USAP-DC

{"dp_type": "Dataset", "free_text": "Nitrogen"}

[{"awards": "0739512 Walker, Sally; 1745064 Perez-Huerta, Alberto; 1745057 Walker, Sally; 1745080 Gillikin, David", "bounds_geometry": null, "date_created": "Mon, 05 Feb 2024 00:00:00 GMT", "description": "Adamussium colbecki is a large thin-shelled scallop common in Antarctic waters and well represented in the fossil record. Shell nitrogen isotopes in carbonate bound organic matter (d15NCBOM) have the potential to record sea ice state over time. Recent studies illustrated that d15NCBOM values provide a similar proxy as soft tissue d15N values which are in turn are predicably related to food d15N values (Gillikin et al., 2017, GCA, 200, 55\u201366, doi: 10.1016/j.gca.2016.12.008). Sea-ice organic N should have higher d15N values compared to open water organics due to nitrate draw down in the ice (Fripiat et al., 2014, Global Biogeochem. Cycles, 28, 115\u2013130, doi:10.1002/2013GB004729). To test this hypothesis we analyzed A. colbecki shells from Explorers Cove and Bay of Sails, western McMurdo Sound, Antarctica. These sites have different sea ice states: persistent (multiannual) sea ice at Explorers Cove and annual sea ice (that melts out every year) at Bay of Sails. Six adults shells collected at these sites in 2008 (3 from each site) and two juveniles collected in 2016 from Explorers Cove were be serially sampled for d15NCBOM values from the growing shell margin to the umbo. d15NCBOM values from Explorers Cove with persistent sea ice cover were consistently higher (+10 \u00b1 0.7 \u2030) than those from Bay of Sails where the sea ice melts out every year (+8 \u00b1 0.5 \u2030; t-test p\u003c0.0001). d15NCBOM data from Mid- to Late Holocene shells that grew in these locations will also be presented. We posit that nitrogen isotopes in A. colbecki shells have a high potential to record sea ice cover.", "east": null, "geometry": null, "keywords": "Adamussium Colbecki; Antarctica; Biota; Carbon Isotopes; Explorers Cove; Nitrogen Isotopes; Oxygen Isotope; Scallop", "locations": "Explorers Cove; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "persons": "Gillikin, David; Puhalski, Emma; Camarra, Steve; Cronin, Kelly; Verheyden, Anouk; Walker, Sally", "project_titles": "Collaborative Research: Linking Modern Benthic Communities and Taphonomic Processes to the Stratigraphic Record of Antarctic Cores; Collaborative research: The Antarctic Scallop as Key to Paleoenvironments and Sea Ice Conditions: Understanding the Modern to Predict the Past", "projects": [{"proj_uid": "p0000203", "repository": "USAP-DC", "title": "Collaborative Research: Linking Modern Benthic Communities and Taphonomic Processes to the Stratigraphic Record of Antarctic Cores"}, {"proj_uid": "p0010238", "repository": "USAP-DC", "title": "Collaborative research: The Antarctic Scallop as Key to Paleoenvironments and Sea Ice Conditions: Understanding the Modern to Predict the Past"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Nitrogen, carbon, and oxygen isotopes in the shell of the Antarctic scallop Adamussium colbecki as a proxy for sea ice cover in Antarctica.", "uid": "601764", "west": null}, {"awards": "1443386 Emslie, Steven; 1443424 McMahon, Kelton; 1443585 Polito, Michael; 1826712 McMahon, Kelton", "bounds_geometry": ["POLYGON((-180 -61.59,-168.969 -61.59,-157.938 -61.59,-146.90699999999998 -61.59,-135.876 -61.59,-124.845 -61.59,-113.814 -61.59,-102.783 -61.59,-91.752 -61.59,-80.72099999999999 -61.59,-69.69 -61.59,-69.69 -63.195,-69.69 -64.8,-69.69 -66.405,-69.69 -68.01,-69.69 -69.61500000000001,-69.69 -71.22,-69.69 -72.825,-69.69 -74.43,-69.69 -76.035,-69.69 -77.64,-80.721 -77.64,-91.752 -77.64,-102.783 -77.64,-113.814 -77.64,-124.845 -77.64,-135.876 -77.64,-146.90699999999998 -77.64,-157.938 -77.64,-168.969 -77.64,180 -77.64,179.02100000000002 -77.64,178.042 -77.64,177.063 -77.64,176.084 -77.64,175.10500000000002 -77.64,174.126 -77.64,173.147 -77.64,172.168 -77.64,171.18900000000002 -77.64,170.21 -77.64,170.21 -76.035,170.21 -74.43,170.21 -72.825,170.21 -71.22,170.21 -69.61500000000001,170.21 -68.01,170.21 -66.405,170.21 -64.8,170.21 -63.195,170.21 -61.59,171.18900000000002 -61.59,172.168 -61.59,173.147 -61.59,174.126 -61.59,175.10500000000002 -61.59,176.084 -61.59,177.063 -61.59,178.042 -61.59,179.02100000000002 -61.59,-180 -61.59))"], "date_created": "Tue, 09 Jan 2024 00:00:00 GMT", "description": "This data set contains measurements of nitrogen (\u03b415N) stable isotope values of twelve individual amino acids from modern and excavated eggshell of Ad\u00e9lie penguins (Pygoscelis adelidae) from multiple sites around the Antarctic Peninsula and Ross Sea regions of Antarctica. Stable isotope analyses were conducted using a gas chromatograph coupled to a continuous flow stable isotope ratio mass spectrometer. Radiocarbon dates of excavated eggshells were estimated using accelerator Mass Spectrometry (AMS) on bone, feather, and egg membrane tissues from the same ornithogenic layer as the eggshell and were completed at the Rafter Radiocarbon Laboratory and New Zealand (NZA), Beta Analytic, Inc. (Beta). All dates were corrected for the marine carbon reservoir effect and calibrated to calendar years before present (cal years BP) using a \u0394R of 750\u2009\u00b1\u200950 years and the MARINE13 calibration curve in Calib 7.0 (2\u03c3 range). \r\n\r\nThis data set indexes each individually analyzed eggshell sample with site (location), latitude, longitude, tissue used from radiocarbon dating, age of the sample, and nitrogen stable isotope values of individual amino acids. Details of the data set and all relevant methods are provided in Michelson et al. 2023 Limnol. Oceanogr. DOI:10.1002/lno.12446", "east": 170.21, "geometry": ["POINT(-129.74 -69.61500000000001)"], "keywords": "Adelie Penguin; Amino Acids; Antarctica; Antarctic Peninsula; Ross Sea; Stable Isotope Analysis; Trophic Position", "locations": "Ross Sea; Antarctic Peninsula; Antarctica", "north": -61.59, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "persons": "Michelson, Chantel; Polito, Michael; Wonder, Michael; Emslie, Steven; McCarthy, Matthew; Patterson, William; McMahon, Kelton", "project_titles": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators", "projects": [{"proj_uid": "p0010047", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.64, "title": "Amino acid nitrogen isotope values of modern and ancient Ad\u00e9lie penguin eggshells from the Ross Sea and Antarctic Peninsula regions", "uid": "601760", "west": -69.69}, {"awards": "0538657 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(-112.05 -79.28)"], "date_created": "Fri, 20 Oct 2023 00:00:00 GMT", "description": "Major gas components of air data set, containing d15N, d18O of O2, dO2/N2, and dAr/N2 from the WAIS Divide ice core at high resolution. These data are used to constrain surface temperature, biosphere oxygen cycling, and firn thickness through the past \u003e60 kyr.", "east": -112.05, "geometry": ["POINT(-112.05 -79.28)"], "keywords": "Antarctica; Delta 15N; Delta 18O; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Gas Records; Ice Core Records; Isotope; Nitrogen; Nitrogen Isotopes; Oxygen; Oxygen Isotope; Snow/ice; Snow/Ice; WAIS; WAIS Divide", "locations": "WAIS Divide; Antarctica; WAIS", "north": -79.28, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate", "projects": [{"proj_uid": "p0000036", "repository": "USAP-DC", "title": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.28, "title": "d15N and d18O of air in the WAIS Divide ice core", "uid": "601747", "west": -112.05}, {"awards": "1744871 Robinson, Rebecca", "bounds_geometry": null, "date_created": "Wed, 30 Aug 2023 00:00:00 GMT", "description": "This dataset is the results of 3 experiments in which the spore-forming diatom Chaetoceros socialis was grown in culture and induced into resting spores by nitrate limitation. The nitrogen isotopic composition of accumulated biomass (\u03b415Nbiomass; \u2030 vs air) and of diatom-bound organic N (\u03b415Ndb; \u2030 vs air) are reported at two timepoints from each experiment: prior to and after resting spore formation. Experiments 1 and 2 provide measurements for CRS mixed with vegetative Chaetoceros cells, while Experiment 3 provides measurements for isolated CRS. Fluorescence and nitrate concentration was tracked throughout each experiment, with dissolved silica, ammonium, and total reduced nitrogen also measured in Experiment 3.", "east": null, "geometry": null, "keywords": "Antarctica", "locations": "Antarctica; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dove, Isabel", "project_titles": "The nitrogen isotopic composition of diatom resting spores in Southern Ocean sediments: A source of bias and/or paleoenvironmental information?", "projects": [{"proj_uid": "p0010234", "repository": "USAP-DC", "title": "The nitrogen isotopic composition of diatom resting spores in Southern Ocean sediments: A source of bias and/or paleoenvironmental information?"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Dissolved nutrients, cell counts, and nitrogen isotope measurements from Chaetoceros socialis culture experiments", "uid": "601727", "west": null}, {"awards": "1744871 Robinson, Rebecca", "bounds_geometry": null, "date_created": "Thu, 24 Aug 2023 00:00:00 GMT", "description": "This dataset includes diatom assemblage and surface area data from ODP sediment core 1098B-5H-7 on the western Antarctic Peninsula. The sediments are laminated and were deposited during a period of deglaciation about 12.5-12.3 ka. Quantitative diatom assemblage counts and surface area measurements are reported for 6 samples.", "east": null, "geometry": null, "keywords": "Antarctica; Antarctic Peninsula; Glaciers/ice Sheet; Glaciers/Ice Sheet", "locations": "Antarctic Peninsula; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dove, Isabel", "project_titles": "The nitrogen isotopic composition of diatom resting spores in Southern Ocean sediments: A source of bias and/or paleoenvironmental information?", "projects": [{"proj_uid": "p0010234", "repository": "USAP-DC", "title": "The nitrogen isotopic composition of diatom resting spores in Southern Ocean sediments: A source of bias and/or paleoenvironmental information?"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "ODP Site 1098 deglacial diatom assemblage", "uid": "601723", "west": null}, {"awards": "1744871 Robinson, Rebecca", "bounds_geometry": ["POINT(-64.207 -64.86)"], "date_created": "Wed, 23 Aug 2023 00:00:00 GMT", "description": "This dataset includes measurements of opal (wt %), total organic carbon (wt %), total nitrogen (wt%), bulk nitrogen isotopic composition (d15Nbulk; \u2030 vs air), and diatom-bound nitrogen isotopic composition (d15Ndb; \u2030 vs air) from 36 samples from ODP sediment core 1098B-5H-7 on the western Antarctic Peninsula. The sediments were deposited during a period of deglaciation about 12.5-12.3 ka.", "east": -64.207, "geometry": ["POINT(-64.207 -64.86)"], "keywords": "Antarctica; Antarctic Peninsula", "locations": "Antarctic Peninsula; Antarctica; Antarctica", "north": -64.86, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dove, Isabel", "project_titles": "The nitrogen isotopic composition of diatom resting spores in Southern Ocean sediments: A source of bias and/or paleoenvironmental information?", "projects": [{"proj_uid": "p0010234", "repository": "USAP-DC", "title": "The nitrogen isotopic composition of diatom resting spores in Southern Ocean sediments: A source of bias and/or paleoenvironmental information?"