Attributes { s { inoculum { String bcodmo_name "incubation time"; String description "Fresh: incubation performed on shipboard with freshly collected samples; Stored: incubation completed within one year of collection."; String long_name "Inoculum"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/AZDRZZ01/"; String units "unitless"; } experiment_num { String bcodmo_name "exp_id"; String description "PI issued experiment ID number"; String long_name "Experiment Num"; String units "unitless"; } latitude { String _CoordinateAxisType "Lat"; Float64 _FillValue NaN; Float64 actual_range 47.95, 47.95; String axis "Y"; String bcodmo_name "latitude"; Float64 colorBarMaximum 90.0; Float64 colorBarMinimum -90.0; String description "Latitude"; String ioos_category "Location"; String long_name "Latitude"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/LATX/"; String standard_name "latitude"; String units "degrees_north"; } longitude { String _CoordinateAxisType "Lon"; Float64 _FillValue NaN; Float64 actual_range -129.1, -129.1; String axis "X"; String bcodmo_name "longitude"; Float64 colorBarMaximum 180.0; Float64 colorBarMinimum -180.0; String description "Longitude"; String ioos_category "Location"; String long_name "Longitude"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/LONX/"; String standard_name "longitude"; String units "degrees_east"; } sulfide { Float32 _FillValue NaN; Float32 actual_range 1.0e-9, 0.001; String bcodmo_name "sulfide"; String description "Independently varied concentration of sulfide"; String long_name "Sulfide"; String units "molar (M)"; } DOC { Float32 _FillValue NaN; Float32 actual_range 0.0, 50.0; String bcodmo_name "DOC"; String description "Independently varied dissolved oxygen concentration"; String long_name "DOC"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/CORGZZZX/"; String units "micromoles (uM)"; } sulfate { Float32 _FillValue NaN; Float32 actual_range 1.0e-5, 14.0; String bcodmo_name "SO4"; String description "Independently varied concentration of sulfate"; String long_name "Sulfate"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/SPHTMAXX/"; String units "millimoles (mM)"; } pH { Byte _FillValue 127; Byte actual_range 4, 6; String bcodmo_name "pH"; Float64 colorBarMaximum 9.0; Float64 colorBarMinimum 7.0; String description "pH of media added to incubations; Incubations were carried out at either pH 4 or 6; 4: simulates the pH of end-member Grotto vent fluid and the average calculated pH of mixed fluids in highly reduced zones within flange (Tivey 2004). 6: represents the calculated pH in fluid mixing zones (Tivey 2004)."; String long_name "Sea Water Ph Reported On Total Scale"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/PHXXZZXX/"; String units "pH"; } temperature { Byte _FillValue 127; Byte actual_range 4, 90; String bcodmo_name "temperature"; String description "Temperatures at which samples were incubated anaerobically for 1, 3, or 7 days. 4 C: ambient seawater; 50 C: thermophilic; 90 C: hyperthermophilic."; String long_name "Temperature"; String units "celsius (C)"; } SRrate_3day { Float32 _FillValue NaN; Float32 actual_range 0.0, 1695.552; String bcodmo_name "SO4"; String description "Sulfate reduction rate after 3 day incubation"; String long_name "SRrate 3day"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/SPHTMAXX/"; String units "nmol/gday"; } SRrate_3day_replicates { Byte _FillValue 127; Byte actual_range 3, 3; String bcodmo_name "num_reps"; String description "Number of replicates used for 3 day incubation"; String long_name "SRrate 3day Replicates"; String units "count"; } SRrate_7day { Float32 _FillValue NaN; Float32 actual_range 0.0, 1678.113; String bcodmo_name "SO4"; String description "Sulfate reduction rate after 7 day incubation"; String long_name "SRrate 7day"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/SPHTMAXX/"; String units "nmol/gday"; } SRrate_7day_replicates { Byte _FillValue 127; Byte actual_range 0, 3; String bcodmo_name "num_reps"; String description "Number of replicates used for 7 day incubation"; String long_name "SRrate 7day Replicates"; String units "count"; } SRrate_inhibited { Float32 _FillValue NaN; Float32 actual_range 0.0, 9.19; String bcodmo_name "SO4"; String description "Sulfate reduction rate molybdate inhibited controls"; String long_name "SRrate Inhibited"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/SPHTMAXX/"; String