USAP-DC

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

[{"awards": "1143836 Leventer, Amy", "bounds_geometry": ["POLYGON((117 -66,119.9 -66,122.8 -66,125.7 -66,128.6 -66,131.5 -66,134.4 -66,137.3 -66,140.2 -66,143.1 -66,146 -66,146 -66.1,146 -66.2,146 -66.3,146 -66.4,146 -66.5,146 -66.6,146 -66.7,146 -66.8,146 -66.9,146 -67,143.1 -67,140.2 -67,137.3 -67,134.4 -67,131.5 -67,128.6 -67,125.7 -67,122.8 -67,119.9 -67,117 -67,117 -66.9,117 -66.8,117 -66.7,117 -66.6,117 -66.5,117 -66.4,117 -66.3,117 -66.2,117 -66.1,117 -66))"], "date_created": "Mon, 21 Oct 2024 00:00:00 GMT", "description": "Totten Glacier is the termination of the largest marine-based portion of the East Antarctic Ice Sheet, the Aurora Subglacial Basin. Yet little is known about the glacial evolution of the catchment and the factors influencing its present and past behavior. Due its remote location and heavy sea ice, the continental shelf in front of the Totten Glacier had not been comprehensively surveyed prior to this study. Satellite observations indicate that the Totten ice drainage system is thinning, and it has been hypothesized that this thinning is in response to undermelting by warm ocean waters over the continental shelf. While this process is observed elsewhere in Antarctica (e.g. the rapidly retreating Pine Island Glacier in West Antarctica), the Totten Glacier system is potentially Antarcticas most important glacial drainage system due to its large size; it is three times larger than any system in West Antarctica. \u003c/br\u003eThe main goals of this proposal were: \u003c/br\u003eTo generate multibeam bathymetric maps of the continental shelf proximal to the Totten Glacier system to understand the recent regional glacial history and to document the pathways, if any, for circumpolar deep water to move onto the shelf. \u003c/br\u003eTo conduct a physical oceanographic survey of the region proximal to the Totten Glacier system, to determine the presence, if any, of warm ocean waters over the continental shelf.\u003c/br\u003eTo conduct a seismic survey of the continental shelf to assess the long-term evolution of the glacial system in the Aurora Subglacial Basin.\u003c/br\u003eTo collect marine sediment cores to determine the regional deglacial to Holocene climate history and the influence of warm circumpolar deep water.", "east": 146.0, "geometry": ["POINT(131.5 -66.5)"], "keywords": "Antarctica; Cryosphere; Diatom; NBP1402; Totten Glacier", "locations": "Totten Glacier; Antarctica; Antarctica", "north": -66.0, "nsf_funding_programs": "Antarctic Integrated System Science", "persons": "Leventer, Amy; NBP1402 science party, ", "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": -67.0, "title": "NBP1402 diatom data", "uid": "601845", "west": 117.0}, {"awards": "1939146 Siddoway, Christine", "bounds_geometry": ["POLYGON((-109.1 -68.6,-108.94 -68.6,-108.78 -68.6,-108.61999999999999 -68.6,-108.46 -68.6,-108.3 -68.6,-108.14 -68.6,-107.98 -68.6,-107.82 -68.6,-107.66 -68.6,-107.5 -68.6,-107.5 -68.64,-107.5 -68.67999999999999,-107.5 -68.72,-107.5 -68.75999999999999,-107.5 -68.8,-107.5 -68.84,-107.5 -68.88,-107.5 -68.92,-107.5 -68.96,-107.5 -69,-107.66 -69,-107.82 -69,-107.98 -69,-108.14 -69,-108.3 -69,-108.46 -69,-108.61999999999999 -69,-108.78 -69,-108.94 -69,-109.1 -69,-109.1 -68.96,-109.1 -68.92,-109.1 -68.88,-109.1 -68.84,-109.1 -68.8,-109.1 -68.75999999999999,-109.1 -68.72,-109.1 -68.67999999999999,-109.1 -68.64,-109.1 -68.6))"], "date_created": "Tue, 27 Aug 2024 00:00:00 GMT", "description": "The table contains sample identifiers, location data, and geochronology data (U-Pb zircon dates; apatite fission track determinations) from selected intervals of sediment cores obtained at sites U1532 (A, B, C, G) and U1533 (A, B) recovered during IODP Expedition 379 to the outer Amundsen Sea, Antarctica.", "east": -107.5, "geometry": ["POINT(-108.3 -68.8)"], "keywords": "Amundsen Sea; Antarctica; Cryosphere; Geochronology; Marie Byrd Land; Subglacial Bedrock; Thermochronology", "locations": "Marie Byrd Land; Amundsen Sea; Antarctica; Amundsen Sea", "north": -68.6, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Siddoway, Christine", "project_titles": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica", "projects": [{"proj_uid": "p0010451", "repository": "USAP-DC", "title": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.0, "title": "U-Pb zircon and apatite fission track dates for IRD (ice-rafted cobbles and mineral grains) from IODP379 drill sites", "uid": "601828", "west": -109.1}, {"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": "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 quantitative diatom assemblage data from 60 samples from IODP Site U1357B on the Adelie Basin. The record spans from 11,000 yBP to present.", "east": 144.0, "geometry": ["POINT(122 -72)"], "keywords": "Antarctica; Cryosphere; Geochemistry; Sediment; Wilkes Land", "locations": "Wilkes Land; Antarctica", "north": -62.0, "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": -82.0, "title": "Diatom assemblage from IODP Site U1357", "uid": "601818", "west": 100.0}, {"awards": "1744871 Robinson, Rebecca", "bounds_geometry": ["POLYGON((-80 -59,-76.8 -59,-73.6 -59,-70.4 -59,-67.2 -59,-64 -59,-60.8 -59,-57.599999999999994 -59,-54.4 -59,-51.2 -59,-48 -59,-48 -60.6,-48 -62.2,-48 -63.8,-48 -65.4,-48 -67,-48 -68.6,-48 -70.2,-48 -71.8,-48 -73.4,-48 -75,-51.2 -75,-54.4 -75,-57.6 -75,-60.8 -75,-64 -75,-67.2 -75,-70.4 -75,-73.6 -75,-76.8 -75,-80 -75,-80 -73.4,-80 -71.8,-80 -70.2,-80 -68.6,-80 -67,-80 -65.4,-80 -63.8,-80 -62.2,-80 -60.6,-80 -59))"], "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 81 Holocene and late deglacial-aged samples from ODP Site 1098B on the western Antarctic Peninsula.", "east": -48.0, "geometry": ["POINT(-64 -67)"], "keywords": "Antarctica; Antarctic Peninsula; Cryosphere; Geochemistry; Sediment", "locations": "Antarctic Peninsula; Antarctica", "north": -59.0, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dove, Isabel; Jones, Colin; 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": -75.0, "title": "Diatom-bound and bulk sedimentary N isotopes from ODP Site 1098, Western Antarctic