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -64.86, "title": "Sediment chemistry of ODP Site 1098", "uid": "601720", "west": -64.207}, {"awards": "1744602 Iken, Katrin", "bounds_geometry": ["POLYGON((-68 -64.5,-67.5 -64.5,-67 -64.5,-66.5 -64.5,-66 -64.5,-65.5 -64.5,-65 -64.5,-64.5 -64.5,-64 -64.5,-63.5 -64.5,-63 -64.5,-63 -64.95,-63 -65.4,-63 -65.85,-63 -66.3,-63 -66.75,-63 -67.2,-63 -67.65,-63 -68.1,-63 -68.55,-63 -69,-63.5 -69,-64 -69,-64.5 -69,-65 -69,-65.5 -69,-66 -69,-66.5 -69,-67 -69,-67.5 -69,-68 -69,-68 -68.55,-68 -68.1,-68 -67.65,-68 -67.2,-68 -66.75,-68 -66.3,-68 -65.85,-68 -65.4,-68 -64.95,-68 -64.5))"], "date_created": "Tue, 10 Jan 2023 00:00:00 GMT", "description": "The purpose of this dataset was to determine the importance of macroalgal primary producers to the coastal invertebrate food webs along a gradient of sites with increasing mean annual sea ice cover. This dataset contains the carbon and nitrogen stable isotope values, in addition to carbon and nitrogen content, of various coastal primary producers and invertebrate consumers from 15 stations along the Antarctic Peninsula from 64 to 69 degree latitude south collected in 2019. Primary producers included multiple species of macroalgae, particulate organic matter (POM) as a proxy of phytoplankton production, and benthic diatoms (where they occurred). Consumers included various benthic invertebrates of different feeding types, from suspension feeders (like sponges and ascidians) to predators/omnivores (like sea stars). ", "east": -63.0, "geometry": ["POINT(-65.5 -66.75)"], "keywords": "Antarctica; Antarctic Peninsula; Biota; Carbon; Carbon Isotopes; LMG1904; Nitrogen Isotopes; Oceans", "locations": "Antarctic Peninsula; Antarctica", "north": -64.5, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Iken, Katrin", "project_titles": "Collaborative Research: Sea ice as a driver of Antarctic benthic macroalgal community composition and nearshore trophic connectivity", "projects": [{"proj_uid": "p0010104", "repository": "USAP-DC", "title": "Collaborative Research: Sea ice as a driver of Antarctic benthic macroalgal community composition and nearshore trophic connectivity"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.0, "title": "Carbon and nitrogen isotope data along a gradient at the Antarctic Peninsula", "uid": "601653", "west": -68.0}, {"awards": "1543450 Countway, Peter", "bounds_geometry": ["POLYGON((-66 -63,-65.7 -63,-65.4 -63,-65.1 -63,-64.8 -63,-64.5 -63,-64.2 -63,-63.9 -63,-63.6 -63,-63.3 -63,-63 -63,-63 -63.3,-63 -63.6,-63 -63.9,-63 -64.2,-63 -64.5,-63 -64.8,-63 -65.1,-63 -65.4,-63 -65.7,-63 -66,-63.3 -66,-63.6 -66,-63.9 -66,-64.2 -66,-64.5 -66,-64.8 -66,-65.1 -66,-65.4 -66,-65.7 -66,-66 -66,-66 -65.7,-66 -65.4,-66 -65.1,-66 -64.8,-66 -64.5,-66 -64.2,-66 -63.9,-66 -63.6,-66 -63.3,-66 -63))"], "date_created": "Tue, 03 Jan 2023 00:00:00 GMT", "description": "Dissolved Organic Carbon (DOC) and Total Dissolved Nitrogen (TDN) samples were collected from Station E (Palmer Station, Antarctica) and associated incubation experiments with Station E water. Samples were analyzed for DOC and TDN using a Shimadzu TOC-L system equipped with TNM-L for N detection. All analyses were performed in the Hansell Lab at the University of Miami, FL (USA). References for the analytical methods used for these analyses are included in a secondary tab with the uploaded data.", "east": -63.0, "geometry": ["POINT(-64.5 -64.5)"], "keywords": "Antarctica; Carbon; Dissolved Organic Carbon; Nitrogen; Palmer Station; TDN; Total Dissolved Nitrogen", "locations": "Palmer Station; Antarctica", "north": -63.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Countway, Peter; Matrai, Patricia", "project_titles": "Microbial Community Structure and Expression of Functional Genes Involved in the Seasonal Cycling of DMSP in the Southern Ocean", "projects": [{"proj_uid": "p0010120", "repository": "USAP-DC", "title": "Microbial Community Structure and Expression of Functional Genes Involved in the Seasonal Cycling of DMSP in the Southern Ocean"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -66.0, "title": "Dissolved Organic Carbon (DOC) and Total Dissolved Nitrogen (TDN) Samples from Station E (Palmer Station, Antarctica) and Associated Incubation Experiments", "uid": "601646", "west": -66.0}, {"awards": "2031442 Learman, Deric", "bounds_geometry": null, "date_created": "Thu, 08 Sep 2022 00:00:00 GMT", "description": "Shelf sediment samples were collected around the Antarctic Peninsular with the mega corer in 2020 (Nov. to Dec.). The sample locations and water depths are recorded in this dataset. These samples were used to collect data on organic matter (total organic carbon, total nitrogen, delta 13C (organic), delta 15N, and C to N ratios). Nutrient data (nitrate, nitrite, sulfate, and ammonia) and grain size analysis were collected on a subsample set (10). ", "east": null, "geometry": null, "keywords": "Antarctica; Antarctic Peninsula; Grain Size; Grain Size Analysis; Marine Geoscience; Marine Sediments; Organic Matter Geochemistry; Sediment Core Data; Shelf Sediments; Weddell Sea", "locations": "Antarctic Peninsula; Weddell Sea; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Learman, Deric", "project_titles": "RAPID: Meta-genomic and Transcriptomic Investigation of Complex Organic Matter Degradation in Antarctic Benthic Sediments", "projects": [{"proj_uid": "p0010235", "repository": "USAP-DC", "title": "RAPID: Meta-genomic and Transcriptomic Investigation of Complex Organic Matter Degradation in Antarctic Benthic Sediments"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Physical and geochemical data from shelf sediments near the Antartic Pennisula", "uid": "601607", "west": null}, {"awards": "1643664 Severinghaus, Jeffrey", "bounds_geometry": null, "date_created": "Tue, 16 Aug 2022 00:00:00 GMT", "description": "This data set consists of high-precision krypton and argon isotope measurements, along with 15N and 18O of O2. This data tests the hypothesis that the 2nd order parameter 86Krexcess (86Kr/82Kr - 40Ar/36Ar) serves as a proxy indicator of past storminess, via atmospheric pressure changes that cause barometric pumping in the firn and hence greater gravitational disequilibrium in the heavier Kr atom than in Ar. These measurements were made as part of the US-Australian Law Dome DE08-OH campaign in 2018-2019. Nitrogen and dioxygen isotopes were also measured.", "east": null, "geometry": null, "keywords": "Antarctica; Ice Core; Law Dome; Noble Gas", "locations": "Law Dome; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability", "projects": [{"proj_uid": "p0010341", "repository": "USAP-DC", "title": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Law Dome DE08-OH site noble gases in ice: testing the 86Krexcess proxy", "uid": "601597", "west": null}, {"awards": "1341464 Robinson, Rebecca; 1341432 Brzezinski, Mark", "bounds_geometry": ["POLYGON((-175 -54,-174 -54,-173 -54,-172 -54,-171 -54,-170 -54,-169 -54,-168 -54,-167 -54,-166 -54,-165 -54,-165 -55.3,-165 -56.6,-165 -57.9,-165 -59.2,-165 -60.5,-165 -61.8,-165 -63.1,-165 -64.4,-165 -65.7,-165 -67,-166 -67,-167 -67,-168 -67,-169 -67,-170 -67,-171 -67,-172 -67,-173 -67,-174 -67,-175 -67,-175 -65.7,-175 -64.4,-175 -63.1,-175 -61.8,-175 -60.5,-175 -59.2,-175 -57.9,-175 -56.6,-175 -55.3,-175 -54))"], "date_created": "Thu, 02 Jun 2022 00:00:00 GMT", "description": "This dataset contains data for particulate silicon, particulate carbon, particulate nitrogen, stable isotopes of nitrogen and stable isotopes of silicon in particulates from McLane pump profiles", "east": -165.0, "geometry": ["POINT(-170 -60.5)"], "keywords": "Antarctica; Biogenic Silica; Chemistry:sediment; Chemistry:Sediment; Diatom; Diatom Bound; Lithogenic Silica; Marine Geoscience; NBP1702; Nitrogen Isotopes; Silicon Cycle; Silicon Stable Isotope; Southern Ocean", "locations": "Southern Ocean; Southern Ocean; Antarctica", "north": -54.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "persons": "Jones, Janice L.; Closset, Ivia; Robinson, Rebecca; Brzezinski, Mark", "project_titles": "Collaborative Proposal: A Field and Laboratory Examination of the Diatom N and Si Isotope Proxies: Implications for Assessing the Southern Ocean Biological Pump", "projects": [{"proj_uid": "p0010083", "repository": "USAP-DC", "title": "Collaborative Proposal: A Field and Laboratory Examination of the Diatom N and Si Isotope Proxies: Implications for Assessing the Southern Ocean Biological Pump"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -67.0, "title": " Particulate silicon and nitrogen concentrations and isotopic composition measurements in McLane pump profiles from 67\u00b0S to 55\u00b0S latitude in the Pacific Sector of the Southern Ocean", "uid": "601576", "west": -175.0}, {"awards": "1341464 Robinson, Rebecca", "bounds_geometry": ["POLYGON((-170.4 -60.8,-170.36 -60.8,-170.32 -60.8,-170.28 -60.8,-170.24 -60.8,-170.2 -60.8,-170.16 -60.8,-170.12 -60.8,-170.08 -60.8,-170.04 -60.8,-170 -60.8,-170 -61.34,-170 -61.88,-170 -62.42,-170 -62.96,-170 -63.5,-170 -64.04,-170 -64.58,-170 -65.12,-170 -65.66,-170 -66.2,-170.04 -66.2,-170.08 -66.2,-170.12 -66.2,-170.16 -66.2,-170.2 -66.2,-170.24 -66.2,-170.28 -66.2,-170.32 -66.2,-170.36 -66.2,-170.4 -66.2,-170.4 -65.66,-170.4 -65.12,-170.4 -64.58,-170.4 -64.04,-170.4 -63.5,-170.4 -62.96,-170.4 -62.42,-170.4 -61.88,-170.4 -61.34,-170.4 -60.8))"], "date_created": "Mon, 14 Feb 2022 00:00:00 GMT", "description": "Tracking variations in the surface ocean supply and demand of nitrate, a key marine nutrient, can help constrain the contribution of biological production in driving past climate shifts. The nitrogen isotopic composition (as \u03b415N) of organic matter in marine sediments is a proxy for surface ocean nitrate supply and demand over time but it may be subject to alteration during sinking and burial. The isotopic composition of nitrogen contained in the shells, or frustules, of diatoms (\u03b415NDB) is protected and is therefore a potentially more robust tracer of nitrate use in the past. Here we show that \u03b415NDB in Southern Ocean community cultures does not depend on species composition. We found the \u03b5DB (= biomass \u03b415N - \u03b415NDB) of the community growouts was -4.8 \u00b1 0.8\u2030, more than 10\u2030 different from previous monospecific growouts, but statistically indistinguishable from previous Southern Ocean and North Pacific surface ocean observations. The two community growouts, seeded with populations from 66\u00b0 and 61\u00b0S, had distinct community compositions but indistinguishable \u03b5DB, suggesting species composition does not primarily set \u03b415NDB values in the Southern Ocean. Our results demonstrate that under nitrate-replete conditions, \u03b415NDB values of frustules sinking from the surface ocean robustly track surface ocean nitrate \u03b415N values and therefore nitrate supply and demand. ", "east": -170.0, "geometry": ["POINT(-170.2 -63.5)"], "keywords": "Antarctica; Nitrogen Isotopes; Oceans; Paleoproxies; Southern Ocean", "locations": "Southern Ocean; Antarctica", "north": -60.8, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Jones, Colin; Robinson, Rebecca; Brzezinski, Mark; Riesselman, Christina; Closset, Ivia; Kelly, Roger; Robinson, Rebecca ", "project_titles": "Collaborative Proposal: A Field and Laboratory Examination of the Diatom N and Si Isotope Proxies: Implications for Assessing the Southern Ocean Biological Pump", "projects": [{"proj_uid": "p0010083", "repository": "USAP-DC", "title": "Collaborative Proposal: A Field and Laboratory Examination of the Diatom N and Si Isotope Proxies: Implications for Assessing the Southern Ocean Biological Pump"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -66.2, "title": "Surface Southern Ocean community growouts to evaluate the diatom bound N isotope proxy", "uid": "601522", "west": -170.4}, {"awards": "1443710 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(0 -90)"], "date_created": "Thu, 03 Feb 2022 00:00:00 GMT", "description": "We present measurements gas measurements from the South Pole Ice Core, including the isotopic composition of molecular nitrogen (\u03b415N) and argon (\u03b440Ar), and the argon-nitrogen ratio (\u03b4Ar/N2). The measurements were made between approximately 490 and 1310 m depth, which is between 5 and 30 kyr BP on the SP19 Gas Chronology.