units "nmol/gday"; } SRrate_inhibited_replicates { Byte _FillValue 127; Byte actual_range 2, 2; String bcodmo_name "num_reps"; String description "Number of replicates used for molybdate inhibited controls"; String long_name "SRrate Inhibited Replicates"; String units "count"; } } NC_GLOBAL { String access_formats ".htmlTable,.csv,.json,.mat,.nc,.tsv,.esriCsv,.geoJson"; String acquisition_description "Tables and Figures referenced in the acquisition description are found in the paper Frank et al., 2015 Once on board ship,\\u00a0tubeworms\\u00a0and other macrofauna were removed from the samples and the large pieces were broken into more manageable fragments (~10-20 cm3) with a flame-sterilized chisel and sledgehammer, with the user wearing sterile nitrile gloves. Samples were quickly transferred to 0.2 um- filtered anaerobic (nitrogen-sparged) seawater. Samples were further broken down into smaller sizes while in anaerobic water, and subsamples from the interior of the fragments were immediately transferred to gastight jars (Freund Container Inc.) filled with sterile anaerobic seawater containing 2 mM sodium sulfide at pH 6, and stored at 4 degrees celsius for incubations and analyses. The sterile sulfidic seawater in the gastight jars\\u00a0were\\u00a0refreshed periodically during storage at 4 degrees celsius. The majority of the rate experiments (80%) were set up immediately on the ship using freshly collected samples. In parallel, subsamples (~1 cm3) from each flange were preserved aboard ship in glutaraldehyde (2.5% in phosphate buffered saline, PBS, pH 7.0), then prepared for electron microscopy via ethanol dehydration and critical point drying before being sputtered with a thin layer of gold-palladium to improve image resolution. Samples were imaged with a Zeiss model EVO Scanning Electron Microscope (SEM).\\u00a0 Prior to incubation, each flange subsample was pulverized by hand for about one hour to minimize fine-scale geological and microbial heterogeneity and facilitate more accurate experimental replication (akin to slurry experiments in sediments; Fossing & J\\u00f8rgensen 1989; Weber & J\\u00f8rgensen 2002; J\\u00f8rgensen\\u00a0et al.\\u00a01992). Specifically, each subsample was pulverized with a flame-sterilized sledgehammer in sterile seawater actively bubbled with nitrogen within an anaerobic chamber. For each independent treatment, aliquots of 7.5 mL flange slurry (approx. 29 g wet weight and 20 g dry weight) were transferred into Balch tubes in an anaerobic chamber, and supplemented with 15 mL of sterile artificial seawater media designed to mimic the geochemical conditions within a hydrothermal flange (400 mM NaCl, 25 mM KCl, 30 mM CaCl2, 2.3 mM NaHCO3, 14 mM NaSO42-, 1 mM H2S, and 50 uM dissolved organic carbon - consisting of equimolar proportions 10 uM of pyruvate, citrate, formate, acetate, lactate) under a pure nitrogen headspace.\\u00a0 Concentrations of sulfide, sulfate and dissolved organic carbon (DOC) were varied independently to investigate concentration dependent effects on the rates of SR. The range of experimental conditions tested was determined from previously published concentration profiles of aqueous species modeled as functions of temperature and position within the Grotto vent structure (Tivey, 2004). Concentrations were varied by orders of magnitude within the modeled ranges to simulate conditions representative of different mixing regimes between seawater and vent fluid (Table 1). The range of DOC (which we approximate as a mix of pyruvate, citrate, formate, acetate, lactate \\u2013 most of which have been identified to varying degrees within vent fluid and are known carbon sources for heterotrophic SR in culture) concentrations tested were based on the average DOC concentrations measured within diffuse fluids at the Main Endeavor Field (Lang\\u00a0et al., 2006; Lang\\u00a0et al.,\\u00a02010). Hydrogen sulfide was present as H2S (pKa\\u00a0in seawater of 6.60) across all the conditions tested (Amend & Shock, 2001). Incubations were carried out at pH 4 (to simulate the pH of end-member Grotto vent fluid and the average calculated pH of\\u00a0mixed fluids in highly reduced zones within the flange; Tivey 2004) as well as pH 6 (representative of the calculated pH in fluid mixing zones; Tivey 2004). All the results are presented and discussed in the context of the initial measured media conditions.