Peninsula", "uid": "601816", "west": -80.0}, {"awards": "1939139 Scherer, Reed", "bounds_geometry": null, "date_created": "Thu, 27 Jun 2024 00:00:00 GMT", "description": "This dataset contains physical measurements of specimens of the Southern Ocean diatom Fragilariopsis kerguelensis. We used the image segmentation software SHERPA (Kloster et al., 2017) to make physical measurements of each valve including \"rectangularity\". F. kerguelensis rectangularity has been posited to change in response to Sea Surface Temperature, a relationship that we explore in this study by calculating SSTs using established and new valve rectangularity/SST calibrations. ", "east": null, "geometry": null, "keywords": "Amundsen Sea; Antarctica; Cryosphere; Oceanography; Sabrina Coast; Sea Surface Temperature; Southern Ocean", "locations": "Sabrina Coast; Amundsen Sea; Antarctica; Southern Ocean; Amundsen Sea; Sabrina Coast; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Ruggiero, Joseph", "project_titles": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica", "projects": [{"proj_uid": "p0010451", "repository": "USAP-DC", "title": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Population morphometrics of the Southern Ocean diatom Fragilariopsis kerguelensis related to Sea Surface Temperature", "uid": "601804", "west": null}, {"awards": "1744871 Robinson, Rebecca", "bounds_geometry": ["POINT(-64.207 -64.86)"], "date_created": "Wed, 24 Apr 2024 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; Cryosphere", "locations": "Antarctic Peninsula; 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": "601778", "west": -64.207}, {"awards": "1744871 Robinson, Rebecca", "bounds_geometry": ["POINT(-64 -65)"], "date_created": "Wed, 24 Apr 2024 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 12 samples.", "east": -64.0, "geometry": ["POINT(-64 -65)"], "keywords": "Antarctica; Antarctic Peninsula; Cryosphere; Sediment Core Data", "locations": "Antarctic Peninsula; Antarctica", "north": -65.0, "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": -65.0, "title": "ODP Site 1098 deglacial diatom assemblage", "uid": "601777", "west": -64.0}, {"awards": "1939139 Scherer, Reed", "bounds_geometry": null, "date_created": "Tue, 20 Feb 2024 00:00:00 GMT", "description": "", "east": null, "geometry": null, "keywords": "Antarctica; Biogenic Silica; Diatom", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Scherer, Reed Paul; Furlong, Heather", "project_titles": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica", "projects": [{"proj_uid": "p0010451", "repository": "USAP-DC", "title": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Pliocene diatom abundance, IODP 379-U1532", "uid": "601769", "west": null}, {"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": "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": "1543245 Rynearson, Tatiana", "bounds_geometry": ["POLYGON((-179 -59,-167.7 -59,-156.4 -59,-145.1 -59,-133.8 -59,-122.5 -59,-111.19999999999999 -59,-99.89999999999999 -59,-88.6 -59,-77.3 -59,-66 -59,-66 -60.9,-66 -62.8,-66 -64.7,-66 -66.6,-66 -68.5,-66 -70.4,-66 -72.3,-66 -74.2,-66 -76.1,-66 -78,-77.3 -78,-88.6 -78,-99.9 -78,-111.2 -78,-122.5 -78,-133.8 -78,-145.10000000000002 -78,-156.4 -78,-167.7 -78,-179 -78,-179 -76.1,-179 -74.2,-179 -72.3,-179 -70.4,-179 -68.5,-179 -66.6,-179 -64.7,-179 -62.8,-179 -60.900000000000006,-179 -59))"], "date_created": "Mon, 27 Jun 2022 00:00:00 GMT", "description": "This dataset includes records of the specific growth rates measured for 43 clonal diatom strains originally isolated during the research cruise NBP-1701 across the Pacific sector of the Southern Ocean during December 2016-January 2017. Strains were grown under continuous light (130 \u00b5mol m-2\u00a0s-1) at up to 8 temperatures that span all or most of each strain\u2019s thermal niche width, from 0-12 degrees C, which encompasses each strain\u2019s optimum temperature for growth. Strains have been molecularly identified to species via 18S Sanger sequencing. Data include the following information for each record: Internal lab strain reference ID, date collected, latitude, longitude, Southern Ocean region, species, tested temperature, replicate number and specific growth rate. Data are provided in comma-separated values (csv) format.", "east": -66.0, "geometry": ["POINT(-122.5 -68.5)"], "keywords": "Antarctica; Biota; NBP1701; Phytoplankton; R/v Nathaniel B. Palmer; Specific Growth Rate; Thermal Optimum Temperature", "locations": "Antarctica", "north": -59.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "persons": "Bishop, Ian", "project_titles": "NSFGEO-NERC: Evolutionary Response of Southern Ocean Diatoms to Environmental Change", "projects": [{"proj_uid": "p0000850", "repository": "USAP-DC", "title": "NSFGEO-NERC: Evolutionary Response of Southern Ocean Diatoms to Environmental Change"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Specific growth rate measurements for 43 Southern Ocean diatoms", "uid": "601586", "west": -179.0}, {"awards": "1743643 Passchier, Sandra", "bounds_geometry": ["POINT(-42.933 -61.849)"], "date_created": "Tue, 21 Jun 2022 00:00:00 GMT", "description": "This dataset contains measurements of terrigenous particle-size distributions on Eocene-Oligocene sediment from Ocean Drilling Program Site 696 drilled in 650 m water depth on the South Orkney Microcontinent. Carbonate and organic matter were removed through addition of 10mL aliquots of 30% H2O2, 2mL aliquots of 10% HCl to ~50-100mL suspension on a hot plate. Diatoms were generally either absent or present in trace amounts in the Eocene-Oligocene interval and were not removed. Dispersion was through heating with sodium pyrophosphate. Samples were measured on a Malvern Mastersizer 2000 with a Hydro 2000MU (A) accessory, using a Refractive Index of 1.6 (Illite) and an absorption coefficient of 0.9. Results are in (vol. %) per size class, with diameter range equivalent to the diameter of spheres with the same volume as measured particles.", "east": -42.933, "geometry": ["POINT(-42.933 -61.849)"], "keywords": "Antarctica; Glaciation; IODP 696; Marine Geoscience; Marine Sediments; Paleoceanography; Sediment Core Data; Weddell Sea", "locations": "Weddell