-parameter/962283.rdf Name: SO4_mM Units: millimolar (mM) Description: <p>Pore water dissolved sulfate</p> http://lod.bco-dmo.org/id/dataset-parameter/962284.rdf Name: CH4_uM Units: micromolar (uM) Description: <p>Pore water dissolved methane</p> http://lod.bco-dmo.org/id/dataset-parameter/962285.rdf Name: DOC_uM Units: micromolar (uM) Description: <p>Pore water dissolved organic carbon</p> http://lod.bco-dmo.org/id/dataset-parameter/962286.rdf Name: DOC_d13C_permil Units: per mille (‰) Description: <p>Bulk stable carbon isotope value of pore water dissolved organic carbon relative to Vienna Pee Dee Belemnite (VPDB)</p> http://lod.bco-dmo.org/id/dataset-parameter/962287.rdf Name: DIC_mM Units: millimolar (mM) Description: <p>Porewater dissolved inorganic carbon</p> http://lod.bco-dmo.org/id/dataset-parameter/962288.rdf Name: DIC_d13C_permil Units: per mille (‰) Description: <p>Bulk stable carbon isotope value of porewater dissolved inorganic carbon relative to Vienna Pee Dee Belemnite (VPDB)</p> http://lod.bco-dmo.org/id/dataset-parameter/962289.rdf Name: TOC_wt_perc Units: weight percent (wt.%) Description: <p>sediment total organic carbon content</p> http://lod.bco-dmo.org/id/dataset-parameter/962290.rdf Name: TOC_d13C_permil Units: per mille (‰) Description: <p>Bulk stable carbon isotope value of sediment total organic carbon content relative to Vienna Pee Dee Belemnite (VPDB)</p> http://lod.bco-dmo.org/id/dataset-parameter/962291.rdf Name: H2S_mM Units: millimolar (mM) Description: <p>Pore water dissolved sulfide</p> GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact 15831 https://darchive.mblwhoilibrary.org/server/api/core/bitstreams/88761f79-f298-4998-9dc7-d45681694ba1/content download https://doi.org/10.26008/1912/bco-dmo.959765.1 download onLine dataset &lt;p&gt;Sediment and porewater handling:&lt;/p&gt; &lt;p&gt;PCG02-08- Core material was sectioned and pressure-squeezed with a modified Reeburgh squeezer (Reeburgh, 1967) into acid-washed all-plastic syringes. Porewater was then filtered through 0.45 um polyethersulphone syringe filters.&lt;/p&gt; &lt;p&gt;Hydrates2004- Core material was sectioned and pressure-squeezed with a modified Reeburgh squeezer (Reeburgh, 1967) into acid-washed all-plastic syringes. Porewater was then filtered through 0.2 um arodisc polyethersulphone syringe filters.&lt;/p&gt; &lt;p&gt;AT50-14- Core material was sectioned and pressure-squeezed with a modified Reeburgh squeezer (Reeburgh, 1967) into acid-washed all-plastic syringes. Porewater was then filtered through pre-combusted 0.4 um glass fiber filters.&lt;/p&gt; &lt;p&gt;AT50-29B- Core material was sectioned into acid-washed falcon tubes and refrigerated. Porewater was extracted using Rhizons with a 0.2 um filter size.&lt;/p&gt; &lt;p&gt;Porosity: Fresh sediment was placed in pre-weighed petri-dishes, sealed, and refrigerated until measurement in lab. Petri dishes were weighed upon return to shore, then were played in a drying oven (45℃, 1 week). Petri dishes with dried sediment were weighed again. The difference between the wet and dry sediment is the water weight, and the ratio of the water volume to the total volume is the porosity, assuming a dry bulk density of 2.5.&lt;/p&gt; &lt;p&gt;SO4_mM: 0.5 mL porewater was sub-sampled into 2mL microcentrifuge tubes and dosed with 50 uL 0.1M phosphoric acid. Samples were measured using ion chromatography. IAPSO certified seawater was used for standardization, and precision is ±1.5%.&lt;/p&gt; &lt;p&gt;CH4_uM: Sediment plugs (volume = 3-6 cm3) were sampled and stored in serum bottles sealed with 1-cm-thick butyl rubber septa. 5mL of saturated brine was added to the serum bottles and shaken to equilibrate the headspace. The samples were refrigerated until analysis. For cruises PCG02-08, Hydrates2004, and AT50-14, methane concentrations of serum bottle headspaces were determined by gas chromatography flame ionization detection. These headspace concentrations were used to calculate dissolved concentrations of methane in porewater. For samples measured by GC, dissolved concentrations were calculated following Hoehler et al. (2000).