\\u00a0 Sufficient\\u00a035SO42-\\u00a0was added to achieve 15 uCi of activity. Samples were incubated anaerobically for 1, 3 or 7 days at ambient seawater (4 degrees celsius), thermophilic (50 degrees celsius) and hyperthermophilic (90 degrees celsius) temperatures. The range of temperatures considered was representative of different thermal regimes associated with the surface, outer layer and middle regions of hydrothermal chimneys (Tivey 2004; Kormas\\u00a0et al.\\u00a02006; Schrenk\\u00a0et al. 2003). Negative controls consisted of samples amended with 28 mM molybdate to inhibit SR (Newport & Nedwell, 1988; Saleh\\u00a0et al., 1964). Three biological replicates were run for each treatment, and two biological replicates for each control.\\u00a0 Upon completion, reactions were quenched with the injection of 5 mL 25% zinc acetate, at pH 8 (i.e. 20-fold excess Zn), and all samples were frozen at -20 degrees celsius for further analysis. 80% of incubations were performed shipboard with freshly collected samples and the remaining 20% of incubations were completed within one year of collection.\\u00a0 To determine SR rates, samples were thawed and the supernatant was removed and filtered through a 0.2 um syringe filter. The homogenized flange that remained in the tube was washed three times with deionized water to remove any remaining sulfate. One gram (wet weight) of flange material was added to 10 mL of a 1:1 ethanol to water solution in the chromium distillation apparatus, and then degassed with nitrogen for 15 minutes to drive the environment anoxic. Hydrogen sulfide gas was evolved after the anaerobic addition of 8 mL of 12 N HCl and 10 mL of 1 M reduced chromium chloride, followed by 3 hours of heating. The resulting hydrogen sulfide gas was carried via nitrogen gas through a condenser to remove\\u00a0HCl,\\u00a0and was then trapped as zinc sulfide in a 25% zinc acetate solution. To moderate potential artifacts of hot distillation methods including elevated rates in control samples, experiments were analyzed in triplicate, on different days and with different glassware to minimize cross-contamination, and any activity observed in \\u201ccontrol\\u201d samples was deleted from the treatments. The radioactivity of the resulting sulfide (Zn35S) and the remaining sulfate from the supernatant (35SO42-)\\u00a0were\\u00a0measured via liquid scintillation counter in Ultima Gold scintillation cocktail (ThermoFisher Inc., Waltham, MA).\\u00a0 Once on board ship,\\u00a0tubeworms\\u00a0and other macrofauna were removed from the samples and the large pieces were broken into more manageable fragments (~10-20 cm3) with a flame-sterilized chisel and sledgehammer, with the user wearing sterile nitrile gloves. Samples were quickly transferred to 0.2 um- filtered anaerobic (nitrogen-sparged) seawater. Samples were further broken down into smaller sizes while in anaerobic water, and subsamples from the interior of the fragments were immediately transferred to gastight jars (Freund Container Inc.) filled with sterile anaerobic seawater containing 2 mM sodium sulfide at pH 6, and stored at 4 degrees celsius for incubations and analyses. The sterile sulfidic seawater in the gastight jars\\u00a0were\\u00a0refreshed periodically during storage at 4 degrees celsius. The majority of the rate experiments (80%) were set up immediately on the ship using freshly collected samples. In parallel, subsamples (~1 cm3) from each flange were preserved aboard ship in glutaraldehyde (2.5% in phosphate buffered saline, PBS, pH 7.0), then prepared for electron microscopy via ethanol dehydration and critical point drying before being sputtered with a thin layer of gold-palladium to improve image resolution. Samples were imaged with a Zeiss model EVO Scanning Electron Microscope (SEM).\\u00a0 Prior to incubation, each flange subsample was pulverized by hand for about one hour to minimize fine-scale geological and microbial heterogeneity and facilitate more accurate experimental replication (akin to slurry experiments in sediments; Fossing & J\\u00f8rgensen 1989; Weber & J\\u00f8rgensen 2002; J\\u00f8rgensen et al. 1992). Specifically, each subsample was pulverized with a flame-sterilized sledgehammer in sterile seawater actively bubbled with nitrogen within an anaerobic chamber. For each independent treatment, aliquots of 7.5 mL flange slurry (approx. 