USAP-DC

{"dp_type": "Dataset", "free_text": "Carbon-14"}

[{"awards": "1738989 Venturelli, Ryan", "bounds_geometry": ["POINT(-110.96038 -75.21526)"], "date_created": "Mon, 10 Jul 2023 00:00:00 GMT", "description": "Included in this dataset are in situ carbon-14 concentrations for a series of bedrock cores recovered from the subglacial extension of Kay Peak, a grounding-line-proximal ridge of the volcanic edifice Mount Murphy (near Thwaites and Pope glaciers). Concentrations measured in these bedrock samples have been used in the associated publication to demonstrate that the Thwaites-Pope glacier system was thinner in the Holocene than it is today. ", "east": -110.96038, "geometry": ["POINT(-110.96038 -75.21526)"], "keywords": "Antarctica; Cosmogenic Radionuclides; Mount Murphy; Subglacial Bedrock", "locations": "Mount Murphy; Antarctica", "north": -75.21526, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Venturelli, Ryan; Goehring, Brent; Balco, Gregory", "project_titles": "NSF-NERC: Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System", "projects": [{"proj_uid": "p0010165", "repository": "USAP-DC", "title": "NSF-NERC: Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Thwaites (ITGC)", "south": -75.21526, "title": "In situ 14C data from a subglacial bedrock core near Pope and Thwaites glaciers", "uid": "601705", "west": -110.96038}, {"awards": "1643716 Buizert, Christo", "bounds_geometry": ["POLYGON((-180 -67,-144 -67,-108 -67,-72 -67,-36 -67,0 -67,36 -67,72 -67,108 -67,144 -67,180 -67,180 -69.3,180 -71.6,180 -73.9,180 -76.2,180 -78.5,180 -80.8,180 -83.1,180 -85.4,180 -87.7,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87.7,-180 -85.4,-180 -83.1,-180 -80.8,-180 -78.5,-180 -76.2,-180 -73.9,-180 -71.6,-180 -69.3,-180 -67))"], "date_created": "Mon, 22 May 2023 00:00:00 GMT", "description": "We have reconstructed the atmospheric N2O mole fraction and its isotopic composition by combining data from ice cores, firn air, and atmospheric samples. The mole fraction reconstruction extends back to 1000 CE using ice cores, firn air, and atmospheric sampling; and the isotopic reconstruction extends back to 1900 CE using only firn air data. We have incorporated both newly measured and previously published data. We present new data for the mole fraction, d15Nbulk, d18O, and d15NSP values from the Styx (East Antarctica) firn air, and mole fraction from the North Greenland Eemian Ice drilling Project (NEEM) firn air. We have used published records from the Styx and NEEM ice cores, direct atmospheric measurements from the NOAA global sampling network, and firn air data, giving a total of 11 sites for N2O mole fraction, 12 sites for d15Nbulk, 11 sites for d18O, and 8 sites for d15NSP values.\r\n", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctic; Antarctica; Anthropogenic Emission; Atmosphere; Greenhouse Gas; Greenland; Ice Core Data; Nitrification And Denitrification Processes; Nitrous Oxide; Site-Specific 15N Isotopomer; Styx Glacier", "locations": "Antarctic; Greenland; Antarctica; Styx Glacier", "north": -67.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Ghosh, Sambit; Toyoda, Sakae ; Buizert, Christo ; Langenfelds, Ray L ; Yoshida, Naohiro ; Joong Kim, Seong; Ahn, Jinho ; Etheridge, David", "project_titles": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability", "projects": [{"proj_uid": "p0010341", "repository": "USAP-DC", "title": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Concentration and isotopic composition of atmospheric N2O over the last century", "uid": "601693", "west": -180.0}, {"awards": "1643664 Severinghaus, Jeffrey", "bounds_geometry": null, "date_created": "Tue, 16 Aug 2022 00:00:00 GMT", "description": "This data set comprises measurements of noble and inert gases in the firn at the DE08-OH site sampled in 2018-2019 near the summit of Law Dome, Antarctica. The data show the expected gravitational enrichment of heavy isotopes with depth, somewhat attenuated by the high accumulation rate and a near-surface well-mixed zone (convective zone), and the \"lock-in\" horizon at 68 m depth. As seen at many other sites, the heavy isotope of oxygen 18O is depleted progressively with depth within the lock-in zone due to faster gas permeation of 16O16O relative to 18O16O from compressed air bubbles.", "east": null, "geometry": null, "keywords": "Antarctica; Firn; Firn Density; Gravitational Settling; Inert Gases; Law Dome", "locations": "Law