USAP-DC

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

[{"awards": "1744871 Robinson, Rebecca", "bounds_geometry": ["POLYGON((100 -62,104.4 -62,108.8 -62,113.2 -62,117.6 -62,122 -62,126.4 -62,130.8 -62,135.2 -62,139.6 -62,144 -62,144 -64,144 -66,144 -68,144 -70,144 -72,144 -74,144 -76,144 -78,144 -80,144 -82,139.6 -82,135.2 -82,130.8 -82,126.4 -82,122 -82,117.6 -82,113.19999999999999 -82,108.8 -82,104.4 -82,100 -82,100 -80,100 -78,100 -76,100 -74,100 -72,100 -70,100 -68,100 -66,100 -64,100 -62))"], "date_created": "Tue, 13 Aug 2024 00:00:00 GMT", "description": "This dataset includes measurements of diatom-bound nitrogen isotopic composition (d15Ndb; \u2030 vs air), bulk sedimentary nitrogen isotopic composition (d15Nbulk; \u2030 vs air), and total nitrogen (wt%) from 121 samples from IODP Site U1357B in the Adelie Basin. The sediments are Holocene age (11 kyBP to present).", "east": 144.0, "geometry": ["POINT(122 -72)"], "keywords": "Antarctica; Cryosphere; Wilkes Land", "locations": "Antarctica; Wilkes Land", "north": -62.0, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dove, Isabel; Kelly, Roger; Robinson, Rebecca", "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": -82.0, "title": "Diatom-bound and bulk sedimentary nitrogen isotopes from IODP Site U1357", "uid": "601817", "west": 100.0}, {"awards": "1745064 Perez-Huerta, Alberto; 1745080 Gillikin, David; 1745057 Walker, Sally; 0739512 Walker, Sally", "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": "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"}, {"proj_uid": "p0000203", "repository": "USAP-DC", "title": "Collaborative Research: Linking Modern Benthic Communities and Taphonomic Processes to the Stratigraphic Record of Antarctic Cores"}], "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": "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; WAIS; Antarctica", "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": "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": "Antarctica; Antarctic Peninsula", "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": "1903681 Brook, Edward J.", "bounds_geometry": ["POLYGON((161.745 -77.745,161.746 -77.745,161.747 -77.745,161.748 -77.745,161.749 -77.745,161.75 -77.745,161.751 -77.745,161.752 -77.745,161.753 -77.745,161.754 -77.745,161.755 -77.745,161.755 -77.74600000000001,161.755 -77.747,161.755 -77.748,161.755 -77.749,161.755 -77.75,161.755 -77.751,161.755 -77.752,161.755 -77.753,161.755 -77.75399999999999,161.755 -77.755,161.754 -77.755,161.753 -77.755,161.752 -77.755,161.751 -77.755,161.75 -77.755,161.749 -77.755,161.748 -77.755,161.747 -77.755,161.746 -77.755,161.745 -77.755,161.745 -77.75399999999999,161.745 -77.753,161.745 -77.752,161.745 -77.751,161.745 -77.75,161.745 -77.749,161.745 -77.748,161.745 -77.747,161.745 -77.74600000000001,161.745 -77.745))"], "date_created": "Tue, 02 Aug 2022 00:00:00 GMT", "description": "Measurements of the isotopic composition of atmospheric nitrous oxide from samples from the Taylor Glacier, Antarctica, spanning the last deglaciation (21-11 ka) and part of the last glacial period (40 to 36 ka). Data set includes the site preference of 15-N in N2O. A manuscript describing these data is currently in preparation. Data are referenced to in house air standards at OSU which are currently being cross calibrated with other laboratories. ", "east": 161.755, "geometry": ["POINT(161.75 -77.75)"], "keywords": "Antarctica; Nitrous Oxide; Taylor Glacier", "locations": "Taylor Glacier; Antarctica", "north": -77.745, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Menking, Andy; Brook, Edward J.", "project_titles": "Deciphering Changes in Atmospheric Nitrous Oxide Concentration During the Last Ice Age Using the Intramolecular Site-Preference of Nitrogen Isotopes", "projects": [{"proj_uid": "p0010465", "repository": "USAP-DC", "title": "Deciphering Changes in Atmospheric Nitrous Oxide Concentration During the Last Ice Age Using the Intramolecular Site-Preference of Nitrogen Isotopes"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.755, "title": "Preliminary nitrous oxide site preference isotopic data for last deglaciation from Taylor Glacier", "uid": "601592", "west": 161.745}, {"awards": "1341432 Brzezinski, Mark; 1341464 Robinson, Rebecca", "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": "Antarctica; Antarctica; South Pole; South Pole", "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": "1341432 Brzezinski, Mark; 1341464 Robinson, Rebecca", "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": "Antarctica; Southern Ocean", "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": "1826712 McMahon, Kelton; 1443585 Polito, Michael; 1443424 McMahon, Kelton; 1443386 Emslie, Steven", "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": "Antarctica; Antarctica; Southern Ocean; Antarctic Peninsula", "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; 1443424 McMahon, Kelton; 1826712 McMahon, Kelton; 1443386 Emslie, Steven", "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": "Southern Ocean; Antarctic Peninsula; 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 J.; 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": "Antarctica; Taylor Dome", "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": "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; Antarctica; South Pole", "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": "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}]

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