\r\nThe measurements allow us to reconstruct the past amounts of gravitational and thermal fractionation in the firn and thus reconstruct past firn thickness and temperature gradient. These reconstructions are also included.\r\n", "east": 0.0, "geometry": ["POINT(0 -90)"], "keywords": "Antarctica; Argon; Argon Isotopes; Firn; Firn Temperature Gradient; Firn Thickness; Gas Isotopes; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Nitrogen; Nitrogen Isotopes; South Pole; SPICEcore", "locations": "South Pole; South Pole; Antarctica; Antarctica", "north": -90.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Morgan, Jacob; Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: Inert Gas and Methane Based Climate Records throughout the South Pole Deep Ice Core", "projects": [{"proj_uid": "p0010005", "repository": "USAP-DC", "title": "Collaborative Research: Inert Gas and Methane Based Climate Records throughout the South Pole Deep Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "SPICEcore", "south": -90.0, "title": "South Pole Ice Core Isotopes of N2 and Ar", "uid": "601517", "west": 0.0}, {"awards": "1443263 Higgins, John", "bounds_geometry": ["POLYGON((159 -75.67,159.025 -75.67,159.05 -75.67,159.075 -75.67,159.1 -75.67,159.125 -75.67,159.15 -75.67,159.175 -75.67,159.2 -75.67,159.225 -75.67,159.25 -75.67,159.25 -75.786,159.25 -75.902,159.25 -76.018,159.25 -76.134,159.25 -76.25,159.25 -76.366,159.25 -76.482,159.25 -76.598,159.25 -76.714,159.25 -76.83,159.225 -76.83,159.2 -76.83,159.175 -76.83,159.15 -76.83,159.125 -76.83,159.1 -76.83,159.075 -76.83,159.05 -76.83,159.025 -76.83,159 -76.83,159 -76.714,159 -76.598,159 -76.482,159 -76.366,159 -76.25,159 -76.134,159 -76.018,159 -75.902,159 -75.786,159 -75.67))"], "date_created": "Mon, 24 Jan 2022 00:00:00 GMT", "description": "This file includes the \u03b415N of N2, \u03b418O of O2 (\u03b418Oatm), \u03b4O2/N2, and \u03b4Ar/N2 in the S27 ice core drilled in Allan Hills Blue Ice Area.", "east": 159.25, "geometry": ["POINT(159.125 -76.25)"], "keywords": "Allan Hills; Antarctica; Blue Ice; Ice Core; Ice Core Gas Records; Isotope; Nitrogen; Oxygen", "locations": "Allan Hills; Antarctica", "north": -75.67, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Yan, Yuzhen; Bender, Michael; Higgins, John", "project_titles": "Collaborative Research: Window into the World with 40,000-year Glacial Cycles from Climate Records in Million Year-old Ice from the Allan Hills Blue Ice Area", "projects": [{"proj_uid": "p0000760", "repository": "USAP-DC", "title": "Collaborative Research: Window into the World with 40,000-year Glacial Cycles from Climate Records in Million Year-old Ice from the Allan Hills Blue Ice Area"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Allan Hills", "south": -76.83, "title": "Stable isotope composition of the trapped air in the Allan Hills S27 ice core", "uid": "601512", "west": 159.0}, {"awards": "1443585 Polito, Michael; 1443386 Emslie, Steven; 1443424 McMahon, Kelton; 1826712 McMahon, Kelton", "bounds_geometry": ["POLYGON((-37.33 -54.05,-37.192 -54.05,-37.054 -54.05,-36.916 -54.05,-36.778 -54.05,-36.64 -54.05,-36.502 -54.05,-36.364 -54.05,-36.226 -54.05,-36.088 -54.05,-35.95 -54.05,-35.95 -54.107,-35.95 -54.164,-35.95 -54.221,-35.95 -54.278,-35.95 -54.335,-35.95 -54.392,-35.95 -54.449,-35.95 -54.506,-35.95 -54.563,-35.95 -54.62,-36.088 -54.62,-36.226 -54.62,-36.364 -54.62,-36.502 -54.62,-36.64 -54.62,-36.778 -54.62,-36.916 -54.62,-37.054 -54.62,-37.192 -54.62,-37.33 -54.62,-37.33 -54.563,-37.33 -54.506,-37.33 -54.449,-37.33 -54.392,-37.33 -54.335,-37.33 -54.278,-37.33 -54.221,-37.33 -54.164,-37.33 -54.107,-37.33 -54.05))"], "date_created": "Thu, 13 Jan 2022 00:00:00 GMT", "description": "This data set contains radiometric dating measurements from two aquatic sediment cores excavated from two separate sites (Salisbury Plain and Gold Harbor) on South Georgia Island in February 2019. It also contains biological and geochemical sediment proxy values from both sediment cores, including total carbon (%), total nitrogen (%), number of penguin feathers and eggshell fragments, number of seal hairs, and \u03b413C and \u03b415N stable isotope values. Cores were sectioned at 1cm intervals, and radiometric dating analyses were conducted on sediment fractions \u003c850 \u00b5m by measuring for 210Pb and 226Ra (via 214Pb) by direct gamma counting using the high purity germanium planar detector in the Marine Geochemistry Laboratory at Louisiana State University (LSU). The 210Pbex profiles were used to calculate sedimentation rates using a steady state model that assumes constant rate of supply and constant sedimentation rate (Maiti et al., 2010). Geochemical analyses were performed on sediment fractions \u003c125 \u00b5m using an Elemental Analyzer-Isotope Ratio Mass Spectrometry (EA-IRMS) in the Stable Isotope Ecology Lab at LSU. Biological counts of feathers and hairs were determined by enumeration using a dissecting microscope of sediment fractions \u003e1000 \u00b5m. The data set also includes sediment core excavation site names and coordinates, date of excavation, sediment depth and age, and carbon to nitrogen isotopic ratios. Details of the data set and all relevant methods are provided in Kristan et al., 2021.", "east": -35.95, "geometry": ["POINT(-36.64 -54.335)"], "keywords": "Antarctica; Antarctic Fur Seal; Elemental Concentrations; King Penguin; Population Dynamics; South Atlantic Ocean; South Georgia Island; Stable Isotope Analysis; Sub-Antarctic", "locations": "South Atlantic Ocean; South Georgia Island; Sub-Antarctic; Antarctica", "north": -54.05, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Kristan, Allyson; Maiti, Kanchan; McMahon, Kelton; Polito, Michael", "project_titles": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators", "projects": [{"proj_uid": "p0010047", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -54.62, "title": "Radiometric dating, geochemical proxies, and predator biological remains obtained from aquatic sediment cores on South Georgia Island.", "uid": "601509", "west": -37.33}, {"awards": "1443263 Higgins, John", "bounds_geometry": ["POINT(159.35507 -76.73286)"], "date_created": "Tue, 02 Nov 2021 00:00:00 GMT", "description": "This file includes the d15N, O2/N2 ratio, Ar/N2 ratio, and d18O of O2 (d18Oatm) in Allan Hills ice cores (ALHIC1502 and ALHIC1503). This dataset replaces an earlier version of the elemental and isotopic composition in Allan Hills ice cores (DOI: 10.15784/601204) by adding new data from 60 depths in ALHIC1502 core (26.26 m to 175.74 m). ", "east": 159.35507, "geometry": ["POINT(159.35507 -76.73286)"], "keywords": "Allan Hills; Antarctica; Argon; Ice; Ice Core Data; Ice Core Gas Records; Isotope; Mass Spectrometry; Nitrogen; Oxygen", "locations": "Allan Hills; Antarctica", "north": -76.73286, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Yan, Yuzhen; Bender, Michael; Higgins, John", "project_titles": "Collaborative Research: Window into the World with 40,000-year Glacial Cycles from Climate Records in Million Year-old Ice from the Allan Hills Blue Ice Area", "projects": [{"proj_uid": "p0000760", "repository": "USAP-DC", "title": "Collaborative Research: Window into the World with 40,000-year Glacial Cycles from Climate Records in Million Year-old Ice from the Allan Hills Blue Ice Area"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Allan Hills", "south": -76.73286, "title": "Elemental and isotopic composition of nitrogen, oxygen, and argon in Allan Hills ice cores", "uid": "601483", "west": 159.35507}, {"awards": "1542723 Alexander, Becky", "bounds_geometry": ["POINT(-112.05 -79.28)"], "date_created": "Tue, 22 Jun 2021 00:00:00 GMT", "description": "This dataset contains measurements of nitrate oxygen (D17O) and nitrogen (d15N) isotopes from the WAIS Divide ice core (WDC06A). The time resolution is variable throughout the record. The data includes 15 discreet samples between 2900 - 67,000 years before 1950 and 305 continuous measurements between 36,000-52,000 years before 1950. The depth range is 700 - 3401 m. Each sample covered 1 m depth. The time resolution ranged from 5 years/m at the top to 200 years/m at the bottom.", "east": -112.05, "geometry": ["POINT(-112.05 -79.28)"], "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Chemistry; Ice Core Records; Nitrate; Nitrate Isotopes; WAIS Divide Ice Core; West Antarctic Ice Sheet", "locations": "West Antarctic Ice Sheet; Antarctica", "north": -79.28, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Alexander, Becky", "project_titles": "Measuring an Ice-core Proxy for Relative Oxidant Abundances over Glacial-interglacial and Rapid Climate changes in a West Antarctic Ice Core", "projects": [{"proj_uid": "p0010403", "repository": "USAP-DC", "title": "Measuring an Ice-core Proxy for Relative Oxidant Abundances over Glacial-interglacial and Rapid Climate changes in a West Antarctic Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.28, "title": "WAIS Divide ice core nitrate isotopes", "uid": "601456", "west": -112.05}, {"awards": "1543267 Brook, Edward; 1543229 Severinghaus, Jeffrey", "bounds_geometry": ["POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))"], "date_created": "Thu, 22 Oct 2020 00:00:00 GMT", "description": "Stable isotope ratios of atmospheric krypton, argon, nitrogen and oxygen were measured in late-Holocene ice core samples from nine sites in Antarctica and Greenland, for the purpose of calibrating the Kr-86 excess proxy as defined in Buizert and Severinghaus (2016).", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Bruce Plateau; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Greenland Ice Cap; Ice Core; Ice Core Chemistry; Ice Core Records; James Ross Island; Krypton; Law Dome; Low Dome Ice Core; Roosevelt Island; Siple Dome; Siple Dome Ice Core; South Pole; SPICEcore; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; South Pole; Siple Dome; Law Dome; Roosevelt Island; Greenland Ice Cap; James Ross Island; Bruce Plateau; Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "persons": "Buizert, Christo; Shackleton, Sarah; Severinghaus, Jeffrey P.; Brook, Edward J.; Baggenstos, Daniel; Bereiter, Bernhard; Etheridge, David; Bertler, Nancy; Pyne, Rebecca L.; Mulvaney, Robert; Mosley-Thompson, Ellen", "project_titles": "Collaborative research: Kr-86 as a proxy for barometric pressure variability and movement of the SH westerlies during the last\r\ndeglaciation", "projects": [{"proj_uid": "p0010037", "repository": "USAP-DC", "title": "Collaborative research: Kr-86 as a proxy for barometric pressure