Dome; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability", "projects": [{"proj_uid": "p0010341", "repository": "USAP-DC", "title": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Law Dome DE08-OH firn air 15N, O2/N2, Ar/N2, 18O of O2", "uid": "601598", "west": null}, {"awards": "1643664 Severinghaus, Jeffrey", "bounds_geometry": null, "date_created": "Tue, 16 Aug 2022 00:00:00 GMT", "description": "This data set consists of high-precision krypton and argon isotope measurements, along with 15N and 18O of O2. This data tests the hypothesis that the 2nd order parameter 86Krexcess (86Kr/82Kr - 40Ar/36Ar) serves as a proxy indicator of past storminess, via atmospheric pressure changes that cause barometric pumping in the firn and hence greater gravitational disequilibrium in the heavier Kr atom than in Ar. These measurements were made as part of the US-Australian Law Dome DE08-OH campaign in 2018-2019. Nitrogen and dioxygen isotopes were also measured.", "east": null, "geometry": null, "keywords": "Antarctica; Ice Core; Law Dome; Noble Gas", "locations": "Law Dome; Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability", "projects": [{"proj_uid": "p0010341", "repository": "USAP-DC", "title": "Collaborative Research: Reconstructing Carbon-14 of Atmospheric Carbon Monoxide from Law Dome, Antarctica to Constrain Long-Term Hydroxyl Radical Variability"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Law Dome DE08-OH site noble gases in ice: testing the 86Krexcess proxy", "uid": "601597", "west": null}, {"awards": "1946326 Doran, Peter", "bounds_geometry": ["POLYGON((163.079602 -77.585467,163.1197073 -77.585467,163.1598126 -77.585467,163.1999179 -77.585467,163.2400232 -77.585467,163.2801285 -77.585467,163.3202338 -77.585467,163.3603391 -77.585467,163.4004444 -77.585467,163.4405497 -77.585467,163.480655 -77.585467,163.480655 -77.5924303,163.480655 -77.5993936,163.480655 -77.6063569,163.480655 -77.6133202,163.480655 -77.6202835,163.480655 -77.6272468,163.480655 -77.6342101,163.480655 -77.6411734,163.480655 -77.6481367,163.480655 -77.6551,163.4405497 -77.6551,163.4004444 -77.6551,163.3603391 -77.6551,163.3202338 -77.6551,163.2801285 -77.6551,163.2400232 -77.6551,163.1999179 -77.6551,163.1598126 -77.6551,163.1197073 -77.6551,163.079602 -77.6551,163.079602 -77.6481367,163.079602 -77.6411734,163.079602 -77.6342101,163.079602 -77.6272468,163.079602 -77.6202835,163.079602 -77.6133202,163.079602 -77.6063569,163.079602 -77.5993936,163.079602 -77.5924303,163.079602 -77.585467))"], "date_created": "Wed, 09 Feb 2022 00:00:00 GMT", "description": "Location and metadata of C-14 samples from Taylor Valley, East Antarctica", "east": 163.480655, "geometry": ["POINT(163.2801285 -77.6202835)"], "keywords": "Antarctica; Carbon-14; Sample/collection Description; Sample/Collection Description; Sample Location; Taylor Valley", "locations": "Taylor Valley; Antarctica", "north": -77.585467, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Doran, Peter; Stone, Michael", "project_titles": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers", "projects": [{"proj_uid": "p0010294", "repository": "USAP-DC", "title": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.6551, "title": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers: in situ 14C data", "uid": "601521", "west": 163.079602}, {"awards": "1341669 DeMaster, David; 0732711 Smith, Craig", "bounds_geometry": ["POLYGON((-61 -64,-60.5 -64,-60 -64,-59.5 -64,-59 -64,-58.5 -64,-58 -64,-57.5 -64,-57 -64,-56.5 -64,-56 -64,-56 -64.1,-56 -64.2,-56 -64.3,-56 -64.4,-56 -64.5,-56 -64.6,-56 -64.7,-56 -64.8,-56 -64.9,-56 -65,-56.5 -65,-57 -65,-57.5 -65,-58 -65,-58.5 -65,-59 -65,-59.5 -65,-60 -65,-60.5 -65,-61 -65,-61 -64.9,-61 -64.8,-61 -64.7,-61 -64.6,-61 -64.5,-61 -64.4,-61 -64.3,-61 -64.2,-61 -64.1,-61 -64))"], "date_created": "Fri, 19 Jun 2020 00:00:00 GMT", "description": "This file contains Pb-210 data from bulk sediments beneath the collapsed Larsen A Ice Shelf and C-14 data from the organic fraction of the same samples.", "east": -56.0, "geometry": ["POINT(-58.5 -64.5)"], "keywords": "Antarctica; Carbon-14; Larsen Ice Shelf; Lead-210; Marine Sediments; Radioisotope Analysis", "locations": "Larsen Ice Shelf; Antarctica", "north": -64.0, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Earth Sciences", "persons": "DeMaster, David; Taylor, Richard", "project_titles": "Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, a Multidisciplinary Approach -- Cryosphere and Oceans; Using Radiochemical Data