&lt;/p&gt; &lt;p&gt;&amp;nbsp;For cruise AT50-29B, methane concentrations were determined using cavity ringdown spectroscopy. Check standards for concentration were run approximately every 5 samples and corrected as described by Pohlman and others (2021). For samples measured by cavity ring-down spectroscopy, dissolved concentrations were calculated using the following equation:&lt;/p&gt; &lt;p&gt;((pCH4 * 10^-6 * Vg) /&amp;nbsp; (R * T_extraction) + (Vw * pCH4 * 10^-6 *&amp;nbsp; Sol_CH4)) / Vw * 10^6 = [CH4]&lt;/p&gt; &lt;p&gt;Where pCH4 is the headspace concentration of methane in ppm, Vg is the volume of gas sample in mL, R is the gas constant in L-atm/mol-K, T_extraction is the extraction temperature in Kelvin, Vw is the volume of water sample that was extracted in mL, Sol_CH4 is the solubility of methane in mol/L-atm (Wiesenburg &amp;amp; Guinasso, 1979; Yamamoto et al., 1976), and [CH4] is the dissolved concentration of methane in the original natural water sample, in micromoles per liter.&lt;/p&gt; &lt;p&gt;DOC_uM and DOC_d13C_permille: Samples (2-4 mL) were stored in combusted borosilicate glass vials with acid-cleaned teflon-lined septa caps. Vials were pretreated with 20 percent hydrochloric acid (12 microliters per milliliter of sample) to decrease the pH of the sample to 2 or less, and samples were stored at 4 degrees Celsius until analysis. Concentrations were determined with a TOC Analyzer using wet chemical oxidation (cruises PGC02-08 and Hydrates2004) (Heuer et al., 2009; Pohlman et al., 2011) and high temperature catalytic oxidation (cruises AT50-14 and AT50-29B) to convert DOC to CO2. For all cruises, nondispersive infrared detection was used to quantify this CO2. Potassium hydrogen phthalate (KHP) calibration standards were run to quantify DOC concentration. Stable carbon isotopes (d13C-DOC) were measured by isotope ratio mass spectrometry. Stable carbon isotope ratios are reported in standard delta notation relative to Vienna Pee Dee Belemnite (VPDB). Quality assurance included replicate analysis of natural reference materials, field samples and calibration standards. Uncertainty in DOC concentration was 5 percent or less, and uncertainty in d13C was 0.2 permille or less, based on replicate measurements.&lt;/p&gt; &lt;p&gt;DIC_mM and DIC_d13C_permille: Samples for DIC concentration for cruises PCG02-08 and Hydrates2004 were collected as 2 mL aliquots in 5 ml serum vials, sealed with butyl rubber septa, and quantified by coulometry.&amp;nbsp; Samples for stable carbon isotopes (d13C-DIC) for cruises PGC02-08 and Hydrates2004 were collected as 1 ml aliquots in 2 ml serum vials, sealed with butyl rubber septa and analyzed as CO2 by isotope ratio mass spectrometry following acidification of the sample (Pohlman et al., 2013). &amp;nbsp;Samples for DIC concentration and stable carbon isotopes for DIC for cruises AT-50-14 and AT50-29B were collected by injecting 1mL porewater into a helium-filled 12 mL exetainer vial pre-filled with 1mL 85% phosphoric acid. The stable carbon isotope ratios and concentrations were determined from CO2 by isotope ratio mass spectrometry. Measurements are standardized with lithium carbonate reference material, and isotope ratios are reported in the standard d-notation relative to VPDB.&lt;/p&gt; &lt;p&gt;TOC_wt.% and TOC_d13C_permille: Sediment samples from all cruises were freeze-dried and ground with a mortar and pestle. Homogenized sediment was weighed into silver capsules for acid fumigation. Samples were acid fumigated to remove carbonate and dried at 45℃ for 24 hours, then wrapped into tin capsules. Samples were run on an elemental analyzer interfaced with an isotope ratio mass spectrometer. Samples from PGC02-08 were normalized to an acetanilide standard and samples from AT50-14 were run with a peptone reference material, as well as standards USGS 40 226 and USGS 41. Stable carbon isotope values are reported in d notation relative to VPDB.