variability and movement of the SH westerlies during the last\r\ndeglaciation"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core; SPICEcore; Siple Dome Ice Core", "south": -90.0, "title": "Multi-site ice core Krypton stable isotope ratios", "uid": "601394", "west": -180.0}, {"awards": "1826712 McMahon, Kelton; 1443585 Polito, Michael; 1443386 Emslie, Steven; 1443424 McMahon, Kelton", "bounds_geometry": ["POINT(-54.67855 -63.434067)"], "date_created": "Fri, 24 Jul 2020 00:00:00 GMT", "description": "This data set focuses on ornithogenic soils excavated from a test pit located in an active colony of Pygoscelis spp. penguins on Platter Island in the Danger Islands archipelago along the northeastern side of the Antarctic Peninsula in December 2015. It contains radiocarbon dates of recovered penguin tissues and the estimated age of ornithogenic soils by depth. It also contains measurements of carbon (\u03b413C) and nitrogen (\u03b415N) stable isotope values of Pygoscelis spp. penguins eggshell membrane and feather samples and Antarctic fur seal (Arctocephalus gazella) hair sample recovered from these ornithogenic soils. Accelerator Mass Spectrometry (AMS) was used to obtain radiocarbon dates at the Woods Hole National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Radiocarbon Dates were corrected for the marine carbon reservoir effect and calibrated to calendar years before present (cal years BP) using a \u0394R of 750\u2009\u00b1\u200950 years and the MARINE13 calibration curve in Calib 7.04. The rbacon package ver. 2.3.9.1 in R was used to estimate age at depth of each soil level expressed as years relative to the common era (CE). Stable isotope analyses were conducted using an elemental analyzer coupled to a continuous flow stable isotope ratio mass spectrometer at Louisiana State University. The data set also includes associated data such as excavation date, location, site names, latitude/longitude, species, date of excavation, tissue used for radiocarbon dating, and carbon to nitrogen ratios. Details of the data set and all relevant methods are provided in Kalvakaalva et. al., 2020.", "east": -54.67855, "geometry": ["POINT(-54.67855 -63.434067)"], "keywords": "Antarctica; Antarctic Peninsula; Arctocephalus Gazella; Carbon; Holocene; Nitrogen; Paleoecology; Penguin; Pygoscelis Spp.; Stable Isotope Analysis; Weddell Sea", "locations": "Antarctic Peninsula; Weddell Sea; Antarctica", "north": -63.434067, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "persons": "Kalvakaalva, Rohit; Clucas, Gemma; Herman, Rachael; Polito, Michael", "project_titles": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators", "projects": [{"proj_uid": "p0010047", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -63.434067, "title": "Radiocarbon dating and stable isotope values of penguin and seal tissues recovered from ornithogenic soils on Platter Island, Danger Islands Archipelago, Antarctic Peninsula in December 2015.", "uid": "601364", "west": -54.67855}, {"awards": "0944021 Brook, Edward", "bounds_geometry": ["POLYGON((-163 -79,-162.8 -79,-162.6 -79,-162.4 -79,-162.2 -79,-162 -79,-161.8 -79,-161.6 -79,-161.4 -79,-161.2 -79,-161 -79,-161 -79.05,-161 -79.1,-161 -79.15,-161 -79.2,-161 -79.25,-161 -79.3,-161 -79.35,-161 -79.4,-161 -79.45,-161 -79.5,-161.2 -79.5,-161.4 -79.5,-161.6 -79.5,-161.8 -79.5,-162 -79.5,-162.2 -79.5,-162.4 -79.5,-162.6 -79.5,-162.8 -79.5,-163 -79.5,-163 -79.45,-163 -79.4,-163 -79.35,-163 -79.3,-163 -79.25,-163 -79.2,-163 -79.15,-163 -79.1,-163 -79.05,-163 -79))"], "date_created": "Mon, 13 Jul 2020 00:00:00 GMT", "description": "Data archived here were used to create the Roosevelt Island Ice Core gas age and ice age time scales. Data include methane concentrations, nitrogen and oxygen isotope ratios of N2 and O2, total air content and the D/H ratio of the ice. Derived products included here include ice age and gas age time scales. ", "east": -161.0, "geometry": ["POINT(-162 -79.25)"], "keywords": "Antarctica; CO2; Ice Core; Roosevelt Island", "locations": "Roosevelt Island; Roosevelt Island; Antarctica", "north": -79.0, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Brook, Edward J.; Lee, James", "project_titles": "Collaborative Research: Deglaciation of the Ross Sea Embayment - constraints from Roosevelt Island", "projects": [{"proj_uid": "p0000272", "repository": "USAP-DC", "title": "Collaborative Research: Deglaciation of the Ross Sea Embayment - constraints from Roosevelt Island"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -79.5, "title": "Roosevelt Island Ice Core Time Scale and Associated Data", "uid": "601359", "west": -163.0}, {"awards": "1341464 Robinson, Rebecca; 1341432 Brzezinski, Mark", "bounds_geometry": ["POLYGON((-175 -54,-174 -54,-173 -54,-172 -54,-171 -54,-170 -54,-169 -54,-168 -54,-167 -54,-166 -54,-165 -54,-165 -55.3,-165 -56.6,-165 -57.9,-165 -59.2,-165 -60.5,-165 -61.8,-165 -63.1,-165 -64.4,-165 -65.7,-165 -67,-166 -67,-167 -67,-168 -67,-169 -67,-170 -67,-171 -67,-172 -67,-173 -67,-174 -67,-175 -67,-175 -65.7,-175 -64.4,-175 -63.1,-175 -61.8,-175 -60.5,-175 -59.2,-175 -57.9,-175 -56.6,-175 -55.3,-175 -54))"], "date_created": "Thu, 09 Apr 2020 00:00:00 GMT", "description": "This dataset contains profiles of water column particulate organic carbon (POC), total particulate nitrogen (TPN), biogenic silica, and d15N of TPN from McLane pump casts (4 depths/cast).", "east": -165.0, "geometry": ["POINT(-170 -60.5)"], "keywords": "Antarctica; Biogenic Silica; Nitrogen Isotopes; Southern Ocean", "locations": "Southern Ocean; Antarctica", "north": -54.0, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Robinson, Rebecca; Brzezinski, Mark", "project_titles": "Collaborative Proposal: A Field and Laboratory Examination of the Diatom N and Si Isotope Proxies: Implications for Assessing the Southern Ocean Biological Pump", "projects": [{"proj_uid": "p0010083", "repository": "USAP-DC", "title": "Collaborative Proposal: A Field and Laboratory Examination of the Diatom N and Si Isotope Proxies: Implications for Assessing the Southern Ocean Biological Pump"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -67.0, "title": "Particle composition measurements from along 170\u00b0W between 67-54\u00b0S", "uid": "601276", "west": -175.0}, {"awards": "1443470 Aydin, Murat", "bounds_geometry": ["POINT(-98.16 -89.99)"], "date_created": "Wed, 01 Apr 2020 00:00:00 GMT", "description": "The data file includes the results of the carbonyl sulfide (COS), methyl chloride (CH3Cl), and methyl bromide (CH3Br) measurements from the SPC14 ice core drilled at the South Pole as part of the SPICEcore project. There are a total of 425 measurements. The file is an Excel worksheet saved in .xlsx format. The are seven columns: depth (m), COS (ppt), err (ppt), CH3Cl (ppt), err (ppt), CH3Br (ppt), err (ppt). The depth column is the mid-depth of the samples calculated from top and bottom depth measurements conducted during the CPL. All measurements are reported as dry molar mixing ratios in parts per trillion (ppt). The err column after the data for each compound is the plus/minus 1 sigma uncertainty estimate in ppt\u2019s and it is the cumulative uncertainty based on the precision of the analytical measurement plus the uncertainty that arises from the variability in the background (blank) trace gas levels in the ice core extraction system. The background trace gas levels in the ice core gas extraction and the analytical systems are determined by regularly conducting nitrogen (N2) blanks. Please refer to Aydin et al. [JGR doi:10.1029/2006JD008027, 2007] for details of the measurement methods and the calibration practices. A few instances of missing data are denoted by -999. Contact with the PI encouraged before data usage.", "east": -98.16, "geometry": ["POINT(-98.16 -89.99)"], "keywords": "Antarctica", "locations": "Antarctica; Antarctica", "north": -89.99, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Aydin, Murat", "project_titles": "Carbonyl Sulfide, Methyl Chloride, and Methyl Bromide Measurements in the New Intermediate-depth South Pole Ice Core", "projects": [{"proj_uid": "p0010089", "repository": "USAP-DC", "title": "Carbonyl Sulfide, Methyl Chloride, and Methyl Bromide Measurements in the New Intermediate-depth South Pole Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "SPICEcore", "south": -89.99, "title": "SPC14 carbonyl sulfide, methyl chloride, and methyl bromide measurements from South Pole, Antarctica", "uid": "601270", "west": -98.16}, {"awards": "1826712 McMahon, Kelton; 1443424 McMahon, Kelton; 1443585 Polito, Michael; 1443386 Emslie, Steven", "bounds_geometry": ["POLYGON((162 -72,162.9 -72,163.8 -72,164.7 -72,165.6 -72,166.5 -72,167.4 -72,168.3 -72,169.2 -72,170.1 -72,171 -72,171 -72.6,171 -73.2,171 -73.8,171 -74.4,171 -75,171 -75.6,171 -76.2,171 -76.8,171 -77.4,171 -78,170.1 -78,169.2 -78,168.3 -78,167.4 -78,166.5 -78,165.6 -78,164.7 -78,163.8 -78,162.9 -78,162 -78,162 -77.4,162 -76.8,162 -76.2,162 -75.6,162 -75,162 -74.4,162 -73.8,162 -73.2,162 -72.6,162 -72))"], "date_created": "Tue, 03 Mar 2020 00:00:00 GMT", "description": "This data set contains measurements of carbon (\u03b413C) and nitrogen (\u03b415N) stable isotope values of feather, skin, bone, and toenail samples of mummified Ad\u00e9lie penguin chick remains excavated from multiple sites around the Ross Sea region of Antarctica between 2004 and 2016, as well as the same measurements for modern Ad\u00e9lie chicks collected from the surface of Cape Hallett and Adelie Cove in January 2016. Stable isotope analyses were conducted using an elemental analyzer coupled to a continuous flow stable isotope ratio mass spectrometer. Where possible, accelerator Mass Spectrometry (AMS) radiocarbon dates on selected mummy tissues were completed at the Rafter Radiocarbon Laboratory, New Zealand (NZA), Beta Analytic, Inc. (Beta), the University of Georgia Center for Applied Isotope Studies (UGAMS), and Woods Hole National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. All dates were corrected for the marine carbon reservoir effect and calibrated to calendar years before present (cal years BP) using a \u0394R of 750\u2009\u00b1\u200950 years and the MARINE13 calibration curve in Calib 7.0 (2\u03c3 range). \r\nThe data set also includes excavation/collection site names and latitude/longitude, date of excavation/collection, tissue used for radiocarbon dating, and carbon to nitrogen ratios. Details of the data set and all relevant methods are provided in Kristan et. al., 2019.\r\n", "east": 171.0, "geometry": ["POINT(166.5 -75)"], "keywords": "Abandoned Colonies; Antarctica; Holocene; Penguin; Ross Sea; Stable Isotope Analysis", "locations": "Antarctica; Ross Sea; Antarctica", "north": -72.