from Collapsed Ice Shelf Sediments to Understand the Nature and Timing of the Benthic Response to High-Latitude Climate Change", "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"}, {"proj_uid": "p0000382", "repository": "USAP-DC", "title": "Using Radiochemical Data from Collapsed Ice Shelf Sediments to Understand the Nature and Timing of the Benthic Response to High-Latitude Climate Change"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "LARISSA", "south": -65.0, "title": "Radioisotope data (C-14 and Pb-210) from bulk sediments, Larsen A Ice Shelf", "uid": "601336", "west": -61.0}, {"awards": "1245659 Petrenko, Vasilii", "bounds_geometry": ["POINT(161.71353 -77.75855)"], "date_created": "Fri, 28 Feb 2020 00:00:00 GMT", "description": "This data set contains measurements of 14CH4 and 14CO in ice cores from Taylor Glacier, Antarctica. This includes measurements in ice from the last deglaciation (18 - 8 kyr), for the purposes of paleoatmospheric 14CH4 reconstruction. The data set also includes measurements in older ice (50 - 70 kyr) from a deep ice core, made for the purposes of studying in situ cosmogenic 14C production in ice. All data are in excel format.", "east": 161.71353, "geometry": ["POINT(161.71353 -77.75855)"], "keywords": "Antarctica; Carbon-14; Cosmogenic; Ice Core; Methane", "locations": "Antarctica", "north": -77.75855, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Petrenko, Vasilii; Dyonisius, Michael", "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": "Taylor Dome Ice Core", "south": -77.75855, "title": "Measurements of 14CH4 and 14CO in ice from Taylor Glacier: Last Deglaciation and Deep Core Results", "uid": "601260", "west": 161.71353}, {"awards": "1246148 Severinghaus, Jeffrey; 1245821 Brook, Edward J.; 1245659 Petrenko, Vasilii", "bounds_geometry": ["POLYGON((123.3 -75.1,127.138 -75.1,130.976 -75.1,134.814 -75.1,138.652 -75.1,142.49 -75.1,146.328 -75.1,150.166 -75.1,154.004 -75.1,157.842 -75.1,161.68 -75.1,161.68 -75.367,161.68 -75.634,161.68 -75.901,161.68 -76.168,161.68 -76.435,161.68 -76.702,161.68 -76.969,161.68 -77.236,161.68 -77.503,161.68 -77.77,157.842 -77.77,154.004 -77.77,150.166 -77.77,146.328 -77.77,142.49 -77.77,138.652 -77.77,134.814 -77.77,130.976 -77.77,127.138 -77.77,123.3 -77.77,123.3 -77.503,123.3 -77.236,123.3 -76.969,123.3 -76.702,123.3 -76.435,123.3 -76.168,123.3 -75.901,123.3 -75.634,123.3 -75.367,123.3 -75.1))"], "date_created": "Fri, 18 Oct 2019 00:00:00 GMT", "description": "Noble gas data from Taylor Glacier and EPICA Dome C (EDC) for mean ocean temperature reconstruction during the Last Interglacial. Also includes trace gas measurements of d18Oatm, CO2, and CH4 from Taylor Glacier from chronology construction. ", "east": 161.68, "geometry": ["POINT(142.49 -76.435)"], "keywords": "Antarctica; Carbon-14; Carbon Dioxide; Chemistry:ice; Chemistry:Ice; CO2; Dome C Ice Core; Epica; Epica Dome C; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Chemistry; Ice Core Data; Ice Core Gas Records; Ice Core Records; Isotope Data; Last Interglacial; Mass Spectrometer; Mass Spectrometry; Methane; Oxygen; Oxygen Isotope; Paleotemperature; Pleistocene; Snow/ice; Snow/Ice; Taylor Dome Ice Core; Taylor Glacier", "locations": "Epica Dome C; Taylor Glacier; Antarctica", "north": -75.1, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Shackleton, Sarah", "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": "Taylor Dome Ice Core; Dome C Ice Core", "south": -77.77, "title": "Last Interglacial Mean Ocean Temperature", "uid": "601218", "west": 123.3}, {"awards": "0839031 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(161.71965 -77.76165)"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "This award supports a project to develop a precise gas-based chronology for an archive of large-volume samples of the ancient atmosphere, which would enable ultra-trace gas measurements that are currently precluded by sample size limitations of ice cores. The intellectual merit of the proposed work is that it will provide a critical test of the \u0027clathrate hypothesis\u0027 that methane clathrates contributed to the two abrupt atmospheric methane concentration increases during the last deglaciation 15 and 11 kyr ago. This approach employs large volumes of ice (\u003e1 ton) to measure carbon-14 on past atmospheric methane across the abrupt events. Carbon-14 is an ideal discriminator of fossil sources of methane to the atmosphere, because most methane sources (e.g., wetlands, termites, biomass burning) are rich in carbon-14, whereas clathrates and other fossil sources are devoid of carbon-14. The proposed work is a logical extension to Taylor Glacier, Antarctica, of an approach pioneered at the margin of the Greenland ice sheet over the past 7 years. The Greenland work found higher-than-expected carbon-14 values, likely due in part to contaminants stemming from the high impurity content of Greenland ice and the interaction of the ice with sediments from the glacier bed. The data also pointed to the possibility of a previously unknown process, in-situ cosmogenic production of carbon-14 methane (radiomethane) in the ice matrix. Antarctic ice in Taylor Glacier is orders of magnitude cleaner than the ice at the Greenland site, and is much colder and less stratigraphically disturbed, offering the potential for a clear resolution of this puzzle and a definitive test of the cosmogenic radiomethane hypothesis. Even if cosmogenic radiomethane in ice is found, it still may be possible to reconstruct atmospheric radiomethane with a correction enabled by a detailed understanding of the process, which will be sought by co-measuring carbon-14 in carbon monoxide and carbon dioxide. The broader impacts of the proposed work are that the clathrate test may shed light on the stability of the clathrate reservoir and its potential for climate feedbacks under human-induced warming. Development of Taylor Glacier as a \u0027horizontal ice core\u0027 would provide a community resource for other researchers. Education of one postdoc, one graduate student, and one undergraduate, would add to human resources. This award has field work in Antarctica.", "east": 161.71965, "geometry": ["POINT(161.71965 -77.76165)"], "keywords": "Antarctica; Cosmogenic; Geochemistry; Ice Core Records; Paleoclimate; Radiocarbon; Taylor Glacier; Transantarctic Mountains", "locations": "Taylor Glacier; Transantarctic Mountains; Antarctica", "north": -77.76165, "nsf_funding_programs": null, "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica", "projects": [{"proj_uid": "p0000099", "repository": "USAP-DC", "title": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.76165, "title": "Measurements of in situ cosmogenic 14C from Taylor Glacier, Antarctica", "uid": "600165", "west": 161.71965}, {"awards": "1245821 Brook, Edward J.", "bounds_geometry": ["POINT(162.167 -77.733)"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "This award supports a project to use the Taylor Glacier, Antarctica, ablation zone to collect ice samples for a range of paleoenvironmental studies. A record of carbon-14 of atmospheric methane (14CH4) will be obtained for the last deglaciation and the Early Holocene, together with a supporting record of CH4 stable isotopes. In-situ cosmogenic 14C content and partitioning of 14C between different species (14CH4, C-14 carbon monoxide (14CO) and C-14 carbon dioxide (14CO2)) will be determined with unprecedented precision in ice from the surface down to ~67 m. Further age-mapping of the ablating ice stratigraphy will take place using a combination of CH4, CO2, and delta 18O of oxygen gas and H2O stable isotopes. High precision, high-resolution records of CO2, delta 13C of CO2, nitrous oxide (N2O) and N2O isotopes will be obtained for the last deglaciation and intervals during the last glacial period. The potential of 14CO2 and Krypton-81 (81Kr) as absolute dating tools for glacial ice will be investigated. The intellectual merit of proposed work includes the fact that the response of natural methane sources to continuing global warming is uncertain, and available evidence is insufficient to rule out the possibility of catastrophic releases from large 14C-depleted reservoirs such as CH4 clathrates and permafrost. The proposed paleoatmospheric 14CH4 record will improve our understanding of the possible magnitude and timing of CH4 release from these reservoirs during a large climatic warming. A thorough understanding of in-situ cosmogenic 14C in glacial ice (production rates by different mechanisms and partitioning between species) is currently lacking. Such an understanding will likely enable the use of in-situ 14CO in ice at accumulation sites as a reliable, uncomplicated tracer of the past cosmic ray flux and possibly past solar activity, as well as the use of 14CO2 at both ice accumulation and ice ablation sites as an absolute dating tool. Significant gaps remain in our understanding of the natural carbon