Hope L. Ianiri Pamela L. Campbell Nancy G. Prouty 20250218 comma-delimited text data release DOI:10.5066/P13XVXQC Pacific Coastal and Marine Science Center, Santa Cruz, California U.S. Geological Survey https://doi.org/10.5066/P13XVXQC Hope L. Ianiri Nancy G. Prouty Pamela L. Campbell Amy Gartman Katlin B. Adamczyk Jaycee J. Favela 2025 data release DOI:10.5066/P13XVXQC Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey Suggested Citation: Ianiri, H.L., Prouty, N.G., Campbell, P.L., Gartman, A., Adamczyk, K.B., and Favela, J.J., 2025, Sedimentary organic geochemistry data from Escanaba Trough, off the coast of northern California, collected May-June 2022: U.S. Geological Survey data release, https://doi.org/10.5066/P13XVXQC. https://doi.org/10.5066/P13XVXQC Organic carbon groupings representing different labilities were extracted from sediments collected in the Escanaba Trough from May and June 2022. Organic carbon groups included the total lipid extract and acid insoluble material. These groupings were analyzed for percent total organic carbon (TOC), total nitrogen (TN), stable carbon isotope ratios (d13C), stable nitrogen isotope ratios (d15N) and radiocarbon values (D14C). Percent TOC and TN data was used to calculate the contribution of each organic carbon group to the total organic carbon. Data were obtained to assess organic carbon storage, reactivity, and cycling within sediments of the Escanaba Trough, a hydrothermal spreading center which contains critical minerals. This work aids our understanding of the geochemistry of marine mineral host sediments and hydrothermal vent processes throughout the global ocean. Additional information about the field activity or activities from which these data were derived is available online at: https:// https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-621-FA Escanaba Trough: Exploring the Seafloor and Oceanic Footprints is an interagency effort involving the National Oceanic and Atmospheric Administration, the U.S. Geological Survey, and the Bureau of Ocean Energy Management. Funding is acknowledged from NOAA Ocean Exploration via its Ocean Exploration Fiscal Year 2019 Funding Opportunity and through the National Oceanographic Partnership Program (NOPP), from the USGS Coastal and Marine Hazards and Resources Enhanced Funding Opportunities, and from the Bureau of Ocean Energy Management through Interagency Agreement M19PG00021 with the United States Geological Survey. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 20220531 20220611 Ground condition at time data were collected. Complete None planned -127.53618710 -127.44714953 41.08222461 40.69569198 ISO 19115 Topic Category environment oceans geoscientificInformation Data Categories for Marine Planning Nonliving resources Mineral resources Physical/Chemical features Substrate USGS Thesaurus push coring light stable isotope analysis carbon-14 analysis subsampling geochemistry marine geology Marine Realms Information Bank (MRIB) keywords petroleum resources carbon cycle seep and vent ecosystems chemical analysis sediment geochemistry None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC USGS Metadata Identifier USGS:668f0246d34e4f2ebb745682 Geographic Names Information System (GNIS) Pacific Ocean NGA GEOnet Names Server (GNS) Escanaba Trough No access constraints USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Dyke Andreason at the University of California, Santa Cruz Stable Isotope Laboratory (UCSC SIL) measured ratios of stable isotopes of carbon 13/12 and nitrogen 15/14, total organic carbon, and total nitrogen of the acid insoluble material. Roberta Hansman and Kathy Elder at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) measured ratios of carbon 14/12. Geochemical data are tabulated in comma separated variable (CSV) format. Hope L. Ianiri Pamela L. Campbell Amy Gartman Nancy G. Prouty 2025 Ianiri, H.L., Campbell, P., Gartman, A., and Prouty, N.G., 2025, Characterizing sedimentary organic carbon in a hydrothermal spreading center, the Escanaba Trough: Chemical Geology, https://doi.org/10.1016/j.chemgeo.2025.122679. https://doi.org/10.1016/j.chemgeo.2025.122679 J. L. Morton Robert A. Zierenberg Carol A. Reiss 1994 Morton, J.L., Zierenberg, R.A., Reiss, C.A., 1994. Geologic, hydrothermal, and biologic studies at Escanaba Trough: an introduction, in: Geologic, Hydrothermal, and Biologic Studies at Escanaba Trough, Gorda Ridge, Offshore Northern California. U.S. Geological Survey. David. A. Clague Robert A. Zierenberg Jennifer B. Paduan David W. Caress Brian L. Cousens Brian M. Dreyer Alice S. Davis James McClain Stephanie L. Ross 2022 Clague, D.A., Zierenberg, R.A., Paduan, J.B., Caress, D.W., Cousens, B.L., Dreyer, B.M., Davis, A.S., McClain, J., Ross, S.L., 