Sea; Antarctica", "north": -61.849, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Passchier, Sandra; Lepp, Allison; Horowitz Castaldo, Josie; Light, Jennifer", "project_titles": "Timing and Spatial Distribution of Antarctic Ice Sheet Growth and Sea-ice Formation across the Eocene-Oligocene Transition", "projects": [{"proj_uid": "p0010101", "repository": "USAP-DC", "title": "Timing and Spatial Distribution of Antarctic Ice Sheet Growth and Sea-ice Formation across the Eocene-Oligocene Transition"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -61.849, "title": "Particle-size distributions of Eocene-Oligocene sediment from ODP Site 696, South Orkney Microcontinent", "uid": "601581", "west": -42.933}, {"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": "Antarctica; Southern Ocean; Southern Ocean", "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": "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": "Mon, 16 May 2022 00:00:00 GMT", "description": "This dataset contains data for stable isotopes of silicon in pore water, interstitial water, sediments and CTD profiles.", "east": -165.0, "geometry": ["POINT(-170 -60.5)"], "keywords": "Antarctica; Biogenic Silica; Chemistry:sediment; Chemistry:Sediment; Lithogenic Silica; Marine Geoscience; NBP1702; Pore Water Biogeochemistry; Sediment; Silicon Cycle; Silicon Stable Isotope; Southern Ocean", "locations": "Antarctica; Southern Ocean", "north": -54.0, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Closset, Ivia; Jones, Janice L.; 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": "Silicon concentration and isotopic composition measurements in seawater profiles, pore waters, interstitial waters and sediments from 67\u00b0S to 55\u00b0S latitude in the Pacific Sector of the Southern Ocean", "uid": "601562", "west": -175.0}, {"awards": "1744760 Hopkinson, Brian; 1745036 Marchetti, Adrian", "bounds_geometry": null, "date_created": "Sat, 05 Mar 2022 00:00:00 GMT", "description": "This dataset contains measurements of photosynthetic physiological traits of various species of Southern Ocean marine diatoms when grown under differing levels of iron availability ", "east": null, "geometry": null, "keywords": "Antarctica; Diatom", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Organisms and Ecosystems", "persons": "Hopkinson, Brian; Plumb, Kaylie; Marchetti, Adrian; Andrew, Sarah", "project_titles": "Collaborative research: Antarctic diatom proteorhodopsins: Characterization and a potential role in the iron-limitation response", "projects": [{"proj_uid": "p0010033", "repository": "USAP-DC", "title": "Collaborative research: Antarctic diatom proteorhodopsins: Characterization and a potential role in the iron-limitation response"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Photosynthetic physiological data of Proteorhodopsin containing diatoms under differing iron availabilities", "uid": "601530", "west": null}, {"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": "Community composition data, generated in support of a field-based experimental investigation of the role of diatom assemblages in setting the isotopic composition of diatom bound N, show significant assemblage differences between ~66S and ~61S in the Southern Ocean during the late summer.", "east": -170.0, "geometry": ["POINT(-170.2 -63.5)"], "keywords": "Antarctica; Biota; Carboy Growouts; Diatom; Diatom Assemblage Data; NBP1702; Oceans; R/v Nathaniel B. Palmer; Southern Ocean; Southern Ocean Summer", "locations": "Southern Ocean; Antarctica", "north": -60.8, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Jones, Colin; Robinson, Rebecca; Riesselman, Christina; 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": "Diatom assemblage counts from NBP17-02 shipboard carboy experiments", "uid": "601523", "west": -170.4}, {"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": "1433140 Domack, Eugene; 0732625 Leventer, Amy", "bounds_geometry": ["POLYGON((-69 -58,-67.7 -58,-66.4 -58,-65.1 -58,-63.8 -58,-62.5 -58,-61.2 -58,-59.9 -58,-58.6 -58,-57.3 -58,-56 -58,-56 -59,-56 -60,-56 -61,-56 -62,-56 -63,-56 -64,-56 -65,-56 -66,-56 -67,-56 -68,-57.3 -68,-58.6 -68,-59.9 -68,-61.2 -68,-62.5 -68,-63.8 -68,-65.1 -68,-66.4 -68,-67.7 -68,-69 -68,-69 -67,-69 -66,-69 -65,-69 -64,-69 -63,-69 -62,-69 -61,-69 -60,-69 -59,-69 -58))"], "date_created": "Mon, 15 Nov 2021 00:00:00 GMT", "description": "This data set contains an age vs depth model and measurements of magnetic susceptibility, benthic foraminifera Bulimina aculeata d18O and d13C, bulk sediment GDGT data, and diatom assemblage data from USAP LMG13-11 JKC-1 sediment core (0-100 cm) archived at the Oregon State University ACC repository. All stable isotope and GDGT measurements were made at the University of South Florida College of Marine Science. Diatom assemblages were counted at Colgate University. The data set includes all replicate measurements. Details of the entire data set and all relevant methods are provided in Browne et al (submitted, 2021)", "east": -56.0, "geometry": ["POINT(-62.5 -63)"], "keywords": "Antarctica; Antarctic Peninsula; Delta 13C; Delta 18O; Paleoceanography; Temperature", "locations": "Antarctic Peninsula; Antarctica", "north": -58.0, "nsf_funding_programs": "Antarctic Integrated System Science; Antarctic Integrated System Science", "persons": "Shevenell, Amelia", "project_titles": "Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, a Multidisciplinary Approach -- Cryosphere and Oceans", "projects": [{"proj_uid": "p0000101", "repository": "USAP-DC", "title": "Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, a Multidisciplinary Approach -- Cryosphere and Oceans"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "LARISSA", "south": -68.0, "title": "LMG13-11 JKC-1 Paleoceanographic data", "uid": "601485", "west": -69.0}, {"awards": "1143836 Leventer, Amy", "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 -66.1,121 -66.2,121 -66.3,121 -66.4,121 -66.5,121 -66.6,121 -66.7,121 -66.8,121 -66.9,121 -67,120.9 -67,120.8 -67,120.7 -67,120.6 -67,120.5 -67,120.4 -67,120.3 -67,120.2 -67,120.1 -67,120 -67,120 -66.9,120 -66.8,120 -66.7,120 -66.6,120 -66.5,120 -66.4,120 -66.3,120 -66.2,120 -66.1,120 -66))"], "date_created": "Tue, 27 Apr 2021 00:00:00 GMT", "description": "This dataset includes diatom data, both absolute abundance and relative contribution, for NBP1402 JPC43. ", "east": 121.0, "geometry": ["POINT(120.5 -66.5)"], "keywords": "Antarctica; Diatom; Holocene; Jumbo Piston Corer; NBP1402; R/v Nathaniel B. Palmer; Sabrina Coast; Sediment Core Data; Species Abundance; Totten Glacier", "locations": "Sabrina Coast; Antarctica; Totten Glacier", "north": -66.0, "nsf_funding_programs": "Antarctic Integrated System Science", "persons": "Leventer, Amy", "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": -67.0, "title": "NBP1402 JPC43 Diatom Data", "uid": "601440", "west": 120.0}, {"awards": "9909367 Leventer, Amy", "bounds_geometry": ["POINT(62.99 -67.13)"], "date_created": "Fri, 01 May 2020 00:00:00 GMT", "description": "This data set was acquired with a Jumbo Piston Core Sediment Sampler during R/V Nathaniel B. Palmer expedition NBP0101 conducted in 2001. This data file is of Microsoft Excel format and includes Quantitative Diatom Assemblage data; counts completed on randomly settled slides (Scherer, R.P., 1994. A new method for the determination of absolute abundance of diatoms and other silt-sized sedimentary particles. Journal of Paleolimnology, 12 (1), 171-178, doi:10.1007/BF00678093). These counts were completed at closely spaced intervals in NBP0101 JPC41, a jumbo piston core from Iceberg Alley, Mac.Robertson Shelf, East Antarctica", "east": 62.99, "geometry": ["POINT(62.99 -67.13)"], "keywords": "Antarctica; Biota; Diatom; East Antarctica; Mac. Robertson Shelf; Marine Geoscience; Microscope; NBP0101; Paleoclimate; Piston Corer; R/v Nathaniel B. Palmer; Sediment Core; Species Abundance", "locations": "East Antarctica; Mac. Robertson Shelf; Antarctica; Mac. Robertson Shelf", "north": -67.13, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Leventer, Amy", "project_titles": "Quaternary Glacial History and Paleoenvironments of the East Antarctic Margin", "projects": [{"proj_uid": "p0000609", "repository": "USAP-DC", "title": "Quaternary Glacial History and Paleoenvironments of the East Antarctic Margin"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -67.13, "title": "Quantitative Diatom Assemblage Data from Iceberg Alley, Mac. Robertson Shelf, East Antarctica acquired during expedition NBP0101", "uid": "601307", "west": 62.99}, {"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": "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": "Tue, 31 Mar 2020 00:00:00 GMT", "description": "This dataset contains the water column profiles of dissolved nutrients, NO3, PO4, dissolved Si, biogenic Si, lithogenic Si, chlorophyll and phaeophytin concentrations, and the d15NO3.", "east": -165.0, "geometry": ["POINT(-170 -60.5)"], "keywords": "Antarctica; Chlorophyll; 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": "Dissolved nutrient profiles from along 170\u00b0W between 67 and 54\u00b0S", "uid": "601269", "west": -175.0}, {"awards": "1443420 Dodd, Justin", "bounds_geometry": ["POINT(167.083333 -77.888889)"], "date_created": "Sun, 27 Oct 2019 00:00:00 GMT", "description": "The Andrill-1B (AND-1B) sediment core from under the Ross Ice Shelf in McMurdo Sound, Antarctica, recovered a mid to late Pliocene (~4.68 to 3.44 Ma) age diatomite unit with d18Odiatom values that range from +32.6 to +37.6 \u2030 (n=50 ", "east": 167.083333, "geometry": ["POINT(167.083333 -77.888889)"], "keywords": "And-1B; Andrill; Antarctica; Chemistry:sediment; Chemistry:Sediment; Delta 18O; Diatom; Mass Spectrometer; Oxygen Isotope; Paleoclimate; Pliocene; Sediment; Wais Project; West Antarctic Ice Sheet", "locations": "West Antarctic Ice Sheet; Antarctica", "north": -77.888889, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dodd, Justin; Abbott, Tirzah", "project_titles": "Diatom and Oxygen Isotope Evidence of Pliocene Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography", "projects": [{"proj_uid": "p0010042", "repository": "USAP-DC", "title": "Diatom and Oxygen Isotope Evidence of Pliocene Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "ANDRILL", "south": -77.888889, "title": "Diatom Oxygen Isotope Evidence of Pliocene (~4.68 to 3.44 Ma) Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography", "uid": "601220", "west": 167.083333}, {"awards": "0732625 Leventer, Amy; 9714371 Leventer, Amy", "bounds_geometry": ["POLYGON((-64 -63,-63.1 -63,-62.2 -63,-61.3 -63,-60.4 -63,-59.5 -63,-58.6 -63,-57.7 -63,-56.8 -63,-55.9 -63,-55 -63,-55 -63.4,-55 -63.8,-55 -64.2,-55 -64.6,-55 -65,-55 -65.4,-55 -65.8,-55 -66.2,-55 -66.6,-55 -67,-55.9 -67,-56.8 -67,-57.7 -67,-58.6 -67,-59.5 -67,-60.4 -67,-61.3 -67,-62.2 -67,-63.1 -67,-64 -67,-64 -66.6,-64 -66.2,-64 -65.8,-64 -65.4,-64 -65,-64 -64.6,-64 -64.2,-64 -63.8,-64 -63.4,-64 -63))"], "date_created": "Mon, 16 Sep 2019 00:00:00 GMT", "description": "Diatom data from eastern side of Antarctic Peninsula:\r\n\r\nThis file includes quantitative diatom data for surface samples collected on numerous cruises to the eastern side of the Antarctic Peninsula, including NBP0003, NBP0107, LMG0502, NBP0603, and NBP1203. Samples were collected using a variety of tools including Smith-McIntyre Grab, Kasten Core and Jumbo Kasten Core. These data were generated by Amy Leventer (aleventer@colgate.edu) and undergraduate students at Colgate University. All questions regarding the specifics of these data should be directed to Amy Leventer. \r\n\r\nQuantitative diatom slides were prepared according to the settling technique of Scherer (1995). Cover slips were adhered to the slides using Norland Optical Adhesive #61. Slides were observed under Olympus CX31, BX50 and BX60, and Zeiss Primo Star light microscopes, using a 100X oil immersion objective for a total magnification of 1000X. A minimum of 400 valves or 10 transects was counted for each slide, depending on the absolute diatom abundance. Valves were only counted if \u003e50% complete. Diatoms were identified to species level when possible (Crosta et al., 2005; Armand et al., 2005; Cefarelli et al., 2010).