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "persons": "Kristan, Allyson; Emslie, Steven; Patterson, William", "project_titles": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators", "projects": [{"proj_uid": "p0010047", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Radioisotope dates and carbon (\u03b413C) and nitrogen (\u03b415N) stable isotope values from modern and mummified Ad\u00e9lie Penguin chick carcasses and tissue from the Ross Sea, Antarctica", "uid": "601263", "west": 162.0}, {"awards": "1826712 McMahon, Kelton; 1443424 McMahon, Kelton; 1443386 Emslie, Steven; 1443585 Polito, Michael", "bounds_geometry": ["POLYGON((-63.56 -60.72,-61.664 -60.72,-59.768 -60.72,-57.872 -60.72,-55.976 -60.72,-54.08 -60.72,-52.184 -60.72,-50.288 -60.72,-48.392 -60.72,-46.496 -60.72,-44.6 -60.72,-44.6 -61.106,-44.6 -61.492,-44.6 -61.878,-44.6 -62.264,-44.6 -62.65,-44.6 -63.036,-44.6 -63.422,-44.6 -63.808,-44.6 -64.194,-44.6 -64.58,-46.496 -64.58,-48.392 -64.58,-50.288 -64.58,-52.184 -64.58,-54.08 -64.58,-55.976 -64.58,-57.872 -64.58,-59.768 -64.58,-61.664 -64.58,-63.56 -64.58,-63.56 -64.194,-63.56 -63.808,-63.56 -63.422,-63.56 -63.036,-63.56 -62.65,-63.56 -62.264,-63.56 -61.878,-63.56 -61.492,-63.56 -61.106,-63.56 -60.72))"], "date_created": "Tue, 17 Dec 2019 00:00:00 GMT", "description": "This data set contains measurements of nitrogen (\u03b415N) stable isotope values of twelve individual amino acids from breast feathers of gentoo penguins (Pygoscelis papua) and chinstrap penguins (Pygoscelis antarctica) collected from museum archives between the 1930s and 2010s. Stable isotope analyses were conducted using a gas chromatograph coupled to a continuous flow stable isotope ratio mass spectrometer. The data set also includes trophic positions of penguins calculated from individual amino acid \u03b415N values.\r\nThe data set indexes each individual penguin with species, collection institution, catalog number, sex, locality, latitude, longitude, year of sample collection, nitrogen isotope ratios, and calculated trophic position. Details of the data set and all relevant methods are provided in McMahon et al. 2020 Proc Natl Acad Sci DOI: 10.1073/pnas.1913093116 ", "east": -44.6, "geometry": ["POINT(-54.08 -62.65)"], "keywords": "Amino Acids; Antarctica; Antarctic Peninsula; Biota; Isotope Data; Nitrogen Isotopes; Oceans; Penguin; Southern Ocean; Stable Isotope Analysis", "locations": "Antarctic Peninsula; Southern Ocean; Antarctica; Antarctica", "north": -60.72, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "persons": "McMahon, Kelton; Polito, Michael", "project_titles": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators", "projects": [{"proj_uid": "p0010047", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -64.58, "title": "Amino acid nitrogen isotope values of penguins from the Antarctic Peninsula region 1930s to 2010s", "uid": "601232", "west": -63.56}, {"awards": "1443585 Polito, Michael; 1443386 Emslie, Steven; 1443424 McMahon, Kelton; 1826712 McMahon, Kelton", "bounds_geometry": ["POLYGON((-63 -60,-62.1 -60,-61.2 -60,-60.3 -60,-59.4 -60,-58.5 -60,-57.6 -60,-56.7 -60,-55.8 -60,-54.9 -60,-54 -60,-54 -60.4,-54 -60.8,-54 -61.2,-54 -61.6,-54 -62,-54 -62.4,-54 -62.8,-54 -63.2,-54 -63.6,-54 -64,-54.9 -64,-55.8 -64,-56.7 -64,-57.6 -64,-58.5 -64,-59.4 -64,-60.3 -64,-61.2 -64,-62.1 -64,-63 -64,-63 -63.6,-63 -63.2,-63 -62.8,-63 -62.4,-63 -62,-63 -61.6,-63 -61.2,-63 -60.8,-63 -60.4,-63 -60))"], "date_created": "Fri, 13 Sep 2019 00:00:00 GMT", "description": "This data set contains measurements of carbon (\u03b413C) and nitrogen (\u03b415N) stable isotope values of whole-body Antarctic krill (Euphausia superba) collected from trawl surveys of waters surrounding the South Shetland Islands and the northern Antarctic Peninsula during the 2006-07 and 2008-90 Austral summers. Stable isotope analyses were conducted using an elemental analyzer coupled to a continuous flow stable isotope ratio mass spectrometer. Individual krill were lipid-extracted prior to analyses. The data set also includes latitude, longitude, month, and year of sample collection, standard length of the krill to the nearest mm, age class, sex, and carbon to nitrogen ratios. Details of the data set and all relevant methods are provided in Polito et al., 2013 and Polito et al., 2019.", "east": -54.0, "geometry": ["POINT(-58.5 -62)"], "keywords": "Antarctica; Antarctic Krill; Antarctic Peninsula; Biota; Carbon Isotopes; Isotope Data; Krill; Nitrogen Isotopes; Oceans; Southern Ocean; Stable Isotope Analysis", "locations": "Antarctic Peninsula; Southern Ocean; Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "persons": "Polito, Michael", "project_titles": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators", "projects": [{"proj_uid": "p0010047", "repository": "USAP-DC", "title": "Collaborative Research: Investigating Holocene Shifts in the Diets and Paleohistory of Antarctic Krill Predators"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -64.0, "title": "Carbon and nitrogen stable isotope values of Antarctic Krill from the South Shetland Islands and the northern Antarctic Peninsula 2007 and 2009", "uid": "601210", "west": -63.0}, {"awards": "1443336 Osterberg, Erich", "bounds_geometry": ["POINT(-180 -90)"], "date_created": "Thu, 29 Aug 2019 00:00:00 GMT", "description": "The South Pole Ice Core (SPICEcore) was drilled in 2014-2016 to provide a detailed multi-proxy archive of paleoclimate conditions in East Antarctica during the Holocene and late Pleistocene. Interpretation of these records requires an accurate depth-age relationship. Here, we present the SP19 timescale for the age of the ice of SPICEcore. SP19 is synchronized to the WD2014 chronology from the West Antarctic Ice Sheet Divide (WAIS Divide) ice core using stratigraphic matching of 251 volcanic events. These events indicate an age of 54,302 +/- 519 years BP (before the year 1950) at the bottom of SPICEcore. Annual layers identified in sodium and magnesium ions to 11,341 BP were used to interpolate between stratigraphic volcanic tie points, yielding an annually-resolved chronology through the Holocene. Estimated timescale uncertainty during the Holocene is less than 18 years relative to WD2014, with the exception of the interval between 1800 to 3100 BP when uncertainty estimates reach +/- 25 years due to widely spaced volcanic tie points. Prior to the Holocene, uncertainties remain within 124 years relative to WD2014. Results show an average Holocene accumulation rate of 7.4 cm/yr (water equivalent). The time variability of accumulation rate is consistent with expectations for steady-state ice flow through the modern spatial pattern of accumulation rate. Time variations in nitrate concentration, nitrate seasonal amplitude, and \u03b415N of N2 in turn are as expected for the accumulation-rate variations. The highly variable yet well-constrained Holocene accumulation history at the site can help improve scientific understanding of deposition-sensitive climate proxies such as \u03b415N of N2 and photolyzed chemical compounds.", "east": -180.0, "geometry": ["POINT(-180 -90)"], "keywords": "Antarctica; Calcium (ca); Chemistry:ice; Chemistry:Ice; Depth; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciochemistry; Glaciology; Ice; Ice Core; Ice Core Chemistry; Ice Core Data; Ice Core Records; Ice Core Stratigraphy; Nitrate; Nitrogen Isotopes; Paleoclimate; Snow/ice; Snow/Ice; South Pole; SPICEcore", "locations": "South Pole; Antarctica", "north": -90.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Winski, Dominic A.; Fudge, T. J.; Dunbar, Nelia; Buizert, Christo; Bay, Ryan; Souney, Joseph Jr.; Sigl, Michael; McConnell, Joseph; Fegyveresi, John; Cole-Dai, Jihong; Thundercloud, Zayta; Cox, Thomas S.; Kreutz, Karl; Epifanio, Jenna; Ortman, Nikolas; Brook, Edward J.; Beaudette, Ross; Sowers, Todd A.; Steig, Eric J.; Morris, Valerie; Kahle, Emma; Ferris, David G.; Aydin, Murat; Nicewonger, Melinda R.; Casey, Kimberly A.; Alley, Richard; Waddington, Edwin D.; Osterberg, Erich; Severinghaus, Jeffrey P.; Jones, Tyler R.; Iverson, Nels", "project_titles": "Collaborative Research: South Pole Ice Core Chronology and Climate Records using Chemical and Microparticle Measurements", "projects": [{"proj_uid": "p0010051", "repository": "USAP-DC", "title": "Collaborative Research: South Pole Ice Core Chronology and Climate Records using Chemical and Microparticle Measurements"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "SPICEcore", "south": -90.0, "title": "The South Pole Ice Core (SPICEcore) chronology and supporting data", "uid": "601206", "west": -180.0}, {"awards": "1246148 Severinghaus, Jeffrey; 1245821 Brook, Edward; 1245659 Petrenko, Vasilii", "bounds_geometry": ["POINT(162.167 -77.733)"], "date_created": "Mon, 12 Aug 2019 00:00:00 GMT", "description": "New ice cores retrieved from the Taylor Glacier (Antarctica) blue ice area contain ice and air spanning the Marine Isotope Stage (MIS) 5-4 transition, a period of global cooling and ice sheet expansion. We determine chronologies for the ice and air bubbles in the new ice cores by visually matching variations in gas- and ice- phase tracers to preexisting ice core records. The chronologies reveal an ice age-gas age difference (\u0394age) approaching 10 ka during MIS 4, implying very low snow accumulation in the Taylor Glacier accumulation zone. A revised chronology for the analagous section of the Taylor Dome ice core (84 to 55 ka), located to the south of the Taylor Glacier accumulation zone, shows that \u0394age did not exceed 3 ka. The difference in \u0394age between the two records during MIS 4 is similar in magnitude but opposite in direction to what is observed at the Last Glacial Maximum. This relationship implies that a spatial gradient in snow accumulation existed across the Taylor Dome region during MIS 4 that was oriented in the opposite direction of the accumulation gradient during the Last Glacial Maximum.", "east": 162.167, "geometry": ["POINT(162.167 -77.733)"], "keywords": "Antarctica; Blue Ice; Chemistry:ice; Chemistry:Ice; CO2; Dust; Gas; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Mass Spectrometer; Methane; Nitrogen Isotopes; Oxygen Isotope; Paleoclimate; Snow/ice; Snow/Ice; Taylor Dome; Taylor Dome Ice Core", "locations": "Taylor Dome; Antarctica", "north": -77.733, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "persons": "Menking, James; Brook, Edward J.; Marcott, Shaun; Barker, Stephen; Shackleton, Sarah; Dyonisius, Michael; Petrenko, Vasilii; McConnell, Joseph; Rhodes, Rachel; Bauska, Thomas; Baggenstos, Daniel; Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.733, "title": "Gas and Dust Measurements for Taylor Glacier and Taylor Dome Ice Cores", "uid": "601198", "west": 162.167}, {"awards": "1443680 Smith, Craig", "bounds_geometry": ["POLYGON((-65 -64,-64.7 -64,-64.4 -64,-64.1 -64,-63.8 -64,-63.5 -64,-63.2 -64,-62.9 -64,-62.6 -64,-62.3 -64,-62 -64,-62 -64.1,-62 -64.2,-62 -64.3,-62 -64.4,-62 -64.5,-62 -64.6,-62 -64.7,-62 -64.8,-62 -64.9,-62 -65,-62.3 -65,-62.6 -65,-62.9 -65,-63.2 -65,-63.5 -65,-63.8 -65,-64.1 -65,-64.4 -65,-64.7 -65,-65 -65,-65 -64.9,-65 -64.8,-65 -64.7,-65 -64.6,-65 -64.5,-65 -64.4,-65 -64.3,-65 -64.2,-65 -64.1,-65 -64))"], "date_created": "Wed, 13 Feb 2019 00:00:00 GMT", "description": "Sediment organic carbon and organic nitrogen content (percent mass) in 6 depth intervals (0-1cm, 1-2cm, 3-4cm, 5-6cm, 7-8cm , 9-10cm) in sediment cores collected by OSIL Megacore (10 cm diameter tubes) along the five-station FjordEco Transect from inner Andvord Bay to the open continental shelf at FOODBANCS Station B. \r\n", "east": -62.0, "geometry": ["POINT(-63.5 -64.5)"], "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Snow/ice; Snow/Ice", "locations": "Antarctica", "north": -64.