29 g wet weight and 20 g dry weight) were transferred into Balch tubes in an anaerobic chamber, and supplemented with 15 mL of sterile artificial seawater media designed to mimic the geochemical conditions within a hydrothermal flange (400 mM NaCl, 25 mM KCl, 30 mM CaCl2, 2.3 mM NaHCO3, 14 mM NaSO42-, 1 mM H2S, and 50 uM dissolved organic carbon - consisting of equimolar proportions 10 uM of pyruvate, citrate, formate, acetate, lactate) under a pure nitrogen headspace.\\u00a0 Concentrations of sulfide, sulfate and dissolved organic carbon (DOC) were varied independently to investigate concentration dependent effects on the rates of SR. The range of experimental conditions tested was determined from previously published concentration profiles of aqueous species modeled as functions of temperature and position within the Grotto vent structure (Tivey, 2004). Concentrations were varied by orders of magnitude within the modeled ranges to simulate conditions representative of different mixing regimes between seawater and vent fluid (Table 1). The range of DOC (which we approximate as a mix of pyruvate, citrate, formate, acetate, lactate \\u2013 most of which have been identified to varying degrees within vent fluid and are known carbon sources for heterotrophic SR in culture) concentrations tested were based on the average DOC concentrations measured within diffuse fluids at the Main Endeavor Field (Lang et al., 2006; Lang et al., 2010). Hydrogen sulfide was present as H2S (pKa in seawater of 6.60) across all the conditions tested (Amend & Shock, 2001). Incubations were carried out at pH 4 (to simulate the pH of end-member Grotto vent fluid and the average calculated pH of mixed fluids in highly reduced zones within the flange; Tivey 2004) as well as pH 6 (representative of the calculated pH in fluid mixing zones; Tivey 2004). All the results are presented and discussed in the context of the initial measured media conditions.\\u00a0 Sufficient 35SO42- was added to achieve 15 uCi of activity. Samples were incubated anaerobically for 1, 3 or 7 days at ambient seawater (4 degrees celsius), thermophilic (50 degrees celsius) and hyperthermophilic (90 degrees celsius) temperatures. The range of temperatures considered was representative of different thermal regimes associated with the surface, outer layer and middle regions of hydrothermal chimneys (Tivey 2004; Kormas et al. 2006; Schrenk et al. 2003). Negative controls consisted of samples amended with 28 mM molybdate to inhibit SR (Newport & Nedwell, 1988; Saleh et al., 1964). Three biological replicates were run for each treatment, and two biological replicates for each control.\\u00a0 Upon completion, reactions were quenched with the injection of 5 mL 25% zinc acetate, at pH 8 (i.e. 20-fold excess Zn), and all samples were frozen at -20 degrees celsius for further analysis. 80% of incubations were performed shipboard with freshly collected samples and the remaining 20% of incubations were completed within one year of collection.\\u00a0 To determine SR rates, samples were thawed and the supernatant was removed and filtered through a 0.2 um syringe filter. The homogenized flange that remained in the tube was washed three times with deionized water to remove any remaining sulfate. One gram (wet weight) of flange material was added to 10 mL of a 1:1 ethanol to water solution in the chromium distillation apparatus, and then degassed with nitrogen for 15 minutes to drive the environment anoxic. Hydrogen sulfide gas was evolved after the anaerobic addition of 8 mL of 12 N HCl and 10 mL of 1 M reduced chromium chloride, followed by 3 hours of heating. The resulting hydrogen sulfide gas was carried via nitrogen gas through a condenser to remove\\u00a0HCl,\\u00a0and was then trapped as zinc sulfide in a 25% zinc acetate solution. To moderate potential artifacts of hot distillation methods including elevated rates in control samples, experiments were analyzed in triplicate, on different days and with different glassware to minimize cross-contamination, and any activity observed in \\u201ccontrol\\u201d samples was deleted from the treatments. The radioactivity of the resulting sulfide (Zn35S) and the remaining sulfate from the supernatant (35SO42-)\\u00a0were\\u00a0measured via liquid scintillation counter in Ultima Gold scintillation cocktail (ThermoFisher Inc., Waltham, MA).