\r\n\r\nArmand, L.K., X. Crosta, O. Romero, J. J. Pichon (2005), The biogeography of major diatom taxa in Southern Ocean sediments: 1. Sea ice related species, Paleogeography, Paleoclimatology, Paleoecology, 223, 93-126. \r\n\r\nCefarelli, A.O., M. E. Ferrario, G. O. Almandoz, A. G. Atencio, R. Akselman, M. Vernet (2010), Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance, Polar Biology, 33(2), 1463-1484. \r\n\r\nCrosta, X., O. Romero, L. K. Armand, J. Pichon (2005), The biogeography of major diatom taxa in Southern Ocean sediments: 2. Open ocean related species, Palaeogeography, Palaeoclimatology, Palaeoecology, 223, 66-92. \r\n\r\nScherer, R. P., A new method for the determination of absolute abundance of diatoms and other silt-sized sedimentary particles, J. Paleolimnol., 12, 171\u2013178, 1995.\r\n", "east": -55.0, "geometry": ["POINT(-59.5 -65)"], "keywords": "Antarctica; Antarctic Peninsula; Benthos; Biota; Diatom; Geology/Geophysics - Other; LMG0502; Marine Geoscience; Marine Sediments; Microscope; NBP0003; NBP0107; NBP0603; NBP1203; R/v Nathaniel B. Palmer; Surface Sediment", "locations": "Antarctica; Antarctic Peninsula", "north": -63.0, "nsf_funding_programs": "Antarctic Integrated System Science; Antarctic Ocean and Atmospheric Sciences", "persons": "Leventer, Amy", "project_titles": "Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, a Multidisciplinary Approach -- Cryosphere and Oceans", "projects": [{"proj_uid": "p0000101", "repository": "USAP-DC", "title": "Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, a Multidisciplinary Approach -- Cryosphere and Oceans"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "LARISSA", "south": -67.0, "title": "Easten Antarctic Peninsula Surface Sediment Diatom Data", "uid": "601211", "west": -64.0}, {"awards": "9909367 Leventer, Amy", "bounds_geometry": ["POLYGON((57 -66,57.3 -66,57.6 -66,57.9 -66,58.2 -66,58.5 -66,58.8 -66,59.1 -66,59.4 -66,59.7 -66,60 -66,60 -66.1,60 -66.2,60 -66.3,60 -66.4,60 -66.5,60 -66.6,60 -66.7,60 -66.8,60 -66.9,60 -67,59.7 -67,59.4 -67,59.1 -67,58.8 -67,58.5 -67,58.2 -67,57.9 -67,57.6 -67,57.3 -67,57 -67,57 -66.9,57 -66.8,57 -66.7,57 -66.6,57 -66.5,57 -66.4,57 -66.3,57 -66.2,57 -66.1,57 -66))"], "date_created": "Thu, 25 Apr 2019 00:00:00 GMT", "description": "This data set describes diatom assemblages and abundances from two sediment cores retrieved from Edward VIII Gulf. The assemblages are used to reconstruct paleoceanographic conditions throughout the Holocene.", "east": 60.0, "geometry": ["POINT(58.5 -66.5)"], "keywords": "Antarctica; Biota; Diatom; East Antarctica; Microscopy; NBP0101; Oceans; Paleoceanography; Paleoclimate; R/v Nathaniel B. Palmer; Sediment Corer", "locations": "East Antarctica; Antarctica", "north": -66.0, "nsf_funding_programs": "Antarctic Integrated System Science", "persons": "Leventer, Amy", "project_titles": "Quaternary Glacial History and Paleoenvironments of the East Antarctic Margin", "projects": [{"proj_uid": "p0000609", "repository": "USAP-DC", "title": "Quaternary Glacial History and Paleoenvironments of the East Antarctic Margin"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -67.0, "title": "Diatom assemblages from Edward VIII Gulf, Kemp Coast, East Antarctica", "uid": "601177", "west": 57.0}, {"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": "0839059 Powell, Ross", "bounds_geometry": ["POLYGON((-168.7 -82.3,-168.69 -82.3,-168.68 -82.3,-168.67 -82.3,-168.66 -82.3,-168.65 -82.3,-168.64 -82.3,-168.63 -82.3,-168.62 -82.3,-168.61 -82.3,-168.6 -82.3,-168.6 -82.31,-168.6 -82.32,-168.6 -82.33,-168.6 -82.34,-168.6 -82.35,-168.6 -82.36,-168.6 -82.37,-168.6 -82.38,-168.6 -82.39,-168.6 -82.4,-168.61 -82.4,-168.62 -82.4,-168.63 -82.4,-168.64 -82.4,-168.65 -82.4,-168.66 -82.4,-168.67 -82.4,-168.68 -82.4,-168.69 -82.4,-168.7 -82.4,-168.7 -82.39,-168.7 -82.38,-168.7 -82.37,-168.7 -82.36,-168.7 -82.35,-168.7 -82.34,-168.7 -82.33,-168.7 -82.32,-168.7 -82.31,-168.7 -82.3))"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "The LISSARD project (Lake and Ice Stream Subglacial Access Research Drilling) is one of three research components of the WISSARD integrative initiative (Whillans Ice Stream Subglacial Access Research Drilling) that is being funded by the Antarctic Integrated System Science Program of NSF\u0027s Office of Polar Programs, Antarctic Division. The overarching scientific objective of WISSARD is to assess the role of water beneath a West Antarctic ice stream in interlinked glaciological, geological, microbiological, geochemical, and oceanographic systems. The LISSARD component of WISSARD focuses on the role of active subglacial lakes in determining how fast the West Antarctic ice sheet loses mass to the global ocean and influences global sea level changes. The importance of Antarctic subglacial lakes has only been recently recognized, and the lakes have been identified as high priority targets for scientific investigations because of their unknown contributions to ice sheet stability under future global warming scenarios. LISSARD has several primary science goals: A) To provide an observational basis for improving treatments of subglacial hydrological and mechanical processes in models of ice sheet mass balance and stability; B) To reconstruct the past history of ice stream stability by analyzing archives of past basal water and ice flow variability contained in subglacial sediments, porewater, lake water, and basal accreted ice; C) To provide background understanding of subglacial lake environments to benefit RAGES and GBASE (the other two components of the WISSARD project); and D) To synthesize data and concepts developed as part of this project to determine whether subglacial lakes play an important role in (de)stabilizing Antarctic ice sheets. We propose an unprecedented synthesis of approaches to studying ice sheet processes, including: (1) satellite remote sensing, (2) surface geophysics, (3) borehole observations and measurements and, (4) basal and subglacial sampling.