&lt;/p&gt; &lt;p&gt;H2S_mM: Porewater sulfide (ΣH2S) was determined by sparging the sample aliquot after acidification with 25 % phosphoric acid, and trapping evolved H2S in sulfide antioxidant buffer (SAOB) solution for measurement with a sulfide specific electrode. Standards were prepared from a sodium bisulfide stock solution that was titrated with lead nitrate to determine its concentration, daily. Also on a daily basis, the stock solution was serially diluted with SAOB solution to produce a five-level calibration.&lt;/p&gt; Specified by the Principal Investigator(s) &lt;p&gt;Sampling for this dataset includes push-coring, video-guided multi-coring, and piston coring. Samples from cruise PGC02-08 were collected by piston coring, and horizontal positioning information for cores was achieved with an acoustic bottom transponder constellation, which provided an accuracy of 1-2 meters. Samples from cruise Hydrates2004 were collected by push-coring using the ROV ROPOS. Samples from cruise AT50-14&amp;nbsp;were collected by push-coring using the HOV Alvin, and by video-guided multi-coring (sample IDs containing ‘MUC’). Samples from cruise AT50-29B were collected by push-coring using the ROV Jason.&lt;/p&gt; &lt;p&gt;SO4_mM: For cruises PGC02-08 and Hydrates2004 sulfate was measured using a Dionex DX-120 ion chromatograph equipped with a 4 mm AS-9HC column.&amp;nbsp; For cruises AT50-14 and AT50-29B sulfate was measured with a Thermo Scientific Aquion ion chromatograph (IonPac AG22 4x50 mm guard column, IonPac AS22 4x250 mm analytical column, and AERS 300 4 mm suppressor) with an AS40 Autosampler.&lt;/p&gt; &lt;p&gt;CH4_uM: For cruises PGC02-08 and Hydrates2004 methane was measured by gas chromatography using a Shimadzu GC 14-A and flame-ionization detector.&amp;nbsp; For cruise AT50-14 samples were measured using an Agilent 6890 Gas Chromatograph with a Flame Ionization Detector and fitted with a HaySep Q packed column, 1/8”, 80/100 Mesh, 6ft long, operated at a constant flow of 20 ml/min. Samples were injected with a modified sample loop. For samples from AT50-29B, a Picarro G2201-i CRDS was used.&amp;nbsp;&lt;/p&gt; &lt;p&gt;DOC_uM and DOC_d13C_permille: For cruises PGC02-08 and Hydrates2004 samples were measured on an OI Analytical 1010 TOC analyzer with a nondispersive infrared detector interfaced to a ThermoFinnigan DELTAplus XP mass spectrometer. For cruises AT50-14 and AT50-29B DOC samples were analyzed on an O.I. Analytical Aurora 1030C auto-analyzer by high temperature catalytic oxidation and quantified with a nondispersive infrared detector. d13C-DOC values were quantified using a ThermoFinnigan DELTAplus XL Isotope Ratio Mass Spectrometer interfaced to the Aurora 1030C following the method of Lalonde and others (2014).&lt;/p&gt; &lt;p&gt;DIC_mM and DIC_d13C_permille: For cruises PGC02-08 and Hydrates2004 DIC concentrations were determined using a model 5011 UIC carbon dioxide coulometer, and stable carbon isotope ratios were determined using a ThermoFinnigan Delta S isotope ratio mass spectrometer. &amp;nbsp;For cruises AT50-14 and AT50-29B, DIC concentrations and carbon isotope values measured using a GasBench II system interfaced with a Delta V Plus isotope ratio mass spectrometer at the University of California Davis Stable Isotope Facility.&lt;/p&gt; &lt;p&gt;TOC_wt.% and TOC_d13C_permille: For cruise PGC02-08, TOC content and carbon isotope values were quantified using a Fisons EA-1100 Elemental Analyzer interfaces to a ThermoFinnigan Delta Plus XP isotope ratio mass spectrometer. For cruise AT50-14, TOC content and carbon isotope values were quantified using a Thermo Flash Elemental Analyzer interfaced with a Delta V Plus isotope ratio mass spectrometer at the Alaska Stable Isotope Facility.