| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | July 13, 2011 |
| Latest Amendment Date: | August 17, 2012 |
| Award Number: | 1060743 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Candace Major
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | July 15, 2011 |
| End Date: | June 30, 2016 (Estimated) |
| Total Intended Award Amount: | $575,000.00 |
| Total Awarded Amount to Date: | $575,000.00 |
| Funds Obligated to Date: |
FY 2012 = $412,209.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
266 WOODS HOLE RD WOODS HOLE MA US 02543-1535 (508)289-3542 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
266 WOODS HOLE RD WOODS HOLE MA US 02543-1535 |
| 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): |
Marine Geology and Geophysics, OCE-Ocean Sciences Research |
| Primary Program Source: |
01001213DB NSF RESEARCH & RELATED ACTIVIT |
| 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): | 47.050 |
ABSTRACT
How the tropical hydrologic cycle is responding and will respond to anthropogenic perturbations is unclear. Records of past change recorded in marine sediments offer one important avenue to explore how tropical climate responds to changes in a range of surface boundary conditions, and the mechanisms that cause these changes.
A researcher from the Woods Hole Oceanographic Institution in Massachusetts will examine the response of the tropical hydrologic cycle to a range of boundary conditions during the last 25,000 years, focusing on the Indo-Pacific region. This geographic area includes the Indo-Pacific Warm Pool (IPWP), the largest reservoir of warm surface water on earth, the major source of heat for the global atmosphere, and a location of deep atmospheric convection and heavy rainfall. Previous work by this researcher has shown that small variations in sea surface temperature of the IPWP can perturb planetary scale atmospheric circulation and atmospheric heating globally. This project will generate records of hydrologic change from core sites within the IPWP using compound-specific hydrogen and carbon isotopes of terrestrial long-chain leaf-wax fatty acids. Within the time period of interest, there will be a particular focus on abrupt, millennial-scale changes (Heinrich Event 1 and the Younger Dryas) and the last 2,000 years.
This project builds on a large body of previous work carried out by this researcher and her colleagues, and continues collaborations with organic geochemists and climate modelers for a robust and multi-faceted approach to understanding the tropical hydrologic cycle. Funding will support a postdoctoral researcher, and provide opportunities for undergraduate and high school students involvement in marine research.
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.
Intellectual Merit: We conducted the first spatial core-top calibration of carbon and hydrogen leaf wax across strong climatic gradients - from tropical wetlands to semi arid regions. Our results suggest that in the tropics, leaf wax carbon isotopes, e. g. vegetation type is largely driven by dry season water stress. This finding requires leaf wax carbon isotopes to be interpreted accordingly.
Similarly, our results confirm that once corrected for vegetation type (using carbon istopes) leaf wax hydrogen isotopes largely record mean annual precipitation.
Combining the two should allow more nuanced interpretations of past changes in the hydrologic cycle.
Our results show that the regions of the IndoPacific Warm Pool with very long or severe dry seasons expanded greatly- both southward and eastward - during the last glacial maximum. Rainfall in the rainy season did not compensate for reduced rainfall during the dry season.
Broader Impacts: Our results demonstrate that dramatic changes have occurred in past in vegetation in moist to semi-arid tropical regions due to changes in rainfall seasonality. Ongoing climate change is changing rainfall seasonality in the tropics already, and therefore changes in natural vegetation should be expected, with potential consequences for biodiversity. This project provided training for two post-doctoral scientists.
Last Modified: 09/13/2016
Modified by: Delia Oppo
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