\\u00a0"; String awards_0_award_nid "554913"; String awards_0_award_number "OCE-1061934"; String awards_0_data_url "http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1061934"; String awards_0_funder_name "NSF Division of Ocean Sciences"; String awards_0_funding_acronym "NSF OCE"; String awards_0_funding_source_nid "355"; String awards_0_program_manager "David L. Garrison"; String awards_0_program_manager_nid "50534"; String awards_1_award_nid "626305"; String awards_1_award_number "OCE-0838107"; String awards_1_data_url "http://www.nsf.gov/awardsearch/showAward?AWD_ID=0838107"; String awards_1_funder_name "NSF Division of Ocean Sciences"; String awards_1_funding_acronym "NSF OCE"; String awards_1_funding_source_nid "355"; String awards_1_program_manager "Kandace S Binkley"; String awards_1_program_manager_nid "51512"; String awards_2_award_nid "626308"; String awards_2_award_number "NNX09AB78G"; String awards_2_funder_name "NASA Astrobiology Science & Technology for Exploring Planets"; String awards_2_funding_acronym "NASA-ASTEP"; String awards_2_funding_source_nid "626307"; String awards_3_award_nid "626309"; String awards_3_award_number "NNX07AV51G"; String awards_3_funder_name "NASA Astrobiology Science & Technology for Exploring Planets"; String awards_3_funding_acronym "NASA-ASTEP"; String awards_3_funding_source_nid "626307"; String cdm_data_type "Other"; String comment "Sulfate Reduction Rates P. Girguis, PI Version 13 October 2016"; String Conventions "COARDS, CF-1.6, ACDD-1.3"; String creator_email "info@bco-dmo.org"; String creator_name "BCO-DMO"; String creator_type "institution"; String creator_url "https://www.bco-dmo.org/"; String data_source "extract_data_as_tsv version 2.3 19 Dec 2019"; String date_created "2016-10-13T21:40:27Z"; String date_modified "2019-04-22T18:17:30Z"; String defaultDataQuery "&time<now"; String doi "10.1575/1912/bco-dmo.661557.1"; Float64 Easternmost_Easting -129.1; Float64 geospatial_lat_max 47.95; Float64 geospatial_lat_min 47.95; String geospatial_lat_units "degrees_north"; Float64 geospatial_lon_max -129.1; Float64 geospatial_lon_min -129.1; String geospatial_lon_units "degrees_east"; String history "2024-03-29T06:29:40Z (local files) 2024-03-29T06:29:40Z https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_661557.das"; String infoUrl "https://www.bco-dmo.org/dataset/661557"; String institution "BCO-DMO"; String instruments_0_acronym "in-situ incubator"; String instruments_0_dataset_instrument_description "Used aboard ship and in lab"; String instruments_0_dataset_instrument_nid "661748"; String instruments_0_description "A device on shipboard or in the laboratory that holds water samples under controlled conditions of temperature and possibly illumination."; String instruments_0_instrument_external_identifier "https://vocab.nerc.ac.uk/collection/L05/current/82/"; String instruments_0_instrument_name "In-situ incubator"; String instruments_0_instrument_nid "494"; String instruments_0_supplied_name "Incubator"; String instruments_1_acronym "LSC"; String instruments_1_dataset_instrument_description "Used to quantify activity"; String instruments_1_dataset_instrument_nid "661807"; String instruments_1_description "Liquid scintillation counting is an analytical technique which is defined by the incorporation of the radiolabeled analyte into uniform distribution with a liquid chemical medium capable of converting the kinetic energy of nuclear emissions into light energy. Although the liquid scintillation counter is a sophisticated laboratory counting system used the quantify the activity of particulate emitting (ß and a) radioactive samples, it can also detect the auger electrons emitted from 51Cr and 125I samples."; String instruments_1_instrument_external_identifier "https://vocab.nerc.ac.uk/collection/L05/current/LAB21/"; String instruments_1_instrument_name "Liquid Scintillation Counter"; String instruments_1_instrument_nid "624"; String instruments_1_supplied_name "Liquid scintillation counter"; String instruments_2_acronym "pH Sensor"; String instruments_2_dataset_instrument_description "pH sensor"; String instruments_2_dataset_instrument_nid "661637"; String instruments_2_description "General term for an instrument that measures the pH or how acidic or basic a solution is."; String instruments_2_instrument_name "pH Sensor"; String instruments_2_instrument_nid "674"; String instruments_2_supplied_name "pH sensor"; String instruments_3_acronym "Dissolved Oxygen Sensor"; String instruments_3_dataset_instrument_description "DOC was measured"; String instruments_3_dataset_instrument_nid "661638"; String instruments_3_description "An electronic device that measures the proportion of oxygen (O2) in the gas or liquid being analyzed"; String instruments_3_instrument_name "Dissolved Oxygen Sensor"; String instruments_3_instrument_nid "705"; String instruments_3_supplied_name "DO sensor"; String instruments_4_dataset_instrument_description "Tubeworm and macrofauna subsamples were imaged."; String instruments_4_dataset_instrument_nid "661635"; String instruments_4_description "Instruments that generate enlarged images of samples using the phenomena of reflection and absorption of electrons behaving as waves."; String instruments_4_instrument_external_identifier "https://vocab.nerc.ac.uk/collection/L05/current/LAB07/"; String instruments_4_instrument_name "Microscope-Electron"; String instruments_4_instrument_nid "709"; String instruments_4_supplied_name "Zeiss model EVO Scanning Electron Microscope"; String keywords "3day, 7day, bco, bco-dmo, biological, chemical, chemistry, commerce, data, dataset, department, dmo, doc, earth, Earth Science > Oceans > Ocean Chemistry > pH, erddap, experiment, experiment_num, inhibited, inoculum, latitude, longitude, management, num, ocean, oceanography, oceans, office, preliminary, replicates, reported, scale, science, sea, sea_water_ph_reported_on_total_scale, seawater, srrate, SRrate_3day, SRrate_3day_replicates, SRrate_7day, SRrate_7day_replicates, SRrate_inhibited, SRrate_inhibited_replicates, sulfate, sulfide, temperature, total, water"; String keywords_vocabulary "GCMD Science Keywords"; String license "https://www.bco-dmo.org/dataset/661557/license"; String metadata_source "https://www.bco-dmo.org/api/dataset/661557"; Float64 Northernmost_Northing 47.95; String param_mapping "{'661557': {'lat': 'master - latitude', 'lon': 'master - longitude'}}"; String parameter_source "https://www.bco-dmo.org/mapserver/dataset/661557/parameters"; String people_0_affiliation "Harvard University"; String people_0_person_name "Peter Girguis"; String people_0_person_nid "544586"; String people_0_role "Principal Investigator"; String people_0_role_type "originator"; String people_1_affiliation "University of Hawaii at Manoa"; String people_1_affiliation_acronym "SOEST"; String people_1_person_name "Kiana Frank"; String people_1_person_nid "626318"; String people_1_role "Contact"; String people_1_role_type "related"; String people_2_affiliation "Woods Hole Oceanographic Institution"; String people_2_affiliation_acronym "WHOI BCO-DMO"; String people_2_person_name "Hannah Ake"; String people_2_person_nid "650173"; String people_2_role "BCO-DMO Data Manager"; String people_2_role_type "related"; String project "North Pond Microbes,Middle Valley Vents"; String projects_0_acronym "North Pond Microbes"; String projects_0_description "Description from NSF award abstract: Current estimates suggest that the volume of ocean crust capable of sustaining life is comparable in magnitude to that of the oceans. To date, there is little understanding of the composition or functional capacity of microbial communities in the sub-seafloor, or their influence on the chemistry of the oceans and subsequent consequences for global biogeochemical cycles. This project focuses on understanding the relationship between microbial communities and fluid chemistry in young crustal fluids that are responsible for the transport of energy, nutrients, and organisms in the crust. Specifically, the PIs will couple microbial activity measurements, including autotrophic carbon, nitrogen and sulfur metabolisms as well as mineral oxide reduction, with quantitative assessments of functional gene expression and geochemical transformations in basement fluids. Through a comprehensive suite of in situ and shipboard analyses, this research will yield cross-disciplinary advances in our understanding of the microbial ecology and geochemistry of the sub-seafloor biosphere. The focus of the effort is at North Pond, an isolated sediment pond located on ridge flank oceanic crust 7-8 million years old on the western side of the Mid-Atlantic Ridge. North Pond is currently the target for drilling on IODP expedition 336, during which it will be instrumented with three sub-seafloor basement observatories. The project will leverage this opportunity for targeted and distinct sampling at North Pond on two German-US research cruises to accomplish three main objectives: 1. to determine if different basement fluid horizons across North Pond host distinct microbial communities and chemical milieus and the degree to which they change over a two-year post-drilling period. 