\nThe latest report of the Intergovernmental Panel on Climate Change recognized that the greatest uncertainties in assessing future global sea-level change stem from a poor understanding of ice sheet dynamics and ice sheet vulnerability to oceanic and atmospheric warming. Disintegration of the WAIS (West Antarctic Ice Sheet) alone would contribute 3-5 m to global sea-level rise, making WAIS a focus of scientific concern due to its potential susceptibility to internal or ocean-driven instability. The overall WISSARD project will test the overarching hypothesis that active water drainage connects various subglacial environments and exerts major control on ice sheet flow, geochemistry, metabolic and phylogenetic diversity, and biogeochemical transformations.\nSocietal Relevance: Global warming, melting of ice sheets and consequential sea-level rise are of high societal relevance. Science Resource Development: After a 9-year hiatus WISSARD will provide the US-science community with a renewed capability to access and study sub-ice sheet environments. Developing this technological infrastructure will benefit the broader science community and assets will be accessible for future use through the NSF-OPP drilling contractor. Furthermore, these projects will pioneer an approach implementing recommendations from the National Research Council committee on Principles of Environmental Stewardship for the Exploration and Study of Subglacial Environments (2007). Education and Outreach (E/O): These activities are grouped into four categories: i) increasing student participation in polar research by fully integrating them in our research programs; ii) introducing new investigators to the polar sciences by incorporating promising young investigators in our programs, iii) promotion of K-12 teaching and learning programs by incorporating various teachers and NSTA programs, and iv) reaching a larger public audience through such venues as popular science magazines, museum based activities and videography and documentary films. In summary, WISSARD will promote scientific exploration of Antarctica by conveying to the public the excitement of accessing and studying what may be some of the last unexplored aquatic environments on Earth, and which represent a potential analogue for extraterrestrial life habitats on Europa and Mars.", "east": -168.6, "geometry": ["POINT(-168.65 -82.35)"], "keywords": "Antarctica; Biota; Diatom; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Lake Whillans; Paleoclimate; Ross Sea; Southern Ocean; Subglacial Lake; WISSARD", "locations": "Antarctica; Lake Whillans; Ross Sea; Southern Ocean", "north": -82.3, "nsf_funding_programs": null, "persons": "Powell, Ross", "project_titles": "Collaborative Research: Integrative Study of Marine Ice Sheet Stability \u0026 Subglacial Life Habitats in W Antarctica - Lake \u0026 Ice Stream Subglacial Access Research Drilling (LISSARD)", "projects": [{"proj_uid": "p0000105", "repository": "USAP-DC", "title": "Collaborative Research: Integrative Study of Marine Ice Sheet Stability \u0026 Subglacial Life Habitats in W Antarctica - Lake \u0026 Ice Stream Subglacial Access Research Drilling (LISSARD)"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -82.4, "title": "Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats in W Antarctica - Lake and Ice Stream Subglacial Access Research Drilling (LISSARD)", "uid": "600154", "west": -168.7}, {"awards": "1043690 Scherer, Reed", "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": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "Intellectual Merit: Diatom abundance in sediment cores is typically used as a proxy for paleo primary productivity. This record is complicated by variable preservation, with most loss occurring in the water column via dissolution and zooplankton grazing. This study will investigate preservational biases via a series of controlled experiments to create proxies of original productivity based on morphological changes associated with diatom dissolution and fracture. The PIs will utilize fresh diatoms from culture. Specific objectives include: (1) Linking changes in diatom morphology to availability of dissolved silica and other physical and chemical parameters; (2) Documenting the dissolution process under controlled conditions; (3) Assessment of changes in morphology and diatom surface roughness with increased dissolution; (4) Documenting the physical effects of grazing and fecal pellet formation on diatom fragmentation and dissolution; and (5) Analyzing the impact of diatom dissolution on silica and carbon export. These objectives will be achieved by growing Southern Ocean diatom species in the laboratory under differing physical and chemical conditions; controlled serial dissolution experiments on cultured diatoms; analysis of the dissolution process by imaging frustules under scanning electron microscopy (SEM) and with micro-analysis of surface texture by atomic force microscopy (AFM); making the cultures available to krill and other live zooplankton crustaceans in order to analyze the specific effects of grazing and pelletization on diatom morphology; and comparing experimental results with natural plankton, sediment trap material, and selected Holocene, Pleistocene and Pliocene sediment core material.\nBroader impacts: This work will contribute to understanding of the use of diatom abundance as an indicator of paleoproductivity. The proposed experiments are multi-disciplinary in nature. Importantly, the project was designed, and the proposal largely written, by a Ph.D. candidate. The research proposed here will lead to peer-reviewed publications and provide a base for future studies over the course of an extremely promising scientific career. The project will also support an undergraduate research student at NIU. The PI is heavily involved in science outreach, including classroom visits, museum events and webinars related to evolution and climate change, and is active with NSF-funded outreach activities linked to the ANDRILL and WISSARD programs. He will continue these efforts with this project.", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Biota; Diatom; Marine Sediments; Oceans; Sediment Core; Southern Ocean", "locations": "Antarctica; Southern Ocean", "north": -60.0, "nsf_funding_programs": null, "persons": "Haji-Sheikh, Michael; Scherer, Reed Paul", "project_titles": "Southern Ocean Diatom Taphonomy and Paleoproductivity: A Laboratory Study of Silica Degradation and Export", "projects": [{"proj_uid": "p0000360", "repository": "USAP-DC", "title": "Southern