| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | April 4, 2013 |
| Latest Amendment Date: | January 23, 2018 |
| Award Number: | 1246378 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Douglas Kowalewski
dkowalew@nsf.gov (703)292-2181 OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | April 1, 2013 |
| End Date: | January 31, 2019 (Estimated) |
| Total Intended Award Amount: | $267,712.00 |
| Total Awarded Amount to Date: | $310,401.00 |
| Funds Obligated to Date: |
FY 2018 = $42,689.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
4202 E FOWLER AVE TAMPA FL US 33620-5800 (813)974-2897 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
140 7th Ave S St Petersburg FL US 33701-5016 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ANT Earth Sciences |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
Intellectual Merit:
Southern Ocean processes play an important role in Late Quaternary glacial-interglacial climate change. However, the direct influence of newly upwelled warm nutrient-rich Circumpolar Deep Water on the Antarctic cryosphere remains speculative. The PI proposes to test the hypothesis that Circumpolar Deep Water-derived ocean heat negatively impacts the mass-balance of Antarctica?s ice sheets during deglaciations using precisely dated late Quaternary paleoceanographic studies of Antarctic margin sediments and a suite of geochemical proxies measured on three existing glacial marine sediment cores from the Prydz Channel, Antarctica. Specifically, the PI will use these data to reconstruct the Late Quaternary history of the Lambert Glacier/Amery Ice Shelf system; evaluate the timing, speed, and style of retreat of the Lambert Glacier/Amery Ice Shelf system during the last deglaciation, and to assess the impact of Circumpolar Deep Water intrusions on the Lambert Glacier/Amery Ice Shelf system in the Late Quaternary. Diatom bound radiocarbon and optically stimulated luminescence techniques will be used to obtain precise stratigraphic age control for the Prydz Channel siliceous muddy ooze intervals. In addition, the PI will measure sedimentary 10Be concentrations to determine the origin of the siliceous muddy ooze units and to track past changes in the position of the ice shelf front.
Broader impacts:
This proposal will support an early career female scientist and will provide professional development and research experiences for women/minority graduate and undergraduate students. The PI will take advantage of USF?s Oceanography Camp for Girls.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Marine sediments, collected from Prydz Bay, East Antarctica, were analyzed to: 1) reconstruct the region’s paleoenvironment over the last 30,000 years, 2) evaluate of the timing, speed, and style of ice retreat during the last deglaciation (18-10 thousand years ago), and 3) identify the role of ocean warming on regional ice extent.
Intellectual Merit: Results indicate that Lambert-Amery outlet glacier, which drains ~16% of the East Antarctic Ice Sheet, had retreated from the continental shelf edge by at least 30,000 years ago, before the Last Glacial Maximum (~25-20 thousand years ago). Between ~30,000 and 15,000 years ago, the system advanced/retreated on millennial (~1000 year) timescales, coincident with both changes in atmospheric temperature and CO2 recorded in Antarctic ice cores and Southern Ocean warming, reduced sea ice extent, and weakening of the Antarctic Circumpolar Current. This is the first time that millennial-scale variations in East Antarctica’s glacial systems have been documented in ice proximal marine sediments during the coldest climates of the last 100,000 years. Between ~14,000 and 6,000 years ago, warm ocean waters influenced the continental shelf, suggesting that ocean warming may have forced regional ice retreat. Results reveal the sensitivity of East Antarctica’s outlet glaciers to climate and ocean change on short (decadal to millennial) timescales.
Broader Impacts: The scientific results are an important first step in understand the sensitivity of the marine-based sectors of the East Antarctic Ice Sheet, which hold ~19 meters of sea level equivalent ice, to ongoing and future environmental change. This project funded an early career woman Assistant Professor during critical pre-tenure years. The PI was awarded tenure during the project. The project funded the primary research of a Latina Ph.D. student, who is working to broaden participation of underrepresented minorities in the geosciences. Her research outcomes enabled her participation on three oceanographic cruises to Antarctica (including an International Ocean Discovery Program expedition) and a recently resulted in a post-doctoral fellowship offer at Columbia University to continue Antarctic paleoclimate research.
Last Modified: 05/10/2019
Modified by: Amelia Shevenell
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