bcodmo_dataset_986866_v1 eng UTF8 dataset service Adam Shepherd BCO-DMO 508-289-2772 266 Woods Hole Rd. MS#36 Woods Hole MA 02543 USA erddap@bco-dmo.org pointOfContact 2026-04-08 ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) 3 column row temporal [Water column methane, methane oxidation, and pmoA gene copies] - Water column methane, methane oxidation, and pmoA gene copies above southern California methane seeps determined from samples collected on R/V Atlantis cruise AT50-12 in July 2023 (Collaborative Research: Redefining the footprint of deep ocean methane seepage for benthic ecosystems) 2026-04-08 creation erddap.bco-dmo.org bcodmo_dataset_986866_v1 BCO-DMO info@bco-dmo.org https://osprey.bco-dmo.org/dataset/986866 information web browser Background Information Background information from the source information originator Marine methane (CH₄) seeps are dynamic biogeochemical systems that modulate carbon cycling and support high-biomass communities through microbial methane (CH₄) oxidation. While most CH₄ is consumed anaerobically in sediments, a fraction enters the water column, where aerobic methanotrophs form a biological filter limiting CH₄ flux to the atmosphere. However, the extent to which this microbial activity and CH₄ influence extend beyond visibly active seep zones remains poorly constrained, with implications for deep-sea food webs, biogeochemical gradients, and carbon cycling. We investigated CH₄ dynamics and methanotroph distribution across three seep sites on the Southern California margin (Del Mar, Santa Monica (800 meters) Mound, Lasuen Knoll; ~400–1200 meters depth). Using radiotracer (³H-CH₄) incubations, CH₄ concentration profiling, and particulate methane monooxygenase (pmoA) gene quantification, we sampled vertical and horizontal transects and near-bottom waters via the HOV Alvin. CH₄ oxidation was active not only within seep plumes but also in off-seep regions, with the highest rate (454 nanomoles per liter per day) observed within a CH₄-rich bubble plume. pmoA gene abundances remained relatively stable across both seep and off-seep waters, suggesting a persistent CH₄-oxidizing potential. These findings support an expanded "methanosphere," a CH₄-influenced microbial zone shaped by physical transport and environmental gradients. This dataset is part of a PhD thesis: Klonicki-Ference, Emily F. "Microbial Regulation of Methane and Redox Dynamics in the Water Column: From a Proterozoic Ocean Analog to Modern Marine Seeps." PhD diss., University of California, Los Angeles, 2025. BCO-DMO info@bco-dmo.org https://osprey.bco-dmo.org/dataset/986866 information web browser Background Information Background information from the source information pointOfContact earth science atmosphere ocean biosphere biology environment theme BCO-DMO project time latitude longitude theme CF The data may be used and redistributed for free but is not intended for legal use, since it may contain inaccuracies. Neither the data Contributor, ERD, NOAA, nor the United States Government, nor any of their employees or contractors, makes any warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, or assumes any legal liability for the accuracy, completeness, or usefulness, of this information. BCO-DMO largerWorkCitation project eng geoscientificInformation 1 -118.6488 -117.7765 32.8339 33.8003 seconds 2023-07-17T16:50:00Z 2023-07-26T15:45:00Z [Water column methane, methane oxidation, and pmoA gene copies] - Water column methane, methane oxidation, and pmoA gene copies above southern California methane seeps determined from samples collected on R/V Atlantis cruise AT50-12 in July 2023 (Collaborative Research: Redefining the footprint of deep ocean methane seepage for benthic ecosystems) 2026-04-08 creation BCO-DMO info@bco-dmo.org https://osprey.bco-dmo.org/dataset/986866 information web browser Background Information Background information from the source information originator Marine methane (CH₄) seeps are dynamic biogeochemical systems that modulate carbon cycling and support high-biomass communities through microbial methane (CH₄) oxidation. While most CH₄ is consumed anaerobically in sediments, a fraction enters the water column, where aerobic methanotrophs form a biological filter limiting CH₄ flux to the atmosphere. However, the extent to which this microbial activity and CH₄ influence extend beyond visibly active seep zones remains poorly constrained, with implications for deep-sea food webs, biogeochemical gradients, and carbon cycling. We investigated CH₄ dynamics and methanotroph distribution across three seep sites on the Southern California margin (Del Mar, Santa Monica (800 meters) Mound, Lasuen Knoll; ~400–1200 meters depth). Using radiotracer (³H-CH₄) incubations, CH₄ concentration profiling, and particulate methane monooxygenase (pmoA) gene quantification, we sampled vertical and horizontal transects and near-bottom waters via the HOV Alvin. CH₄ oxidation was active not only within