Ocean Diatom Taphonomy and Paleoproductivity: A Laboratory Study of Silica Degradation and Export"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Southern Ocean Diatom Taphonomy and Paleoproductivity: A Laboratory Study of Silica Degradation and Export", "uid": "600127", "west": -180.0}, {"awards": "0542111 Lonsdale, Darcy", "bounds_geometry": ["POINT(-166.287 -76.5799)"], "date_created": "Sat, 01 Jan 2011 00:00:00 GMT", "description": "Recent studies of marine ecosystems show conflicting evidence for trophic cascades, and in particular the relative strength of the crustacean zooplankton-phytoplankton link. The Ross Sea is a natural laboratory for investigating this apparent conflict. It is a site of seasonally high abundances of phytoplankton, characterized by regions of distinct phytoplankton taxa; the southcentral polynya is strongly dominated by the colony-forming prymnesiophyte Phaeocystis antarctica, while coastal regions of this sea are typically dominated by diatoms or flagellate species. Recent studies indicate that, while the south-central polynya exhibits a massive phytoplankton bloom, the poor food quality of P. antarctica for many crustacean zooplankton prevents direct utilization of much of this phytoplankton bloom. Rather, evidence suggests that indirect utilization of this production may be the primary mechanism by which carbon and energy become available to those higher trophic levels. Specifically, we hypothesized that nano- and microzooplankton constitute an important food source for crustacean zooplankton (largely copepods and juvenile euphausiids) during the summer period in the Ross Sea where the phytoplankton assemblage is dominated by the prymnesiophyte. In turn, we also hypothesize that predation by copepods (and other Crustacea) controls and structures the species composition of these protistan assemblages. We occupied stations in the south-central Ross Sea Polynya (RSP) and Terra Nova Bay (TNB) during austral summer to test these hypotheses. We hypothesized that the diatom species that dominate the phytoplankton assemblage in TNB constitute a direct source of nutrition to herbivorous/omnivorous zooplankton (relative to the situation in the south-central RSP). That is, the contribution of heterotrophic protists to crustacean diets will be reduced in TNB. Our research addressed fundamental gaps in our knowledge of food web structure and trophic cascades.", "east": -166.287, "geometry": ["POINT(-166.287 -76.5799)"], "keywords": "Antarctica; Biota; Crustacea; Oceans; Phytoplankton; Ross Sea; Southern Ocean", "locations": "Ross Sea; Antarctica; Southern Ocean", "north": -76.5799, "nsf_funding_programs": null, "persons": "Lonsdale, Darcy", "project_titles": "Collaborative Research: Do Crustacean Zooplankton Play a Pivotal Role in Structuring Heterotrophic Plankton Communities in the Ross Sea?", "projects": [{"proj_uid": "p0000520", "repository": "USAP-DC", "title": "Collaborative Research: Do Crustacean Zooplankton Play a Pivotal Role in Structuring Heterotrophic Plankton Communities in the Ross Sea?"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -76.5799, "title": "Do Crustacean Zooplankton Play a Pivotal Role in Structuring Heterotrophic Plankton Communities in the Ross Sea?", "uid": "600059", "west": -166.287}, {"awards": "0338163 Leventer, Amy", "bounds_geometry": ["POLYGON((-70.90391 -52.35262,-68.130917 -52.35262,-65.357924 -52.35262,-62.584931 -52.35262,-59.811938 -52.35262,-57.038945 -52.35262,-54.265952 -52.35262,-51.492959 -52.35262,-48.719966 -52.35262,-45.946973 -52.35262,-43.17398 -52.35262,-43.17398 -53.75776,-43.17398 -55.1629,-43.17398 -56.56804,-43.17398 -57.97318,-43.17398 -59.37832,-43.17398 -60.78346,-43.17398 -62.1886,-43.17398 -63.59374,-43.17398 -64.99888,-43.17398 -66.40402,-45.946973 -66.40402,-48.719966 -66.40402,-51.492959 -66.40402,-54.265952 -66.40402,-57.038945 -66.40402,-59.811938 -66.40402,-62.584931 -66.40402,-65.357924 -66.40402,-68.130917 -66.40402,-70.90391 -66.40402,-70.90391 -64.99888,-70.90391 -63.59374,-70.90391 -62.1886,-70.90391 -60.78346,-70.90391 -59.37832,-70.90391 -57.97318,-70.90391 -56.56804,-70.90391 -55.1629,-70.90391 -53.75776,-70.90391 -52.35262))"], "date_created": "Fri, 01 Jan 2010 00:00:00 GMT", "description": "The NSF-supported research icebreaker Nathaniel B. Palmer operates year-round in support of the U.S. Antarctic Program, carrying out global change studies in biological, chemical, physical, and oceanographic disciplines. \n This data set consists of underway data from leg NBP0603 on the R/V Nathaniel B. Palmer. This leg started at Punta Arenas, Chile and ended at Punta Arenas, Chile.", "east": -43.17398, "geometry": ["POINT(-57.038945 -59.37832)"], "keywords": "ADCP Acoustic Doppler Current Profiler; Antarctic Peninsula; Biota; Diatom; Electromagnetic Data; Flask Glacier; Foehn Winds; Larsen Ice Shelf; Marine Sediments; NBP0603; Oceans; Physical Ice Properties; R/v Nathaniel B. Palmer; Scar Inlet; Southern Ocean", "locations": "Larsen Ice Shelf; Southern Ocean; Flask Glacier; Scar Inlet; Antarctic Peninsula", "north": -52.35262, "nsf_funding_programs": null, "persons": "Domack, Eugene Walter", "project_titles": "Collaborative Research: Paleohistory of the Larsen Ice Shelf System: Phase II", "projects": [{"proj_uid": "p0000215", "repository": "USAP-DC", "title": "Collaborative Research: Paleohistory of the Larsen Ice Shelf System: Phase II"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -66.40402, "title": "R/V Nathaniel B. Palmer NBP0603 - Paleohistory of the Larsen Ice Shelf System", "uid": "600027", "west": -70.90391}, {"awards": "0338097 DiTullio, Giacomo", "bounds_geometry": ["POLYGON((-169.94 -52.24,-169.449 -52.24,-168.958 -52.24,-168.467 -52.24,-167.976 -52.24,-167.485 -52.24,-166.994 -52.24,-166.503 -52.24,-166.012 -52.24,-165.521 -52.24,-165.03 -52.24,-165.03 -54.879,-165.03 -57.518,-165.03 -60.157,-165.03 -62.796,-165.03 -65.435,-165.03 -68.074,-165.03 -70.713,-165.03 -73.352,-165.03 -75.991,-165.03 -78.63,-165.521 -78.63,-166.012 -78.63,-166.503 -78.63,-166.994 -78.63,-167.485 -78.63,-167.976 -78.63,-168.467 -78.63,-168.958 -78.63,-169.449 -78.63,-169.94 -78.63,-169.94 -75.991,-169.94 -73.352,-169.94 -70.713,-169.94 -68.074,-169.94 -65.435,-169.94 -62.796,-169.94 -60.157,-169.94 -57.518,-169.94 -54.879,-169.94 -52.24))"], "date_created": "Fri, 01 Jan 2010 00:00:00 GMT", "description": "The objectives of this proposal are to investigate the controls on the large-scale distribution and production of the two major bloom-forming phytoplankton taxa in the Southern Ocean, diatoms and Phaeocystis Antarctica. These two groups, through their involvement in the biogeochemical cycles of carbon, sulfur and nutrient elements, may have played important roles in the climate variations of the late Quaternary, and they also may be key players in future environmental change. A current paradigm is that irradiance and iron availability drive phytoplankton dynamics in the Southern Ocean. Recent work, however, suggests that carbon dioxide (CO2) concentrations may also be important in structuring algal assemblages, due to species-specific differences in the physiology. This proposal examines the interactive effects of iron, light and CO2 on the physiology, ecology and relative dominance of Phaeocystis and diatoms in the Southern Ocean. The Ross Sea is an ideal system in which to investigate the environmental factors that regulate the distribution and production of these two algal groups, since it is characterized by seasonal blooms of both P. Antarctica and diatoms that are typically separated in both space and time. This study will take the form of an interdisciplinary investigation that includes a field survey and statistical analysis of algal assemblage composition, iron, mixed layer depth, and CO2 levels in the southern Ross Sea, coupled with shipboard experiments to examine the response of diatom and P. Antarctica assemblages to high and low levels of iron, light and CO2 during spring and summer. This project will provide information on some of the major factors controlling the production and distribution of the two major bloom forming phytoplankton in the Southern Ocean and the related biogeochemical cycling of carbon, sulfur and nutrient elements. The results may ultimately advance the ability to predict how the Southern Ocean will be affected by and possibly modulate future climate change. This project will also make significant educational contributions at several levels, including the planned research involvement of graduate and undergraduate students, postdoctoral associates, a student teacher, and community outreach and educational activities. A number of activities are planned to interface the project with K-12 education. Presentations will be made at local schools to discuss the research and events of the research cruise. During the cruise there will be daily interactive email contact with elementary classrooms. Established websites will be used to allow students to learn about the ongoing research, and to allow researchers to communicate with students through text and downloaded images.", "east": -165.03, "geometry": ["POINT(-167.485 -65.435)"], "keywords": "Biota; Chemistry:fluid; Chemistry:Fluid; Diatom; Oceans; Phytoplankton; Ross Sea; Southern Ocean", "locations": "Ross Sea; Southern Ocean", "north": -52.24, "nsf_funding_programs": null, "persons": "DiTullio, Giacomo", "project_titles": "Collaborative Research: Interactive Effects of Iron, Light and Carbon Dioxide on Phytoplankton Community Dynamics in the Ross Sea", "projects": [{"proj_uid": "p0000540", "repository": "USAP-DC", "title": "Collaborative Research: Interactive Effects of Iron, Light and Carbon Dioxide on Phytoplankton Community Dynamics in the Ross Sea"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.63, "title": "Interactive Effects of Iron, Light and Carbon Dioxide on Phytoplankton Community Dynamics in the Ross Sea", "uid": "600036", "west": -169.94}, {"awards": "0739693 Ashworth, Allan", "bounds_geometry": ["POLYGON((160 -77,160.2 -77,160.4 -77,160.6 -77,160.8 -77,161 -77,161.2 -77,161.4 -77,161.6 -77,161.8 -77,162 -77,162 -77.1,162 -77.2,162 -77.3,162 -77.4,162 -77.5,162 -77.6,162 -77.7,162 -77.8,162 -77.9,162 -78,161.8 -78,161.6 -78,161.4 -78,161.2 -78,161 -78,160.8 -78,160.6 -78,160.4 -78,160.2 -78,160 -78,160 -77.9,160 -77.8,160 -77.7,160 -77.6,160 -77.5,160 -77.4,160 -77.3,160 -77.2,160 -77.1,160 -77))"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "This project studies the last vestiges of life in Antarctica from exceptionally well-preserved fossils of tundra life--mosses, diatoms, ostracods, Nothofagus leaves, wood, and insect remains recently discovered in ancient lake sediments from the McMurdo Dry Valleys. The area will be studied by an interdisciplinary team to elucidate information about climate and biogeography. These deposits offer unique and direct information about the characteristics of Antarctica during a key period in its history, the time when it was freezing. This information is critical for correlation with indirect proxies, such as though obtained from drill cores, for climate and state of the ice sheet. The results will also help understand the origin and migration of similar organisms found in South America, India and Australia. In terms of broader impacts, this project supports an early career researcher, undergraduate and graduate student research, various forms of outreach to K12 students, and extensive international collaboration. The work also has societal relevance in that the outcomes will offer direct constraints on Antarctica\u0027s ice sheet during a time with atmospheric CO2 contents similar to those of the earth in the coming centuries, and thus may help predictive models of sea level rise.", "east": 162.0, "geometry": ["POINT(161 -77.5)"], "keywords": "Antarctica; Geochronology; Geology/Geophysics - Other; GPS; Solid Earth", "locations": "Antarctica", "north": -77.0, "nsf_funding_programs": null, "persons": "Ashworth, Allan; Lewis, Adam", "project_titles": "Collaborative Research: Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains", "projects": [{"proj_uid": "p0000188", "repository": "USAP-DC", "title": "Collaborative Research: Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains", "uid": "600081", "west": 160.0}]

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