| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | March 21, 2012 |
| Latest Amendment Date: | March 21, 2012 |
| Award Number: | 1215551 |
| Award Instrument: | Standard Grant |
| Program Manager: |
William J. Wiseman, Jr.
OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | April 1, 2012 |
| End Date: | March 31, 2014 (Estimated) |
| Total Intended Award Amount: | $235,903.00 |
| Total Awarded Amount to Date: | $235,903.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
10889 WILSHIRE BLVD STE 700 LOS ANGELES CA US 90024-4200 (310)794-0102 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
595 Charles E. Young Dr. East Los Angeles CA US 90095-1567 |
| 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, ANS-Arctic Natural 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
The specific goal of this research is to identify whether carbonate ?clumped isotope? thermometry can be applied to mollusks to accurately and precisely reconstruct temperatures in the Arctic. Previous work has shown that the occurrence of multiple rare isotope substitutions in carbonate minerals, also referred to as the ?clumping? of heavy isotopes into bonds with each other, is temperature dependent. This temperature proxy is also independent of the del-18O of water and the del-13C of dissolved inorganic carbon. Initial studies of biologically-precipitated calcite and aragonite by the PI and co-PI and collaborators indicate that the measurements of 13C-18O bond abundance should allow one to make a relatively assumption-free determination of the temperature at which a mineral formed. Although this new proxy looks promising, calibration of the clumped isotope thermometer at low temperatures (i.e., below 15°C) is limited. Therefore the utility of this proxy for climate reconstructions in the Arctic is unclear. This project will determine the accuracy and precision of the technique when applied to biological samples grown at Arctic temperatures and, consequently, the ability of this technique to assess paleo ocean temperatures in polar regions.
The instrumental record of temperature only goes back in time a few hundred years, at most. In order to understand the natural variability of temperature, either locally or globally, we require much longer records. To develop such records, we rely on proxy measurements for temperature. Use of such proxies requires assumptions and often imposes large error bars on the estimated temperature. This project will determine the usefulness of a new proxy in the polar regions.
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.
The Arctic is exhibiting some of the most dramatic climate changes of any region on the planet in response to rising greenhouse gas levels. Climate change in this region has the potential to have far-reaching consequences. Many studies, including the Intergovernmental Panel on Climate Change (IPCC) reports, have highlighted past time intervals such as the early Pliocene as an analogue for the climate that could result from elevated greenhouse gas levels in the future. New reconstructions of Arctic temperatures are needed to constrain the extent to which global warming is amplified at high latitudes and to help assess the sensitivity of Earth’s climate to changing carbon dioxide levels.
Therefore the aim of this project was to conduct exploratory work on an untested but potentially transformative isotopic tool for the applied study of Arctic climate evolution. This project set out to show that the technique can be usefully applied in the temperature range relevant for studying the climate history of polar environments when applied to a range of different carbonate materials.
We identified taxa that can be used for Arctic paleoclimate reconstructions, and determined the relationship between temperature and isotopic composition for modern samples. We also examined what methodologies should be used for sample preparation, and investigated the uncertainties associated with the method. The results were presented at scientific conferences and published in peer-reviewed journal articles.
This project supported several undergraduates from diverse backgrounds, as well as graduate students and a postdoctoral researcher who contributed to the project. We also discussed this work during outreach activities to school children and to the public.
Last Modified: 06/03/2014
Modified by: Aradhna Tripati
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