seep plumes but also in off-seep regions, with the highest rate (454 nanomoles per liter per day) observed within a CH₄-rich bubble plume. pmoA gene abundances remained relatively stable across both seep and off-seep waters, suggesting a persistent CH₄-oxidizing potential. These findings support an expanded "methanosphere," a CH₄-influenced microbial zone shaped by physical transport and environmental gradients. This dataset is part of a PhD thesis: Klonicki-Ference, Emily F. "Microbial Regulation of Methane and Redox Dynamics in the Water Column: From a Proterozoic Ocean Analog to Modern Marine Seeps." PhD diss., University of California, Los Angeles, 2025. ERDDAP tabledap 1 -118.6488 -117.7765 32.8339 33.8003 seconds 2023-07-17T16:50:00Z 2023-07-26T15:45:00Z tight ERDDAPtabledapDatasetQueryAndAccess https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_986866_v1 ERDDAP:tabledap ERDDAP-tabledap ERDDAP's tabledap service (a flavor of OPeNDAP) for tabular (sequence) data. Add different extensions (e.g., .html, .graph, .das, .dds) to the base URL for different purposes. download [Water column methane, methane oxidation, and pmoA gene copies] - Water column methane, methane oxidation, and pmoA gene copies above southern California methane seeps determined from samples collected on R/V Atlantis cruise AT50-12 in July 2023 (Collaborative Research: Redefining the footprint of deep ocean methane seepage for benthic ecosystems) 2026-04-08 creation BCO-DMO info@bco-dmo.org https://osprey.bco-dmo.org/dataset/986866 information web browser Background Information Background information from the source information originator Marine methane (CH₄) seeps are dynamic biogeochemical systems that modulate carbon cycling and support high-biomass communities through microbial methane (CH₄) oxidation. While most CH₄ is consumed anaerobically in sediments, a fraction enters the water column, where aerobic methanotrophs form a biological filter limiting CH₄ flux to the atmosphere. However, the extent to which this microbial activity and CH₄ influence extend beyond visibly active seep zones remains poorly constrained, with implications for deep-sea food webs, biogeochemical gradients, and carbon cycling. We investigated CH₄ dynamics and methanotroph distribution across three seep sites on the Southern California margin (Del Mar, Santa Monica (800 meters) Mound, Lasuen Knoll; ~400–1200 meters depth). Using radiotracer (³H-CH₄) incubations, CH₄ concentration profiling, and particulate methane monooxygenase (pmoA) gene quantification, we sampled vertical and horizontal transects and near-bottom waters via the HOV Alvin. CH₄ oxidation was active not only within seep plumes but also in off-seep regions, with the highest rate (454 nanomoles per liter per day) observed within a CH₄-rich bubble plume. pmoA gene abundances remained relatively stable across both seep and off-seep waters, suggesting a persistent CH₄-oxidizing potential. These findings support an expanded "methanosphere," a CH₄-influenced microbial zone shaped by physical transport and environmental gradients. This dataset is part of a PhD thesis: Klonicki-Ference, Emily F. "Microbial Regulation of Methane and Redox Dynamics in the Water Column: From a Proterozoic Ocean Analog to Modern Marine Seeps." PhD diss., University of California, Los Angeles, 2025. OPeNDAP 1 -118.6488 -117.7765 32.8339 33.8003 seconds 2023-07-17T16:50:00Z 2023-07-26T15:45:00Z tight OPeNDAPDatasetQueryAndAccess https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_986866_v1 OPeNDAP:OPeNDAP OPeNDAP An OPeNDAP service for tabular (sequence) data. Add different extensions (e.g., .html, .das, .dds) to the base URL for different purposes. download physicalMeasurement Date_UTC String Date_utc CTD_Start_Time_or_Alvin_Niskin_Closure_UTC String Ctd_start_time_or_alvin_niskin_closure_utc time double Iso_datetime_utc Site_Name String Site_name CTD_or_Alvin_Sample_Number String Ctd_or_alvin_sample_number Waypoint int Waypoint Water_Depth int Water_depth Methane float Methane Methane_oxidation_Replicate_1 float Methane_oxidation_replicate_1 Methane_oxidation_Replicate_2 float Methane_oxidation_replicate_2 Methane_oxidation_Replicate_3 float Methane_oxidation_replicate_3 pmoA_gene_copy_number float Pmoa_gene_copy_number Adam Shepherd BCO-DMO 508-289-2772 266 Woods Hole Rd. MS#36 Woods Hole MA 02543 USA erddap@bco-dmo.org distributor OPeNDAP DAP/2.0 https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_986866_v1.html order Data Subset Form ERDDAP's version of the OPeNDAP .html web page for this dataset. Specify a subset of the dataset and download the data via OPeNDAP or in many different file types. download https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_986866_v1.graph order Make-A-Graph Form ERDDAP's Make-A-Graph .html web page for this dataset. Create an image with a map or graph of a subset of the data. mapDigital This record was created from dataset metadata by ERDDAP Version 2.22