2022. Emplacement and impacts of lava flows and intrusions on the sediment-buried Escanaba Segment of the Gorda mid-ocean ridge. Journal of Volcanology and Geothermal Research 432, 107701. https://www.sciencedirect.com/science/article/pii/S0377027322002323 E. G. Bligh E. J. Dyer 1959 Bligh E. G., Dyer E. J., 1959. A rapid method of total lipid extraction and purification. Canadian Journal of Biochemistry and Physiology, 37 (8). https://doi.org/10.1139/o59-099 U. M. Hanke L. Wacker N. Haghipour M. W. I. Schmidt T. I. Eglinton C. P. McIntyre 2017 Hanke, U.M., Wacker, L., Haghipour, N., Schmidt, M.W.I., Eglinton, T.I., McIntyre, C.P., 2017. Comprehensive radiocarbon analysis of benzene polycarboxylic acids (BPCAs) derived from pyrogenic carbon in environmental samples. Radiocarbon 59, 1103-1116. https://doi.org/10.1017/RDC.2017.44 Jeomshik Hwang Ellen R. M. Druffel Tomoko Komada 2005 Hwang, J., Druffel, E.R.M., Komada, T., 2005. Transport of organic carbon from the California coast to the slope region: A study of D14C and d13C signatures of organic compound classes. Glob. Biogeochem. Cycles 19. http://doi.wiley.com/10.1029/2004GB002422 Jeomshik Hwang Ellen R. M. Druffel 2005 Hwang, J., Druffel, E.R.M., 2005. Blank Correction for D14C Measurements in Organic Compound Classes of Oceanic Particulate Matter. Radiocarbon 47, 75-87. https://doi.org/10.1017/S0033822200052218 Minze Stuvier Henry A. Polach 1977 Stuiver, M., Polach, H.A., 1977. Discussion Reporting of 14C Data. Radiocarbon 19, 355-363. https://doi.org/10.1017/S0033822200003672 Xu-Chen Wang Ellen R. M. Druffel Cindy Lee 1996 Wang, X.-C., Druffel, E.R.M., Lee, C., 1996. Radiocarbon in organic compound classes in particulate organic matter and sediment in the deep northeast Pacific Ocean. Geophys. Res. Lett. 23, 3583-3586. https://doi.org/10.1029/96GL03423 Analytical precision of stable isotope ratios relative to internationally calibrated in-house reference materials was less than 0.1 per mil for d13C values and 0.2 per mil for d15N values. Precision of total organic carbon was 2.5 micrograms carbon, which corresponds to less than 0.06 percent based on the amounts analyzed. Precision of total nitrogen was less than 0.5 microgram nitrogen, which corresponds to less than 0.003 percent based on the amounts analyzed. 14C measurements at NOSAMS are checked for accuracy via the primary standard NBS Oxalic Acid I (NIST-SRM-4990). Every group of samples processed includes an appropriate blank, analyzed concurrently. Error in D14C values was less than 1.5 per mil. No formal logical accuracy tests were conducted. Dataset is considered complete for the information presented as described in the abstract. Some samples do not have radiocarbon data because this analysis was only performed on a subset of representative samples. Users are advised to read the rest of the metadata record carefully for additional details. The horizontal accuracy for each sample was obtained from the ROV's Ultra Short Baseline Positioning System (USBL) navigation after calibration to the CASIUS (Calibration of Attitude Sensors In USBL Systems) calibration system. Accuracy for this depth is approximately 10- 20 m. The vertical accuracy was determined using multiple DVLs (Doppler Velocity Loggers) on the ROV, which are accurate to less than 1 m. SEDIMENT COLLECTION. Samples were collected aboard the R/V Thomas Thompson via push coring using the ROV Jason. Once recovered shipboard, pore waters were extracted via rhizon samplers, cores were subsectioned into one to five cm slices, the exterior sediment which was in contact with the core liner was removed, and remaining sediment was stored frozen in pre-combusted glass jars. 20220611 ORGANIC CARBON GROUP ISOLATION: Bulk sediments from two depth horizons in each core (surface and near bottom of core) were subsampled for extraction of lipids, acid-soluble (AS), and acid-insoluble (AI) organic matter (Hwang and others , 2005; Wang and others, 1996). Between 500 and 1500 mg of dried sediment was weighed into pre-combusted glass vials. The total lipid extra was extracted using a modified version of the method presented in Bligh and Dyer (1959). Two bed volumes of hexanes were added to each sample and samples were mixed, sonicated for 15 minutes (min), then centrifuged for five min at 2000 revolutions per min. The supernatant was piped to a combusted Turbovap flask. This process was repeated two more times with hexanes and three times with 9:1 DCM:MeOH, combining the supernatant from each sample. Supernatant was dried under N2 gas at 27 degrees Celsius using a TurboVap Evaporation Concentrator (Zymark Corp, NC, USA) until nearly dry, then were transferred to 4 mL vials. The fully dry total lipid extract (TLE) was weighed for each sample. Remaining sediments were subject to acid hydrolysis by adding 6N HCl to each sample, evacuating the headspace with N2 gas, and heating at 110 degrees Celsius for 20 hours. Samples were then mixed, centrifuged at 2200 rpm for five minutes, and supernatant pipetted off to new vial. This process (mixing, centrifuge, and removal of supernatant) was repeated with 1 mL 6N HCl and four 1 mL rinses of MilliQ H2O. The supernatant from all HCl and MilliQ H2O rinses were combined and stored in the freezer (AS fraction). Additional MilliQ H2O was then added to the residual sediments (AI fraction), mixed, centrifuged, and H2O discarded, until pH of pore fluids was about 4. Sediments were then freeze dried. 