&lt;/p&gt; &lt;p&gt;H2S_mM: Sulfide was measured with a Cole-Parmer Silver/Sulfide Ion-Selective Electrode (27502-41)&lt;/p&gt; Specified by the Principal Investigator(s) asNeeded 7.x-1.1 Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact Picarro G2201-i Picarro G2201-i PI Supplied Instrument Name: Picarro G2201-i PI Supplied Instrument Description:CH4-  Picarro G2201-i Cavity ringdown spectroscopy Instrument Name: Cavity enhanced absorption spectrometers Instrument Short Name:CEAS Instrument Description: Instruments that illuminate a sample inside an optical cavity, typically using laser light, and measure the concentration or amount of a species in gas phase by absorption spectroscopy. Techniques include cavity ring-down spectroscopy (CRDS) and integrated cavity output spectroscopy (ICOS). model 5011 UIC model 5011 UIC PI Supplied Instrument Name: model 5011 UIC PI Supplied Instrument Description:DIC_mM and DIC_d13C_permille: For cruises PGC02-08 and Hydrates2004 DIC concentrations were determined using a model 5011 UIC carbon dioxide coulometer, Instrument Name: CO2 Coulometer Instrument Short Name:CO2 coulometer Instrument Description: A CO2 coulometer semi-automatically controls the sample handling and extraction of CO2 from seawater samples. Samples are acidified and the CO2 gas is bubbled into a titration cell where CO2 is converted to hydroxyethylcarbonic acid which is then automatically titrated with a coulometrically-generated base to a colorimetric endpoint. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB12 Fisons EA-1100 Fisons EA-1100 PI Supplied Instrument Name: Fisons EA-1100 PI Supplied Instrument Description:TOC_wt.% and TOC_d13C_permille: For cruise PGC02-08, TOC content and carbon isotope values were quantified using a Fisons EA-1100 Elemental Analyzer interfaces to a ThermoFinnigan Delta Plus XP isotope ratio mass spectrometer. Instrument Name: Elemental Analyzer Instrument Short Name: Instrument Description: Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB01/ Thermo Flash Thermo Flash PI Supplied Instrument Name: Thermo Flash PI Supplied Instrument Description:TOC_wt.% and TOC_d13C_permille: For cruise AT50-14, TOC content and carbon isotope values were quantified using a Thermo Flash Elemental Analyzer interfaced with a Delta V Plus isotope ratio mass spectrometer at the Alaska Stable Isotope Facility. Instrument Name: Elemental Analyzer Instrument Short Name: Instrument Description: Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB01/ Shimadzu GC 14 & Agilent 6890 Shimadzu GC 14 & Agilent 6890 PI Supplied Instrument Name: Shimadzu GC 14 & Agilent 6890 PI Supplied Instrument Description:CH4_uM: For cruises PGC02-08 and Hydrates2004 methane was measured by gas chromatography using a Shimadzu GC 14-A and flame-ionization detector.  For cruise AT50-14 samples were measured using an Agilent 6890 Gas Chromatograph with a Flame Ionization Detector and fitted with a HaySep Q packed column, 1/8”, 80/100 Mesh, 6ft long, operated at a constant flow of 20 ml/min. Samples were injected with a modified sample loop. For samples from AT50-29B, a Picarro G2201-i CRDS was used.  Instrument Name: Gas Chromatograph Instrument Short Name:Gas Chromatograph Instrument Description: Instrument separating gases, volatile substances, or substances dissolved in a volatile solvent by transporting an inert gas through a column packed with a sorbent to a detector for assay. (from SeaDataNet, BODC) Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB02/ Dionex DX-120 & hermo Scientific Aquion Dionex DX-120 & hermo Scientific Aquion PI Supplied Instrument Name: Dionex DX-120 & hermo Scientific Aquion PI Supplied Instrument Description:For cruises PGC02-08 and Hydrates2004 sulfate was measured using a Dionex DX-120 ion chromatograph equipped with a 4 mm AS-9HC column.  