cycle, as well as in its responses to global climate change. The proposed high-resolution, high-precision records of delta 13C of CO2 would provide new information on carbon cycle changes both during times of rising CO2 in a warming climate and falling CO2 in a cooling climate. N2O is an important greenhouse gas that increased by ~30% during the last deglaciation. The causes of this increase are still largely uncertain, and the proposed high-precision record of N2O concentration and isotopes would provide further insights into N2O source changes in a warming world. The broader impacts of proposed work include an improvement in our understanding of the response of these greenhouse gas budgets to global warming and inform societally important model projections of future climate change. The continued age-mapping of Taylor Glacier ablation ice will add value to this high-quality, easily accessible archive of natural environmental variability. Establishing 14CO as a robust new tracer for past cosmic ray flux would inform paleoclimate studies and constitute a valuable contribution to the study of the societally important issue of climate change. The proposed work will contribute to the development of new laboratory and field analytical systems. The data from the study will be made available to the scientific community and the broad public through the NSIDC and NOAA Paleoclimatology data centers. 1 graduate student each will be trained at UR, OSU and SIO, and the work will contribute to the training of a postdoc at OSU. 3 UR undergraduates will be involved in fieldwork and research. The work will support a new, junior UR faculty member, Petrenko. All PIs have a strong history of and commitment to scientific outreach in the forms of media interviews, participation in filming of field projects, as well as speaking to schools and the public about their research, and will continue these activities as part of the proposed work. This award has field work in Antarctica.", "east": 162.167, "geometry": ["POINT(162.167 -77.733)"], "keywords": "Antarctica; Atmosphere; Geochemistry; Ice Core Records; Isotope; Paleoclimate; Taylor Glacier; Transantarctic Mountains", "locations": "Taylor Glacier; Transantarctic Mountains; Antarctica", "north": -77.733, "nsf_funding_programs": null, "persons": "Brook, Edward J.", "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": "The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "uid": "600163", "west": 162.167}, {"awards": "0739698 Doran, Peter; 0739681 Murray, Alison", "bounds_geometry": ["POINT(161.931 -77.3885)"], "date_created": "Tue, 01 Jan 2013 00:00:00 GMT", "description": "Lake Vida is the largest lake of the McMurdo Dry Valleys, with an approximately 20 m ice cover overlaying a brine of unknown depth with at least 7 times seawater salinity and temperatures below -10 degrees C year-round. Samples of brine collected from ice above the main water body contain 1) the highest nitrous oxide levels of any natural water body on Earth, 2) unusual geochemistry including anomalously high ammonia and iron concentrations, 3) high microbial counts with an unusual proportion (99%) of ultramicrobacteria. The microbial community is unique even compared to other Dry Valley Lakes. The research proposes to enter, for the first time the main brine body below the thick ice of Lake Vida and perform in situ measurements, collect samples of the brine column, and collect sediment cores from the lake bottom for detailed geochemical and microbiological analyses. The results will allow the characterization of present and past life in the lake, assessment of modern and past sedimentary processes, and determination of the lake\u0027s history. The research will be conducted by a multidisciplinary team that will uncover the biogeochemical processes associated with a non-photosynthetic microbial community isolated for a significant period of time. This research will address diversity, adaptive mechanisms and evolutionary processes in the context of the physical evolution of the environment of Lake Vida. Results will be widely disseminated through publications, presentations at national and international meetings, through the Subglacial Antarctic Lake Exploration (SALE) web site and the McMurdo LTER web site. The research will support three graduate students and three undergraduate research assistants. The results will be incorporated into a new undergraduate biogeosciences course at the University of Illinois at