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Smith, Craig", "project_titles": "Collaborative Research: Fjord Ecosystem Structure and Function on the West Antarctic Peninsula - Hotspots of Productivity and Biodiversity? (FjordEco)", "projects": [{"proj_uid": "p0010010", "repository": "USAP-DC", "title": "Collaborative Research: Fjord Ecosystem Structure and Function on the West Antarctic Peninsula - Hotspots of Productivity and Biodiversity? (FjordEco)"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "FjordEco", "south": -65.0, "title": "Fjord-Eco_Sediment_OrgC_OrgN_Data - Craig Smith", "uid": "601157", "west": -65.0}, {"awards": "1443710 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(0 -90)"], "date_created": "Sat, 02 Feb 2019 00:00:00 GMT", "description": "This data set includes major atmospheric gas and gas isotope data from the SPICECORE project, which recovered a 1750-m ice core at the South Pole in 2015. 15N, 18O of O2, O2/N2, and Ar/N2 are included.", "east": 0.0, "geometry": ["POINT(0 -90)"], "keywords": "Antarctica; Antarctic Ice Sheet; Chemistry:gas; Chemistry:Gas; Chemistry:ice; Chemistry:Ice; Delta 18O; Dole Effect; Firn Thickness; Gas Isotopes; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Gravitational Settling; Ice; Ice Core Chemistry; Ice Core Data; Ice Core Gas Records; Ice Core Records; Inert Gases; Nitrogen; Nitrogen Isotopes; Oxygen; Oxygen Isotope; Snow/ice; Snow/Ice; South Pole; SPICEcore", "locations": "Antarctic Ice Sheet; South Pole; Antarctica", "north": -90.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: Inert Gas and Methane Based Climate Records throughout the South Pole Deep Ice Core", "projects": [{"proj_uid": "p0010005", "repository": "USAP-DC", "title": "Collaborative Research: Inert Gas and Methane Based Climate Records throughout the South Pole Deep Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "SPICEcore", "south": -90.0, "title": "South Pole (SPICECORE) 15N, 18O, O2/N2 and Ar/N2", "uid": "601152", "west": 0.0}, {"awards": "1430550 Domack, Eugene", "bounds_geometry": ["POLYGON((120 -66,120.1 -66,120.2 -66,120.3 -66,120.4 -66,120.5 -66,120.6 -66,120.7 -66,120.8 -66,120.9 -66,121 -66,121 -66.4,121 -66.8,121 -67.2,121 -67.6,121 -68,121 -68.4,121 -68.8,121 -69.2,121 -69.6,121 -70,120.9 -70,120.8 -70,120.7 -70,120.6 -70,120.5 -70,120.4 -70,120.3 -70,120.2 -70,120.1 -70,120 -70,120 -69.6,120 -69.2,120 -68.8,120 -68.4,120 -68,120 -67.6,120 -67.2,120 -66.8,120 -66.4,120 -66))"], "date_created": "Fri, 18 Aug 2017 00:00:00 GMT", "description": "Bulk sediment carbon and nitrogen data data for Paleocene sediments collected on Totten continental shelf, East Antarctica. ", "east": 121.0, "geometry": ["POINT(120.5 -68)"], "keywords": "Antarctica; Carbon; Chemistry:sediment; Chemistry:Sediment; Geochemistry; Marine Sediments; NBP1402; Nitrogen; Oceans; Sabrina Coast; Sediment Core; Southern Ocean; Totten Glacier", "locations": "Sabrina Coast; Totten Glacier; Southern Ocean; Antarctica", "north": -66.0, "nsf_funding_programs": "Antarctic Integrated System Science", "persons": "Smith, Catherine; Shevenell, Amelia; Domack, Eugene Walter", "project_titles": "Collaborative Research: Totten Glacier System and the Marine Record of Cryosphere - Ocean Dynamics", "projects": [{"proj_uid": "p0000008", "repository": "USAP-DC", "title": "Collaborative Research: Totten Glacier System and the Marine Record of Cryosphere - Ocean Dynamics"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -70.0, "title": "NBP14-02 JPC-55 Bulk Sediment Carbon and Nitrogen data", "uid": "601044", "west": 120.0}, {"awards": "0538657 Severinghaus, Jeffrey", "bounds_geometry": ["POLYGON((-113 -79,-112.8 -79,-112.6 -79,-112.4 -79,-112.2 -79,-112 -79,-111.8 -79,-111.6 -79,-111.4 -79,-111.2 -79,-111 -79,-111 -79.1,-111 -79.2,-111 -79.3,-111 -79.4,-111 -79.5,-111 -79.6,-111 -79.7,-111 -79.8,-111 -79.9,-111 -80,-111.2 -80,-111.4 -80,-111.6 -80,-111.8 -80,-112 -80,-112.2 -80,-112.4 -80,-112.6 -80,-112.8 -80,-113 -80,-113 -79.9,-113 -79.8,-113 -79.7,-113 -79.6,-113 -79.5,-113 -79.4,-113 -79.3,-113 -79.2,-113 -79.1,-113 -79))"], "date_created": "Fri, 18 Aug 2017 00:00:00 GMT", "description": "This data set contains measurements of d18Oatm (d18O of O2), d15N, dAr/N2, and dO2/N2 in gas bubbles from the WAIS Divide ice core. The time resolution is variable throughout the record but is ~100 years on average (from 65 ka to present). All measurements were made in the Noble Gas Isotope Laboratory at Scripps Institution of Oceanography (La Jolla, CA). The data set includes all replicate measurements as well as replicate-mean values and a calculation of measurement precision (pooled standard deviation). The second sheet of this data set includes fitted d18Oatm curves for the past 50 ka from both the WAIS Divide and Siple Dome Antarctic ice cores, both on the WD2014 timescale (Buizert et al., 2015). The second sheet also includes calculations of the time derivative of d18Oatm and d e LAND in both ice cores individual as well as in a composite record. Details of the entire data set and all relevant methods are provided in Seltzer et al., 2017.", "east": -111.0, "geometry": ["POINT(-112 -79.5)"], "keywords": "Antarctica; Chemistry:ice; Chemistry:Ice; Gas; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Isotope; WAIS Divide Ice Core", "locations": "Antarctica", "north": -79.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Seltzer, Alan; Severinghaus, Jeffrey P.", "project_titles": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate", "projects": [{"proj_uid": "p0000036", "repository": "USAP-DC", "title": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -80.0, "title": "WAIS Divide d18Oatm and Siple Dome/WAIS Divide composite and individual delta epsilon LAND", "uid": "601041", "west": -113.0}, {"awards": "1141993 Rich, Jeremy", "bounds_geometry": ["POINT(-64.05 -64.77)"], "date_created": "Mon, 12 Jun 2017 00:00:00 GMT", "description": "From winter to late summer during the 2013-2014 season at Palmer Station, Antarctica, we collected weekly to bi-weekly samples of the seawater intake to measure changes in bacterial community composition, based on sequencing 16S rRNA genes. Along with the sequences, we collected data on environmental parameters in the samples (chlorophyll a, bacterial production, salinity, nutrients, bacterial cell numbers, and particulate organic carbon and nitrogen).", "east": -64.05, "geometry": ["POINT(-64.05 -64.77)"], "keywords": "Antarctica; Antarctic Peninsula; Bacteria; Biota; Genetic; Geochemistry; Palmer Station; Sample/collection Description; Sample/Collection Description; Sea Water; Southern Ocean", "locations": "Antarctic Peninsula; Palmer Station; Antarctica; Southern Ocean", "north": -64.77, "nsf_funding_programs": null, "persons": "Rich, Jeremy", "project_titles": "Collaborative Research: Microbial Community Assembly in Coastal Waters of the Western Antarctic Peninsula", "projects": [{"proj_uid": "p0000409", "repository": "USAP-DC", "title": "Collaborative Research: Microbial Community Assembly in Coastal Waters of the Western Antarctic Peninsula"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -64.77, "title": "Seasonal Succession of Bacterial Communities in Coastal Waters of the Western Antarctic Peninsula", "uid": "601032", "west": -64.05}, {"awards": "0538049 Steig, Eric", "bounds_geometry": ["POINT(-112.085 -79.5)"], "date_created": "Thu, 09 Mar 2017 00:00:00 GMT", "description": "This data set contain oxygen isotopes of sulfate and nitrate and nitrogen isotopes of nitrate from the WAIS Divide ice core from the surface to 577 m depth at varying resolution", "east": -112.085, "geometry": ["POINT(-112.085 -79.5)"], "keywords": "Antarctica; Chemistry:ice; Chemistry:Ice; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Nitrate; Oxygen Isotope; Sulfate; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -79.5, "nsf_funding_programs": null, "persons": "Alexander, Becky; Steig, Eric J.", "project_titles": "Collaborative Research: Multiple-isotope Analysis of Nitrate and Sulfate in the West Antarctic Ice Sheet Divide Ice Core", "projects": [{"proj_uid": "p0000020", "repository": "USAP-DC", "title": "Collaborative Research: Multiple-isotope Analysis of Nitrate and Sulfate in the West Antarctic Ice Sheet Divide Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.5, "title": "WAIS Divide sulfate and nitrate isotopes", "uid": "601007", "west": -112.085}, {"awards": "0539232 Cuffey, Kurt", "bounds_geometry": ["POINT(-112.083 -79.467)"], "date_created": "Thu, 12 Jan 2017 00:00:00 GMT", "description": "This dataset contains the temperature reconstruction at the West Antarctic Ice Sheet (WAIS) Divide reported by Cuffey et al. (2016) in PNAS. Five files contain 1) the primary reconstruction (Eq. 2 of that publication), combining information from borehole temperatures, deuterium isotopic content of ice, and nitrogen-15 content of trapped diatomic nitrogen gas; 2) the primary reconstruction with higher-frequency content restored; 3) the lower limit of the primary reconstruction; 4) the upper limit of the primary reconstruction; and 5) and the primary reconstruction with added perturbations.", "east": -112.083, "geometry": ["POINT(-112.083 -79.467)"], "keywords": "Antarctica; Chemistry:fluid; Chemistry:Fluid; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Nitrogen; Paleoclimate; Temperature; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -79.467, "nsf_funding_programs": null, "persons": "Cuffey, Kurt M.", "project_titles": "Collaborative Research: Physical Properties of the WAIS Divide Deep Core", "projects": [{"proj_uid": "p0000038", "repository": "USAP-DC", "title": "Collaborative Research: Physical Properties of the WAIS Divide Deep Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.467, "title": "Temperature Reconstruction at the West Antarctic Ice Sheet Divide", "uid": "600377", "west": -112.083}, {"awards": "0538657 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(-38.5 -76.2)"], "date_created": "Tue, 27 Oct 2015 00:00:00 GMT", "description": "This data set contains the results of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) performed on an archive of the GISP2 ice core containing the rapid climate warming of Dansgaard-Oeschger Event 21.", "east": -38.5, "geometry": ["POINT(-38.5 -76.2)"], "keywords": "Arctic; Geochemistry; GISP; Glaciers/ice Sheet; Glaciers/Ice Sheet; Ice Core Records; Paleoclimate", "locations": "Arctic", "north": -76.2, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Haines, Skylar; Mayewski, Paul A.; Kurbatov, Andrei V.", "project_titles": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate", "projects": [{"proj_uid": "p0000036", "repository": "USAP-DC", "title": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -76.2, "title": "Ultra-High Resolution LA-ICP-MS Results: DO-21 Rapid Warming Event", "uid": "609635", "west": -38.5}, {"awards": "0538657 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(-112.08 -79.47)"], "date_created": "Tue, 20 Oct 2015 00:00:00 GMT", "description": "This data set is a low-resolution set of measurements of d15N of N2 and d18O of O2, along with dO2/N and dAr/N2 supporting data, in the WAIS Divide 3405 m long ice core recovered in 2011. Data are distributed via FTP.", "east": -112.08, "geometry": ["POINT(-112.08 -79.47)"], "keywords": "Antarctica; Chemistry:fluid; Chemistry:Fluid; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Paleoclimate; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -79.47, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate", "projects": [{"proj_uid": "p0000036", "repository": "USAP-DC", "title": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.47, "title": "Low-res d15N and d18O of O2 in the WAIS Divide 06A Deep Core", "uid": "609660", "west": -112.08}, {"awards": "0538657 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(-112.125 -79.463)"], "date_created": "Mon, 08 Jun 2015 00:00:00 GMT", "description": "This