| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | July 27, 2015 |
| Latest Amendment Date: | November 18, 2015 |
| Award Number: | 1443420 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Michael E. Jackson
OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | August 1, 2015 |
| End Date: | July 31, 2019 (Estimated) |
| Total Intended Award Amount: | $203,590.00 |
| Total Awarded Amount to Date: | $211,337.00 |
| Funds Obligated to Date: |
FY 2016 = $7,747.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1425 W LINCOLN HWY DEKALB IL US 60115-2828 (815)753-1581 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
IL US 60115-2860 |
| 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): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
Abstract
During the Early Pliocene, 4.8 to 3.4 million years ago, warmer-than-present global temperatures resulted in a retreat of the Ross Ice Shelf and West Antarctic Ice Sheet. Understanding changes in ocean dynamics during times of reduced ice volume and increased temperatures in the geologic past will improve the predictive models for these conditions. The primary goal of the proposed research is to develop a new oxygen isotope record of Pliocene oceanographic conditions near the Antarctic continent. Oxygen isotope values from the carbonate tests of benthic foraminifera have become the global standard for paleo-oceanographic studies, but foraminifera are sparse in high-latitude sediment cores. This research will instead make use of oxygen isotope measurements from diatom silica preserved in a marine sediment core from the Ross Sea. The project is the first attempt at using this method and will advance understanding of global ocean dynamics and ice sheet-ocean interactions during the Pliocene. The project will foster the professional development of two early-career scientists and serve as training for graduate and undergraduate student researchers. The PIs will use this project to introduce High School students to polar/oceanographic research, as well as stable isotope geochemistry. Collaboration with teachers via NSTA and Polar Educators International will ensure the implementation of excellent STEM learning activities and curricula for younger students.
Technical Description
This project will produce a high-resolution oxygen isotope record from well-dated diatom rich sediments that have been cross-correlated with global benthic foraminifera oxygen isotope records. Diatom silica frustules deposited during the Early Pliocene and recovered by the ANDRILL Project (AND-1B) provide ideal material for this objective. Diatomite unites in the AND-1B core are nearly pure, with little evidence of opal formation. A diatom oxygen isotope record from this core offers the potential to constrain lingering uncertainties about Ross Sea and Southern Ocean paleoceanography and Antarctic Ice Sheet history during a time of high atmospheric carbon dioxide concentrations. Specifically, oxygen isotope variations will be used to constrain changes in the water temperature and/or freshwater flux in the Pliocene Ross Sea. Diatom species data from the AND-1B core have been used to infer variations in the extent and duration of seasonal sea ice coverage, sea surface temperatures, and mid-water advection onto the continental shelf. However, the diatom oxygen isotope record will provide the first direct measure of water/oxygen isotope values at the Antarctic continental margin during the Pliocene.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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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.
During the Early Pliocene, 4.8 to 3.4 million years ago, warmer-than-present global temperatures resulted in a retreat of the Ross Ice Shelf and West Antarctic Ice Sheet. Our research examines how large ice masses in Antarctica affect global conditions like ocean circulation during warm periods in the geologic past. Specifically, we look at chemical variations in ocean sediment records from McMurdo Sound; these records will improve the predictive models we use to understand how the world will look during times when global temperatures are warmer than today. The primary goal of our research is to develop a new record of Pliocene oceanographic conditions near the Antarctic continent. Oxygen isotope values from marine fossil organisms have become the global standard in paleoceanography and paleoclimatology, but many of the commonly used fossils from organisms like foraminifera are sparse in high-latitude sediment cores. Our research instead made use of oxygen isotope measurements from diatoms, marine algae that produce shells of opal instead of carbonate. The opal is preserved in a marine sediment core that was collected from beneath the Ross Ice Shelf close to the Antarctic continent. The project is the first attempt at using this method and will advance our understanding of the global ocean system and ice sheet-ocean interactions. The project fostered the professional development of two early-career scientists and served as training for graduate and undergraduate student researchers. The PIs have also used this project to introduce high school students to polar/oceanographic research, as well as stable isotope geochemistry. Collaboration with teachers via National Science Teaching Association and Polar Educators International will ensure the implementation of excellent science, technology, engineering and math (STEM) learning activities for the general public.
Last Modified: 10/28/2019
Modified by: Justin P Dodd
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