Chicago which has an extremely diverse student body, dominated by minorities.", "east": 161.931, "geometry": ["POINT(161.931 -77.3885)"], "keywords": "Antarctica; Biota; Carbon-14; Chemistry:fluid; Chemistry:Fluid; Chemistry:ice; Chemistry:Ice; Dry Valleys; Geochronology; Ice Core Records; Lake Vida; Microbiology", "locations": "Dry Valleys; Lake Vida; Antarctica", "north": -77.3885, "nsf_funding_programs": null, "persons": "Murray, Alison", "project_titles": "Collaborative Research: Geochemistry and Microbiology of the Extreme Aquatic Environment in Lake Vida, East Antarctica", "projects": [{"proj_uid": "p0000485", "repository": "USAP-DC", "title": "Collaborative Research: Geochemistry and Microbiology of the Extreme Aquatic Environment in Lake Vida, East Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.3885, "title": "Geochemistry and Microbiology of the Extreme Aquatic Environment in Lake Vida, East Antarctica", "uid": "600080", "west": 161.931}, {"awards": "0538683 Lal, Devendra", "bounds_geometry": ["POINT(-180 -90)"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "The principal aim of this research is to determine the precise manner in which solar activity has varied in the past 1000 years. During this period, four periods of very low solar activity have been identified: Wolf (1305-1345 AD), Spoerer (1418-1540 AD), Maunder (1645-1715), and one period of high solar activity (1100-1250 A.D.) have been deduced based on available historical records of sunspot numbers and aurora. Our proposal aims to study the solar activity during the past 1000 years in detail using a new method, based on studies of polar ice, as developed earlier (Earth and Planetary Science Letters, 234, 335-349, 2005). The method is based on the fact that greater solar activity leads to production of greater magnetic fields in the heliosphere, which reduces the primary cosmic ray flux in the near Earth environment, and vice-versa. Consequently if one can measure the primary cosmic ray flux in the near Earth space, it becomes a direct measure of the solar activity. Lal et al. (Earth and Planetary Science Letters, 234, 335-349, 2005) concluded that the best way of measuring the primary cosmic ray flux would be to measure the concentration of cosmogenic in-situ produced 14C in polar ice sheets, which was discovered by Lal et al. (Nature 346, 350-352, 1990). Following this idea Lal et al. (op. cit.) measured cosmogenic in-situ produced in 19 samples from the GISP 2 core covering time range of 375-31,250 yrs B.P. Their studies showed that there were two periods of very low solar activity in this time bracket (during 8500-9500 B.P and 27,000-32,000 B.P.), and one high solar activity period during 12,000-16,000 yrs B.P. In order to provide an independent check on the veracity of the new method, we decided to apply it to the historical period, \u003c 1000 yrs B.P. The inferred Solar activities based on the study of cosmogenic in-situ produced 14C in South Pole ice samples clearly establish that there was a period of high Solar activity during 1100-1250 A.D., and a period of very low solar activity during 1416-1534 A.D, designated as the Spoerer Minimum. These results however do not confirm the proposed dates for the Dalton and the Maunder Minimum periods, predicted to be 1795-1825 A.D. and 1654-1714 A.D. respectively. Instead, our studies show that there was a long duration period of low solar activity during 1750-1860 A.D. These results make it quite clear that we should carry out more studies to fully establish the temporal behavior of the Solar activity in the past 1000 yrs.", "east": -180.0, "geometry": ["POINT(-180 -90)"], "keywords": "Antarctica; Carbon-14; Cosmos; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Paleoclimate; Solar Activity; South Pole", "locations": "South Pole; Antarctica", "north": -90.0, "nsf_funding_programs": null, "persons": "Lal, Devendra", "project_titles": "Solar Activity during the Last Millennium, Estimated from Cosmogenic in-situ 14C in South Pole and GISP2 Ice Cores", "projects": [{"proj_uid": "p0000555", "repository": "USAP-DC", "title": "Solar Activity during the Last Millennium, Estimated from Cosmogenic in-situ 14C in South Pole and GISP2 Ice Cores"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Solar activity during the last millennium, estimated from cosmogenic in-situ C14 in South Pole and GISP2 ice cores", "uid": "600058", "west": -180.0}]

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