20230210 RATIOS OF STABLE ISOTOPES OF CARBON 13/12 (d13C), NITROGEN (d15N), TOTAL ORGANIC CARBON, and TOTAL NITROGEN: Acid insoluble material was analyzed for percent TOC, TN, d13C, and d15N using a CE Instruments NC2500 elemental analyzer (EA) coupled to a Thermo Scientific DELTAplus XP isotope ratio mass spectrometer (IRMS) via a Thermo Scientific Conflo III at the University of California at Santa Cruz Stable Isotope Lab. The total lipid extract was measured for TN and d15N at Texas A&M using a Thermo Scientific GC-Isolink EA coupled to a Thermo Scientific Delta V Advantage IRMS. At both labs, measurements were corrected to VPDB (Vienna PeeDee Belemnite) for d13C and AIR for d15N against in-house standard reference material (PUGel at UCSC, USGS 40 and 41a at Texas A&M). The total lipid extract was measured for d13C at NOSAMS via accelerator mass spectrometry (AMS) using a custom built continuous flow AMS. 20240420 Dyke Andreason Stable Isotope Lab at the University of California at Santa Cruz Associate Specialist Mailing

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Santa Cruz CA 95064 831-459-5857 andreasn@ucsc.edu RADIOCARBON ANALYSES: Total lipid extract and acid insoluble material were analyzed for D14C values via accelerator mass spectrometry (AMS) using a custom built continuous flow AMS system at NOSAMS. D14C values were corrected for any addition of carbon during the process step ORGANIC CARBON GROUP ISOLATION by processing 14C modern and depleted grass samples in the same manner as the samples according to Hwang and Druffel (2005) and Hanke and others (2017). 20230420 Roberta Hansman NOSAMS Research Specialist, Staff Chemist mailing and physical

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Woods Hole MA 02543 508-289-2332 nosams@whoi.edu point point 12 0.00000001 0.0000001 Decimal degrees D_WGS_1984 WGS84 6378137.0000 298.2572 EscanabaTrough_organicgeochem_groups.csv Table containing organic carbon group data. producer defined Cruise_ID Lists the alphanumeric cruise identifier for the expedition during which the sample was collected. producer defined TN403 Cruise identification affiliated with Field Activity 2022-621-FA producer defined Sample_ID Name of sample producer defined The sample names include a dive number (J2, denoting Jason2, followed by a number), push core number (PC, denoting push core, followed by a number) and the sediment depth horizon (X-Y). Latitude Latitude of sample in decimal degrees producer defined 40.69572818 41.08224004 decimal degrees 0.00000001 Longitude Longitude of sample in decimal degrees producer defined -127.5282233 -127.4470967 decimal degrees 0.0000001 Water_depth_m Water depth in meters at which the sample was collected. producer defined 3223 3235 meters 1 Location Location where the sample was collected producer defined Central Hill Text descriptor of sampling site as defined in the literature Morton and others (1994), Clague and others (2022) Edifice Rex East Text descriptor of sampling site as defined in the literature Morton and others (1994), Clague and others (2022) SESCA S3A Text descriptor of sampling site as defined in the literature Morton and others (1994), Clague and others (2022) sediment_depth_top_cm top depth of core subsample. Ex: a sediment core slice from 0-1 cm would have a top depth of 0 centimeters and a bottom depth of 1 centimeter. producer defined 0 18 centimeters 1 sediment_depth_bottom_cm bottom depth of core subsample. Ex: a sediment core slice from 0-1 cm would have a top depth of 0 centimeters and a bottom depth of 1 centimeter. producer defined 1 20 centimeters 1 d13C_totalLipidExtract ratio of stable carbon 13/12 isotopes of the total lipid extract producer defined -28.3 -19.0 per mil 0.1 d15N_ totalLipidExtract ratio of stable nitrogen 15/14 isotopes of the total lipid extract producer defined 0.9 5.6 per mil 0.1 D14C_ totalLipidExtract ratio of stable carbon 14/12 isotopes of the total lipid extract. D14C is defined as in Stuiver and Pollach (1977) as the relative difference between the absolute international