data set includes borehole temperature measurements performed in January 2008 and January 2009 at the West Antarctic Ice sheet divide from the 300 m hole WDC05A.", "east": -112.125, "geometry": ["POINT(-112.125 -79.463)"], "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Temperature; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -79.463, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.; Orsi, Anais J.", "project_titles": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate", "projects": [{"proj_uid": "p0000036", "repository": "USAP-DC", "title": "Nitrogen and Oxygen Gas Isotopes in the WAIS Divide Ice Core as Constraints on Chronology, Temperature, and Accumulation Rate"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -79.463, "title": "Borehole Temperature Measurement in WDC05A in January 2008 and January 2009", "uid": "609637", "west": -112.125}, {"awards": "0838996 Hollibaugh, James", "bounds_geometry": ["POLYGON((-79 -63,-77.5 -63,-76 -63,-74.5 -63,-73 -63,-71.5 -63,-70 -63,-68.5 -63,-67 -63,-65.5 -63,-64 -63,-64 -63.8,-64 -64.6,-64 -65.4,-64 -66.2,-64 -67,-64 -67.8,-64 -68.6,-64 -69.4,-64 -70.2,-64 -71,-65.5 -71,-67 -71,-68.5 -71,-70 -71,-71.5 -71,-73 -71,-74.5 -71,-76 -71,-77.5 -71,-79 -71,-79 -70.2,-79 -69.4,-79 -68.6,-79 -67.8,-79 -67,-79 -66.2,-79 -65.4,-79 -64.6,-79 -63.8,-79 -63))"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "Ammonia oxidation is the first step in the conversion of regenerated nitrogen to dinitrogen gas, a 3-step pathway mediated by 3 distinct guilds of bacteria and archaea. Ammonia oxidation and the overall process of nitrification-denitrification have received relatively little attention in polar oceans where the effects of climate change on biogeochemical rates are likely to be pronounced. Previous work on Ammonia Oxidizing Archaea (AOA) in the Palmer LTER study area West of the Antarctic Peninsula (WAP), has suggested strong vertical segregation of crenarchaeote metabolism, with the \u0027winter water\u0027 (WW, ~50-100 m depth range) dominated by non-AOA crenarchaeotes, while Crenarchaeota populations in the \u0027circumpolar deep water\u0027 (CDW), which lies immediately below the winter water (150-3500 m), are dominated by AOA. Analysis of a limited number of samples from the Arctic Ocean did not reveal a comparable vertical segregation of AOA, and suggested that AOA and Crenarchaeota abundance is much lower there than in the Antarctic. These findings led to 3 hypotheses that will be tested in this project: 1) the apparent low abundance of Crenarchaeota and AOA in Arctic Ocean samples may be due to spatial or temporal variability in populations; 2) the WW population of Crenarchaeota in the WAP is dominated by a heterotroph; 3) the WW population of Crenarchaeota in the WAP \u0027grows in\u0027 during spring and summer after this water mass forms.\n\nThe study will contribute substantially to understanding an important aspect of the nitrogen cycle in the Palmer LTER (Long Term Ecological Research) study area by providing insights into the ecology and physiology of AOA. The natural segregation of crenarchaeote phenotypes in waters of the WAP, coupled with metagenomic studies in progress in the same area by others (A. Murray, H. Ducklow), offers the possibility of major breakthroughs in understanding of the metabolic capabilities of these organisms. This knowledge is needed to model how water column nitrification will respond to changes in polar ecosystems accompanying global climate change. The Principal Investigator will participate fully in the education and outreach efforts of the Palmer LTER, including making highlights of our findings available for posting to their project web site and participating in outreach (for example, Schoolyard LTER). The research also will involve undergraduates (including the field work if possible) and will support high school interns in the P.I.\u0027s laboratory over the summer.\n", "east": -64.0, "geometry": ["POINT(-71.5 -67)"], "keywords": "Biota; Chemistry:fluid; Chemistry:Fluid; LMG1006; LMG1101; LTER Palmer Station; Oceans; Southern Ocean", "locations": "Southern Ocean", "north": -63.0, "nsf_funding_programs": null, "persons": "Hollibaugh, James T.", "project_titles": "Ammonia Oxidation Versus Heterotrophy in Crenarchaeota Populations from Marine Environments West of the Antarctic Peninsula", "projects": [{"proj_uid": "p0000359", "repository": "USAP-DC", "title": "Ammonia Oxidation Versus Heterotrophy in Crenarchaeota Populations from Marine Environments West of the Antarctic Peninsula"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -71.0, "title": "Ammonia Oxidation Versus Heterotrophy in Crenarchaeota Populations from Marine Environments West of the Antarctic Peninsula", "uid": "600105", "west": -79.0}, {"awards": "0739648 Cary, Stephen", "bounds_geometry": ["POINT(163 -77.5)"], "date_created": "Tue, 01 Jan 2013 00:00:00 GMT", "description": "The glacial streams of the McMurdo Dry Valleys have extensive cyanobacterial mats that are a probable source of fixed C and N to the Valleys. The research will examine the interplay between the microbial mats in the ephemeral glacial streams and the microbiota of the hyporheic soils (wetted soil zone) underlying and adjacent to those mats. It is hypothesized that the mats are important sources of organic carbon and fixed nitrogen for the soil communities of the hyporheic zone, and release dissolved organic carbon (DOC) and nitrogen (DON) that serves the entire Dry Valley ecosystem. Field efforts will entail both observational and experimental components. Direct comparisons will be made between the mats and microbial populations underlying naturally rehydrated and desiccated mat areas, and between mat areas in the melt streams of the Adams and Miers Glaciers in Miers Valley. Both physiological and phylogenetic indices of the soil microbiota will be examined. Observations will include estimates of rates of mat carbon and nitrogen fixation, soil respiration and leucine and thymidine uptake (as measures of protein \u0026 DNA synthesis, respectively) by soil bacteria, bacterial densities and their molecular ecology. Experimental manipulations will include experimental re-wetting of soils and observations of the time course of response of the microbial community. The research will integrate modern molecular genetic approaches (ARISA-DNA fingerprinting and ultra deep 16S rDNA microbial phylogenetic analysis) with geochemistry to study the diversity, ecology, and function of microbial communities that thrive in these extreme environments. The broader impacts of the project include research and educational opportunities for graduate students and a postdoctoral associate. The P.I.s will involve undergraduates as work-study students and in REU programs, and will participate in educational and outreach programs.", "east": 163.0, "geometry": ["POINT(163 -77.5)"], "keywords": "Antarctica; Biota; Cell Counts; Dry Valleys; Microbiology", "locations": "Dry Valleys; Antarctica", "north": -77.5, "nsf_funding_programs": null, "persons": "Cary, S. Craig", "project_titles": "Collaborative Research: Biogeochemistry of Cyanobactrial Mats and Hyporheic Zone Microbes in McMurdo Dry Valley Glacial Meltwater Streams", "projects": [{"proj_uid": "p0000476", "repository": "USAP-DC", "title": "Collaborative Research: Biogeochemistry of Cyanobactrial Mats and Hyporheic Zone Microbes in McMurdo Dry Valley Glacial Meltwater Streams"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.5, "title": "Biogeochemistry of Cyanobactrial Mats and Hyporheic Zone Microbes in McMurdo Dry Valley Glacial Meltwater Streams", "uid": "600079", "west": 163.0}, {"awards": "0440975 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(-119.533333 -80.016667)"], "date_created": "Fri, 17 Jul 2009 00:00:00 GMT", "description": "This data set consists of Gas-isotopic data from the Siple Dome and and Greenland Ice Sheet Project 2 (GISP2) ice cores covering roughly the last 100,000 years (100 ka), consisting of d15N (15N/14N) of N2, d18O (18O/16O) of O2, dO2/N2, and dAr/N2. Derived parameters include d18Oatm, d15N, dO2/N2, and dAr/N2. \n\nData are available via FTP as ASCII text files (.txt) and Microsoft Excel files (.xls).", "east": -119.533333, "geometry": ["POINT(-119.533333 -80.016667)"], "keywords": "Antarctica; Arctic; Atmosphere; Byrd Glacier; Byrd Ice Core; Chemistry:fluid; Chemistry:Fluid; Geochemistry; GISP2; Glaciers/ice Sheet; Glaciers/Ice Sheet; Ice Core Records; Isotope; Paleoclimate; Siple Dome; Siple Dome Ice Core", "locations": "Siple Dome; Byrd Glacier; Arctic; Antarctica", "north": -80.016667, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Nitrogen and oxygen gas isotopes in the Siple Dome and Byrd ice cores", "projects": [{"proj_uid": "p0000450", "repository": "USAP-DC", "title": "Nitrogen and oxygen gas isotopes in the Siple Dome and Byrd ice cores"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": -80.016667, "title": "Nitrogen and Oxygen Gas Isotopes in the Siple Dome and Byrd Ice Cores, Antarctica", "uid": "609407", "west": -119.533333}, {"awards": "0440478 Tang, Kam", "bounds_geometry": ["POINT(166.66267 -77.85067)"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "Phaeocystis Antarctica is a widely distributed phytoplankton that forms dense blooms and aggregates in the Southern Ocean. This phytoplankton and plays important roles in polar ecology and biogeochemistry, in part because it is a dominant primary producer, a main component of organic matter vertical fluxes, and the principal producer of volatile organic sulfur in the region. Yet P. Antarctica is also one of the lesser known species in terms of its physiology, life history and trophic relationships with other organisms; furthermore, information collected on other Phaeocystis species and from different locations may not be applicable to P. Antarctica in the Ross Sea. P. Antarctica occurs mainly as two morphotypes: solitary cells and mucilaginous colonies, which differ significantly in size, architecture and chemical composition. Relative dominance between solitary cells and colonies determines not only the size spectrum of the population, but also its carbon dynamics, nutrient uptake and utilization. Conventional thinking of the planktonic trophic processes is also challenged by the fact that colony formation could effectively alter the predator-prey interactions and interspecific competition. However, the factors that regulate the differences between solitary and colonial forms of P. Antarctica are not well-understood. \n\nThe research objective of this proposal is therefore to address these over-arching questions: \n1. Do P. Antarctica solitary cells and colonies differ in growth, composition and photosynthetic rates? 