Hope L. Ianiri Katlin B. Adamczyk Jaycee J. Favela Amy Gartman 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., Campbell, P.L., Gartman, A., Prouty, N.G., 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 Nutrients were measured from porewaters of sediment within the Escanaba Trough, a hydrothermal spreading center. Location information (latitude, longitude, and depth) is also reported. Data were obtained as part of a project to assess the geochemistry of Escanaba Trough sediments, 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 Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 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. 20220531 20220611 Ground condition at time samples were collected. Complete None planned -127.53618710 -127.44714953 41.08223904 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 subsampling geochemistry marine geology Marine Realms Information Bank (MRIB) keywords petroleum resources carbon cycle seep and vent ecosystems nutrient measurements 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:6696d303d34ecb78f609f6e6 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 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 Analytical precision was 5 percent for all analytes. Results not determined due to a chemical interference with other components of the porewater are reported as -9999 while results below the detection limit are reported as -8888. The detection limits were as follows: PO4: 0.1, Si(OH)4: 1.0, NO2: 0.1, NO2_plus_NO3: 0.2, NH4: 0.2 The measured value of NO2 plus NO3 could not be greater than the measured value of NO2 alone. Dataset is considered complete for the information presented as described in the abstract. Not ever sample has data for every nutrient as some nutrient concentrations were below the limit of detection. 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. POREWATER COLLECTION. Samples were collected via push coring using the ROV Jason and R/V Thomas Thompson. Once recovered shipboard, pore waters were extracted via rhizon samplers with an inline filter pore size 0.15 micrometers attached to a syringe. Pore waters were transferred to centrifuge tubes and stored frozen until analysis. 20220611 MEASUREMENT OF POREWATER NUTRIENTS: Nitrite, nitrate plus nitrite, phosphate, silicic acid, and ammonium were measured via flow injection analysis using a Lachet Instruments QuikChem 8500 Series 2 Flow Injection Analysis System. 20240301 Ken Marchus Analytical Lab of the University of California, Santa Barbara Marine Science Institute Lab Manager Mailing

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Santa Barbara CA 93106 805-893-3802 k_a_m@ucsb.edu point point 241 0.00000001 0.0000001 Decimal degrees D_WGS_1984 WGS84 6378137.0000 298.2572 EscanabaTrough_nutrients.csv Table of nutrient 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) and 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 40.69569198 41.08223904 decimal degrees 0.00000001 Longitude Longitude of sample in decimal degrees producer defined -127.5361871 -127.4471495 decimal degrees 0.0000001 Water_depth_m Water depth in meters at which the sample was collected. producer defined 3222 3290 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 West 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) SESCA Waypoint 2 S2A Text descriptor of sampling site as defined in the literature Morton and others (1994), Clague and others (2022) SESCA Unnamed & North Hill Text descriptor of sampling site as defined in the literature Morton and others (1994), Clague and others (2022) MESCA 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 0.0 24.5 centimeters 0.1 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 22 centimeters 1 P04_uM concentration of phosphate in pore waters. A value of -8888 indicates concentration was below detection limit. producer defined 0.3 22.0 micromolar 0.1 Si_OH4_uM concentration of silicic acid in pore waters producer defined 131 595 micromolar 1.0 NO2_uM concentration of nitrite in pore waters. A value of -9999 indicates concentration was not determined and a value of -8888 indicates concentration was below detection limit. producer defined 0.1 21.9 micromolar 0.1 NO2_plus_NO3_uM concentration of nitrite and nitrate in pore waters. A value of -9999 indicates concentration was not determined and a value of -8888 indicates concentration was below detection limit. producer defined 0.4 58.8 micromolar 0.1 NH4_uM concentration of ammonium in pore waters. A value of -8888 indicates concentration was below detection limit. producer defined 0.2 2121.0 micromolar 0.1 NO3_uM concentration of nitrate in pore waters. Calculated as nitrite + nitrate concentration (attribute NO2_plus_NO3) minus nitrite concentration (attribute NO2). A value of -9999 indicates concentration was not determined and a value of -8888 indicates concentration was below detection limit. producer defined 0.1 54.8 micromolar 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_nutrients.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 0.048 https://www.sciencebase.gov/catalog/file/get/6696d303d34ecb78f609f6e6 https://www.sciencebase.gov/catalog/item/6696d303d34ecb78f609f6e6 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