standard (base year 1950) and sample activity corrected for age and d13C. The value is age corrected to account for decay that took place between collection (or death) of the sample and the time of sample measurement so that measurements of the same sample made years apart will produce the same calculated D14C result. producer defined 0.9 5.6 per mil 0.1 D14C_totalLipidExtract_OS_number NOSAMS accession number NOSAMS Identification number assigned by NOSAMS to each radiocarbon measurement made. TN_totalLipidExtract_percent weight percent of the total lipid extract which is nitrogen. producer defined 0.22 3.47 percent 0.01 OC_totalLipidExtract_proportionoftotal proportion of total sedimentary organic carbon which is represented by the lipid extract. producer defined 1.1 26.3 percent 0.1 N_totalLipidExtract_proportionoftotal proportion of total sedimentary organic nitrogen which is represented by the lipid extract. producer defined 0.1 7.3 percent 0.1 d13C_AcidInsoluble ratio of stable carbon 13/12 isotopes of the acid insoluble material. producer defined -27.9 -24.2 per mil 0.1 d15N_AcidInsoluble ratio of stable nitrogen 15/14 isotopes of the acid insoluble material. producer defined 4.4 7.0 per mil 0.1 D14C_AcidInsoluble ratio of stable carbon 14/12 isotopes of the acid insoluble material. D14C is defined as in Stuiver and Pollach (1977) as the relative difference between the absolute international standard (base year 1950) and sample activity corrected for age and d13C. The value is age corrected to account for decay that took place between collection (or death) of the sample and the time of sample measurement so that measurements of the same sample made years apart will produce the same calculated D14C result. producer defined -999.1 -388.9 per mil 0.1 D14C_AcidInsoluble_OS_number NOSAMS accession number NOSAMS Identification number assigned by NOSAMS to each radiocarbon measurement made. TOC_AcidInsoluble_percent weight percent of the acid insoluble material which is organic carbon. producer defined 0.66 1.47 percent 0.01 TOC_AcidInsoluble_SD standard deviation of duplicate measurements of the weight percent of the acid insoluble material which is organic carbon. Starting from two separate aliquots of bulk material isolated separately and once measured via elemental analyze isotope mass spectrometry at the UCSC-SIL and once measured via accelerator mass spectrometry at NOSAMS. producer defined 0.01 0.46 percent 0.01 TN_AcidInsoluble_percent weight percent of the acid insoluble material which is nitrogen. producer defined 0.05 0.13 percent 0.01 OC_AcidInsoluble_proportionoftotal proportion of total sedimentary organic carbon which is represented by acid insoluble material. producer defined 36.7 127.0 percent 0.1 OC_SD_AcidInsoluble_proportionoftotal standard deviation of duplicate measurements of the proportion of total sedimentary organic carbon which is represented by acid insoluble material. producer defined 1.8 40.0 percent 0.1 N_AcidInsoluble_proportionoftotal proportion of total sedimentary organic carbon which is represented by the acid insoluble material. No associated standard deviation is reported as N data was only measured once. producer defined 24.4 57.0 percent 0.1 OC_AcidSoluble_proportionoftotal proportion of total sedimentary organic carbon which is represented by acid soluble material. Calculated as 100 x proportion_total_OC_AI + proportion_total_OC_TLE. producer defined -48.9 62.2 percent 0.01 N_AcidSoluble_proportionoftotal proportion of total sedimentary organic carbon which is represented by the acid soluble material. Calculated as 100 x proportion_total_ON_AI + proportion_total_ON_TLE. producer defined 42.3 75.5 percent 0.1 The first line of the csv file is a header line. U.S. Geological Survey U.S. Geological Survey - ScienceBase mailing and physical

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov These data are available in a single csv file (EscanabaTrough_organicgeochem_groups.csv). Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. comma-delimited text Microsoft Excel Version 2308 Build 16731.20716 Click-to-Run csv file No compression applied 0.0400 https://www.sciencebase.gov/catalog/file/get/668f0246d34e4f2ebb745682 https://www.sciencebase.gov/catalog/item/668f0246d34e4f2ebb745682 https://doi.org/10.5066/P13XVXQC Data and metadata can be downloaded using the Network_Resource_Name links. The first link is a direct link to download a zipped file of data and metadata. The second link points to a landing page with metadata and data. The third link points to the landing page for the entire data release. None. These data can be viewed with Microsoft Excel or any text reading software. 20250218 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998