2. How do nutrients and grazers affect colony development and size distribution of P. Antarctica? \n3. How do nutrients and grazers act synergistically to affect the long-term population dynamics of P. Antarctica? \n\nExperiments will be conducted in the McMurdo station with natural P. Antarctica assemblages and co-occurring grazers. Laboratory experiments will be conducted to study size-specific growth and photosynthetic rates of P. Antarctica, size-specific grazing mortality due to microzooplankton and mesozooplankton, the effects of macronutrients on the (nitrogen compounds) relative dominance of solitary cells and colonies, and the effects of micronutrient (Fe) and grazing related chemical signals on P. Antarctica colony development. Because this species is of critical importance in the Southern Ocean, and because this research will provide critical information on factors that regulate the role of P.Antarctica in food webs and biogeochemical cycles, a major gap in knowledge will be addressed. This project will train two marine science Ph.D. students. The investigators will also collaborate with the School of Education and a marine science museum to communicate polar science to a broader audience.", "east": 166.66267, "geometry": ["POINT(166.66267 -77.85067)"], "keywords": "Biota; Mcmurdo Sound; Oceans; Phytoplankton; Ross Sea; Southern Ocean; Zooplankton", "locations": "Mcmurdo Sound; Ross Sea; Southern Ocean", "north": -77.85067, "nsf_funding_programs": null, "persons": "Smith, Walker; Tang, Kam", "project_titles": "Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial forms of Phaeocystis antarctica", "projects": [{"proj_uid": "p0000214", "repository": "USAP-DC", "title": "Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial forms of Phaeocystis antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.85067, "title": "Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial Forms of Phaeocystis Antarctica", "uid": "600043", "west": 166.66267}, {"awards": "0230276 Ward, Bess", "bounds_geometry": ["POLYGON((162 -77.2,162.16 -77.2,162.32 -77.2,162.48 -77.2,162.64 -77.2,162.8 -77.2,162.96 -77.2,163.12 -77.2,163.28 -77.2,163.44 -77.2,163.6 -77.2,163.6 -77.26,163.6 -77.32,163.6 -77.38,163.6 -77.44,163.6 -77.5,163.6 -77.56,163.6 -77.62,163.6 -77.68,163.6 -77.74,163.6 -77.8,163.44 -77.8,163.28 -77.8,163.12 -77.8,162.96 -77.8,162.8 -77.8,162.64 -77.8,162.48 -77.8,162.32 -77.8,162.16 -77.8,162 -77.8,162 -77.74,162 -77.68,162 -77.62,162 -77.56,162 -77.5,162 -77.44,162 -77.38,162 -77.32,162 -77.26,162 -77.2))"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "Denitrification is the main process by which fixed nitrogen is lost from ecosystems and the regulation of this process may directly affect primary production and carbon cycling over short and long time scales. Previous investigations of the role of bioactive metals in regulating denitrification in bacteria from permanently ice-covered Lake Bonney in the Taylor Valley of East Antarctica indicated that denitrifying bacteria can be negatively affected by metals such as copper, iron, cadmium, lead, chromium, nickel, silver and zinc; and that there is a distinct difference in denitrifying activity between the east and west lobes of the lake. \n\nLow iron concentrations were found to exacerbate the potential toxicity of the other metals, while silver has the potential to specifically inhibit denitrification because of its ability to interfere with copper binding in redox proteins, such as nitrite reductase and nitrous oxide reductase. High silver concentrations might prevent the functioning of nitrous oxide reductase in the same way that simple copper limitation does, thereby causing the buildup of nitrous oxide and resulting in a nonfunctional nitrogen cycle. Other factors, such as oxygen concentration, are likely also to affect bacterial activity in Lake Bonney.\n\nThis project will investigate silver toxicity, general metal toxicity and oxygen concentration to determine their effect on denitrification in the lake by using a suite of \u0027sentinel\u0027 strains of denitrifying bacteria (isolated from the lake) incubated in Lake Bonney water and subjected to various treatments. The physiological responses of these strains to changes in metal and oxygen concentration will be quantified by flow cytometric detection of single cell molecular probes whose sensitivity and interpretation have been optimized for the sentinel strains. Understanding the relationships between metals and denitrification is expected to enhance our understanding of not only Lake Bonney\u0027s unusual nitrogen cycle, but more generally, of the potential role of metals in the regulation of microbial nitrogen transformations. The broader impacts of this work include not only a better understanding of regional biogeochemistry and global perspectives on these processes; but also the training of graduate students and a substantial outreach effort for school children.", "east": 163.6, "geometry": ["POINT(162.8 -77.5)"], "keywords": "Antarctica; Biota; CTD Data; Dry Valleys; Lake Bonney; Lake Vanda; Microbiology; Taylor Valley", "locations": "Dry Valleys; Lake Bonney; Lake Vanda; Taylor Valley; Antarctica", "north": -77.2, "nsf_funding_programs": null, "persons": "Ward, Bess", "project_titles": "Collaborative Research: What Limits Denitrification and Bacterial Growth in Lake Bonney, Taylor Valley, Antarctica?", "projects": [{"proj_uid": "p0000223", "repository": "USAP-DC", "title": "Collaborative Research: What Limits Denitrification and Bacterial Growth in Lake Bonney, Taylor Valley, Antarctica?"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.8, "title": "What Limits Denitrification and Bacterial Growth in Lake Bonney, Taylor Valley, Antarctica?", "uid": "600033", "west": 162.0}, {"awards": "0229638 Ponganis, Paul", "bounds_geometry": ["POLYGON((163 -77,163.4 -77,163.8 -77,164.2 -77,164.6 -77,165 -77,165.4 -77,165.8 -77,166.2 -77,166.6 -77,167 -77,167 -77.1,167 -77.2,167 -77.3,167 -77.4,167 -77.5,167 -77.6,167 -77.7,167 -77.8,167 -77.9,167 -78,166.6 -78,166.2 -78,165.8 -78,165.4 -78,165 -78,164.6 -78,164.2 -78,163.8 -78,163.4 -78,163 -78,163 -77.9,163 -77.8,163 -77.7,163 -77.6,163 -77.5,163 -77.4,163 -77.3,163 -77.2,163 -77.1,163 -77))"], "date_created": "Tue, 01 Jan 2008 00:00:00 GMT", "description": "The emperor penguin, Aptenodytes forsteri, is the premier avian diver and a top predator in the Antarctic ecosystem. The routine occurrence of 500-m diver during foraging trips to sea is both a physiological and behavior enigma. The objectives of this project address how and why emperors dive as deep and long as they do. The project examines four major topics in the diving biology of emperor penguins: pressure tolerance, oxygen store management, end-organ tolerance of diving hypoxemia/ischemia, and deep-dive foraging behavior. These subjects are relevant to the role of the emperor as a top predator in the Antarctic ecosystem, and to critical concepts in diving physiology, including decompression sickness, nitrogen narcosis, shallow water blackout, hypoxemic tolerance, and extension of aerobic dive time. The following hypotheses will be tested: 1) Prevention of nitrogen narcosis and decompression sickness in emperor penguins is achieved by inhibition of pulmonary gas exchange at depth. 2) Shallow water black out does not occur because of greater cerebral hypoxemic tolerance, and, in deep dives, because of resumption of pulmonary gas exchange during final ascent. 3) The rate of depletion of the blood oxygen store is a function of depth of dive and heart rate. 4) The aerobic dive limit (ADL) reflects the onset of lactate accumulation in locomotory muscle, not total depletion of all oxygen stores. 5) Elevation of tissue antioxidant capacity and free-radical scavenging enzyme activities protect against the routine ischemia/reperfusion which occur during diving. 6) During deep dives, the Antarctic silverfish, Pleuorogramma antarcticum, is the primary prey item for emperors. In addition to evaluation of the hypotheses below, the project has broader impacts in several areas such as partnership with foreign and national institutes and organizations (e.g., the National Institute of Polar Research of Japan, Centro de Investigacioines del Noroeste of Mexico, National Geographic, the University of Texas Southwestern Medical Center, and Sea World). Participation in National Geographic television documentaries will provide unique educational opportunities for the general public; development of state-of-the-art technology (e.g., blood oxygen electrode recorders, blood samplers, and miniaturized digital cameras) will lay the groundwork for future research by this group and others; and the effects of the B15 iceberg on breeding success of emperor penguins will continue to be evaluated with population censuses during planned fieldwork at several Ross Sea emperor penguin colonies.", "east": 167.0, "geometry": ["POINT(165 -77.5)"], "keywords": "Antarctica; Biota; Oceans; Penguin; Southern Ocean", "locations": "Antarctica; Southern Ocean", "north": -77.0, "nsf_funding_programs": null, "persons": "Ponganis, Paul", "project_titles": "Diving Physiology and Behavior of Emperor Penguins", "projects": [{"proj_uid": "p0000239", "repository": "USAP-DC", "title": "Diving Physiology and Behavior of Emperor Penguins"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Diving Physiology and Behavior of Emperor Penguins", "uid": "600031", "west": 163.0}, {"awards": "0230260 Bender, Michael", "bounds_geometry": ["POINT(106.8 -72.4667)"], "date_created": "Tue, 10 Jul 2007 00:00:00 GMT", "description": "This data set includes a time scale for the Vostok ice core, retrieved from Vostok Station on the East Antarctic Plateau. This chronology is derived by orbitally tuning to molecular oxygen to nitrogen (O\u003csub\u003e2\u003c/sub\u003e/N\u003csub\u003e2\u003c/sub\u003e) ratios in occluded air for depths deeper than 1550 m (greater than 112,000 years old), and by gas correlation to the Greenland Ice Sheet Project 2 (GISP2) chronology for the ice core section that is shallower than 1422 m (less than 102,000 years old). Because of poor gas preservation in air bubbles in shallower depths, investigators could only constrain the Vostok chronology for the section deeper than 1550 m by O\u003csub\u003e2\u003c/sub\u003e/N\u003csub\u003e2\u003c/sub\u003e. Thus for the shallower section of the core, they synchronized the Vostok delta oxygen-18 (\u0026delta;\u003csup\u003e18\u003c/sup\u003eO) and methane (CH\u003csub\u003e4\u003c/sub\u003e) measurements to those of the GISP2 to obtain the chronology (see Bender, et al. 2006). Note, CH\u003csub\u003e4\u003c/sub\u003e data are not included in this data set.\n\nInvestigators analyzed the O\u003csub\u003e2\u003c/sub\u003e/N\u003csub\u003e2\u003c/sub\u003e and the\u003cem\u003e\u003cstrong\u003e \u003c/strong\u003e\u003c/em\u003e\u0026delta;\u003csup\u003e18\u003c/sup\u003eO record ratios for approximately the past 115,000 to 400,000 years in the Vostok ice core. They combined new measurements for O\u003csub\u003e2\u003c/sub\u003e/N\u003csub\u003e2\u003c/sub\u003e and \u0026delta;\u003csup\u003e18\u003c/sup\u003eO with data from Bender (2002) and Petit, et al. (1999), respectively.\n\nData are in Microsoft Excel format and are available via FTP.", "east": 106.8, "geometry": ["POINT(106.8 -72.4667)"], "keywords": "Antarctica; Atmosphere; Chemistry:fluid; Chemistry:Fluid; Geochronology; Glaciers/ice Sheet; Glaciers/Ice Sheet; Ice Core Records; Lake Vostok; Paleoclimate; Vostok; Vostok Ice Core", "locations": "Lake Vostok; Vostok; Antarctica", "north": -72.4667, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Bender, Michael; Suwa, Makoto", "project_titles": "Collaborative Research: Trapped Gas Composition and the Chronology of the Vostok Ice Core", "projects": [{"proj_uid": "p0000257", "repository": "USAP-DC", "title": "Collaborative Research: Trapped Gas Composition and the Chronology of the Vostok Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -72.4667, "title": "Trapped Gas Composition and Chronology of the Vostok Ice Core", "uid": "609311", "west": 106.8}]

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