For cruises AT50-14 and AT50-29B sulfate was measured with a Thermo Scientific Aquion ion chromatograph (IonPac AG22 4x50 mm guard column, IonPac AS22 4x250 mm analytical column, and AERS 300 4 mm suppressor) with an AS40 Autosampler. Instrument Name: Ion Chromatograph Instrument Short Name:Ion Chromatograph Instrument Description: Ion chromatography is a form of liquid chromatography that measures concentrations of ionic species by separating them based on their interaction with a resin. Ionic species separate differently depending on species type and size. Ion chromatographs are able to measure concentrations of major anions, such as fluoride, chloride, nitrate, nitrite, and sulfate, as well as major cations such as lithium, sodium, ammonium, potassium, calcium, and magnesium in the parts-per-billion (ppb) range. (from http://serc.carleton.edu/microbelife/research_methods/biogeochemical/ic.html) ThermoFinnigan DELTAplus XL ThermoFinnigan DELTAplus XL PI Supplied Instrument Name: ThermoFinnigan DELTAplus XL PI Supplied Instrument Description:DOC_uM and DOC_d13C_permille: For cruises AT50-14 and AT50-29B DOC, d13C-DOC values were quantified using a ThermoFinnigan DELTAplus XL Isotope Ratio Mass Spectrometer interfaced to the Aurora 1030C following the method of Lalonde and others (2014). Instrument Name: Isotope-ratio Mass Spectrometer Instrument Short Name:IR Mass Spec; IRMS Instrument Description: The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer). Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/ ThermoFinnigan Delta S & Delta V Plus ThermoFinnigan Delta S & Delta V Plus PI Supplied Instrument Name: ThermoFinnigan Delta S & Delta V Plus PI Supplied Instrument Description:DIC_mM and DIC_d13C_permille: For cruises PGC02-08 and Hydrates2004 DIC concentrations were determined using a model 5011 UIC carbon dioxide coulometer, and stable carbon isotope ratios were determined using a ThermoFinnigan Delta S isotope ratio mass spectrometer.  For cruises AT50-14 and AT50-29B, DIC concentrations and carbon isotope values measured using a GasBench II system interfaced with a Delta V Plus isotope ratio mass spectrometer at the University of California Davis Stable Isotope Facility. Instrument Name: Isotope-ratio Mass Spectrometer Instrument Short Name:IR Mass Spec; IRMS Instrument Description: The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer). Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/ AS40 AS40 PI Supplied Instrument Name: AS40 PI Supplied Instrument Description:For cruises AT50-14 and AT50-29B sulfate was measured with a Thermo Scientific Aquion ion chromatograph (IonPac AG22 4x50 mm guard column, IonPac AS22 4x250 mm analytical column, and AERS 300 4 mm suppressor) with an AS40 Autosampler. Instrument Name: Laboratory Autosampler Instrument Short Name: Instrument Description: Laboratory apparatus that automatically introduces one or more samples with a predetermined volume or mass into an analytical instrument. ThermoFinnigan DELTAplus XP ThermoFinnigan DELTAplus XP PI Supplied Instrument Name: ThermoFinnigan DELTAplus XP PI Supplied Instrument Description:DOC_uM and DOC_d13C_permille: For cruises PGC02-08 and Hydrates2004 samples were measured on an OI Analytical 1010 TOC analyzer with a nondispersive infrared detector interfaced to a ThermoFinnigan DELTAplus XP mass spectrometer. Instrument Name: Mass Spectrometer Instrument Short Name:Mass Spec Instrument Description: General term for instruments used to measure the mass-to-charge ratio of ions; generally used to find the composition of a sample by generating a mass spectrum representing the masses of sample components. Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/ GasBench II system GasBench II system PI Supplied Instrument Name: GasBench II system PI Supplied Instrument Description:DIC- GasBench II system interfaced with a Delta V Plus isotope ratio mass spectrometer Instrument Name: Thermo-Fisher Scientific Gas Bench II Instrument Short Name:GasBench II Instrument Description: An on-line gas preparation and introduction system for isotope ratio mass spectrometry that is designed for high precision isotope and molecular ratio determination of headspace samples, including water equilibration, carbonates and atmospheric gases. The instrument allows for the use of a dual viscous flow inlet system of repetitive measurements of sample and standard gas on a continuous flow isotope ratio mass spectrometer (CF-IRMS) system. The sample volume is the sample vial (instead of a metal bellows), and the reference gas volume is a pressurized gas tank. The instrument consists of a user programmable autosampler, a gas sampling system, a maintenance-free water removal system, a loop injection system, an isothermal gas chromatograph (GC), an active open split interface, a reference gas injection system with three reference ports, and one or two optional LN2 traps for cryofocusing. The gas sampling system includes a two port needle which adds a gentle flow of He into the sample vial, diluting and displacing sample gas. Water is removed from the sample gas through diffusion traps. The loop injector aliquots the sample gas onto the GC column, which separates the molecular species. The reference gas injection system allows accurate referencing of each sample aliquot to isotopic standards. The system can be used with several options including a carbonate reaction kit that allows injection of anhydrous phospohric acid into sample vials. Note "Finnigan GasBench-II" is the previous brand name of this instrument. OI Analytical 1010 OI Analytical 1010 PI Supplied Instrument Name: OI Analytical 1010 PI Supplied Instrument Description:DOC_uM and DOC_d13C_permille: For cruises PGC02-08 and Hydrates2004 samples were measured on an OI Analytical 1010 TOC analyzer with a nondispersive infrared detector interfaced to a ThermoFinnigan DELTAplus XP mass spectrometer. Instrument Name: Total Organic Carbon Analyzer Instrument Short Name:TOC analyzer Instrument Description: A unit that accurately determines the carbon concentrations of organic compounds typically by detecting and measuring its combustion product (CO2). See description document at: http://bcodata.whoi.edu/LaurentianGreatLakes_Chemistry/bs116.pdf Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB04/ O.I. Analytical Aurora 1030C O.I. Analytical Aurora 1030C PI Supplied Instrument Name: O.I. Analytical Aurora 1030C PI Supplied Instrument Description:DOC- O.I. Analytical Aurora 1030C Instrument Name: Total Organic Carbon Analyzer Instrument Short Name:TOC analyzer Instrument Description: A unit that accurately determines the carbon concentrations of organic compounds typically by detecting and measuring its combustion product (CO2). See description document at: http://bcodata.whoi.edu/LaurentianGreatLakes_Chemistry/bs116.pdf Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB04/ Cruise: PGC02-08 PGC02-08 Community Standard Description International Council for the Exploration of the Sea CCGS John P. Tully vessel PGC02-08 Bob MacDonald University of Victoria Cruise: Hydrates2004 Hydrates2004 Community Standard Description International Council for the Exploration of the Sea CCGS John P. Tully vessel Hydrates2004 Ross Chapman University of Victoria Cruise: AT50-14 AT50-14 R/V Atlantis Community Standard Description International Council for the Exploration of the Sea R/V Atlantis vessel AT50-14 Laura L. Lapham University of Maryland Center for Environmental Science Cruise: AT50-29 AT50-29 R/V Atlantis Community Standard Description International Council for the Exploration of the Sea R/V Atlantis vessel AT50-29 Michael Vardaro University of Washington Community Standard Description International Council for the Exploration of the Sea CCGS John P. Tully vessel R/V Atlantis Community Standard Description International Council for the Exploration of the Sea R/V Atlantis vessel