2. to quantify the extent of autotrophic metabolism via microbially-mediated transformations in carbon, nitrogen, and sulfur species in basement fluids at North Pond. 3. to determine the extent of suspended particulate mineral oxides in basement fluids at North Pond and to characterize their role as oxidants for fluid-hosted microbial communities. Specific outcomes include quantitative assessments of microbial activity and gene expression as well as geochemical transformations. The program builds on the integrative research goals for North Pond and will provide important data for guiding the development of that and future deep biosphere research programs. Results will increase understanding of microbial life and chemistry in young oceanic crust as well as provide new insights into controls on the distribution and activity of marine microbial communities throughout the worlds oceans. There are no data about microbial communities in ubiquitous cold, oceanic crust, the emphasis of the proposed work. This is an interdisciplinary project at the interface of microbial ecology, chemistry, and deep-sea oceanography with direct links to international and national research and educational organizations."; String projects_0_end_date "2015-05"; String projects_0_geolocation "North Pond, mid-Atlantic Ridge"; String projects_0_name "Collaborative Research: Characterization of Microbial Transformations in Basement Fluids, from Genes to Geochemical Cycling"; String projects_0_project_nid "554914"; String projects_0_start_date "2011-06"; String projects_1_acronym "Middle Valley Vents"; String projects_1_description "This project characterizes rates of microbially mediated sulfate reduction from three distinct hydrothermal vents in the Middle Valley vent field along the Juan de Fuca Ridge, as well as assessments of bacterial and archaeal diversity, estimates of total biomass and the abundance of functional genes related to sulfate reduction, and in situ geochemistry. Maximum rates of sulfate reduction occurred at 90°C in all three deposits. Pyrosequencing and functional gene abundance data reveal differences in both biomass and community composition among sites, including differences in the abundance of known sulfate reducing bacteria. The abundance of sequences for Thermodesulfovibro-like organisms and higher sulfate reduction rates at elevated temperatures, suggests that Thermodesulfovibro-like organisms may play a role in sulfate reduction in warmer environments. The rates of sulfate reduction observed suggest that - within anaerobic niches of hydrothermal deposits - heterotrophic sulfate reduction may be quite common and might contribute substantially to secondary productivity, underscoring the potential role of this process in both sulfur and carbon cycling at vents. This project was funded, in part, by a C-DEBI Graduate Student Fellowship."; String projects_1_geolocation "Middle Valley vent field along the Juan de Fuca Ridge"; String projects_1_name "Characterizing the distribution and rates of microbial sulfate reduction at Middle Valley hydrothermal vents"; String projects_1_project_nid "626603"; String publisher_name "Biological and Chemical Oceanographic Data Management Office (BCO-DMO)"; String publisher_type "institution"; String sourceUrl "(local files)"; Float64 Southernmost_Northing 47.95; String standard_name_vocabulary "CF Standard Name Table v55"; String subsetVariables "latitude,longitude,SRrate_3day_replicates,SRrate_inhibited_replicates"; String summary "Sulfate reduction rates at Main Endeavor grotto chimney from samples collected on RV Atlantis (AT18-08) during Jason II dives in the Juan de Fuca Ridge from July to August 2011"; String title "Sulfate reduction rates at Main Endeavor grotto chimney from samples collected on RV Atlantis (AT18-08) during Jason II dives in the Juan de Fuca Ridge from July to August 2011"; String version "1"; Float64 Westernmost_Easting -129.1; String xml_source "osprey2erddap.update_xml() v1.3"; } }