NSF Org:	OCE Division Of Ocean Sciences
Recipient:	THE TRUSTEES OF COLUMBIA UNIVERSITY IN THE CITY OF NEW YORK
Initial Amendment Date:	September 2, 2008
Latest Amendment Date:	October 10, 2012
Award Number:	0823507
Award Instrument:	Standard Grant
Program Manager:	Bilal U. Haq OCE  Division Of Ocean Sciences GEO  Directorate for Geosciences
Start Date:	September 1, 2008
End Date:	August 31, 2013 (Estimated)
Total Intended Award Amount:	$319,998.00
Total Awarded Amount to Date:	$319,998.00
Funds Obligated to Date:	FY 2008 = $319,998.00
History of Investigator:	Robert Anderson (Principal Investigator) boba@ldeo.columbia.edu Steven Goldstein (Co-Principal Investigator) Martin Fleisher (Co-Principal Investigator) Katharina Pahnke (Former Co-Principal Investigator)
Recipient Sponsored Research Office:	Columbia University 615 W 131ST ST NEW YORK NY  US  10027-7922 (212)854-6851
Sponsor Congressional District:	13
Primary Place of Performance:	Columbia University Lamont Doherty Earth Observatory Rt 9W Palisades NY  US  10964
Primary Place of Performance Congressional District:	17
Unique Entity Identifier (UEI):	F4N1QNPB95M4
Parent UEI:
NSF Program(s):	Marine Geology and Geophysics
Primary Program Source:	01000809DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):	0000, OTHR
Program Element Code(s):	162000
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050

ABSTRACT

Proposal Number NSF OCE 0823507

Project Title: Patagonia glaciation, geochemical tracers of Atlantic Meridional Overturning Circulation, and iron fertilization of the glacial South Atlantic Ocean

Abstract

Previous studies have interpreted evidence from South Atlantic sediments (between 40 and 50S latitude) to indicate that, during the last glacial period, there were (1) rapid changes in ocean currents that transport heat from the tropics to polar latitudes, and (2) rapid changes in biological productivity correlated with the changes in ocean currents. This project is designed to test the following hypotheses: 1) Changes in biological productivity were caused by the addition of iron, a growth-limiting essential nutrient, delivered to the region in the form of soil carried by icebergs from southern South America, and 2) The soil that provided the iron also carried a chemical signature (in the form of authigenic neodymium (Nd) isotopes) that introduced an artifact in the evidence used previously to infer past changes in ocean circulation.

To test these hypotheses, researchers will determine if the burial rates of organic carbon (a measure of biological productivity) and of soil from southern South America (identified by its unique composition of Nd and Sr isotopes) are correlated in sediments from cores in the mid South Atlantic at about 45°S. Research will also be conducted on fish teeth from the sediments to measure their authigenic Nd isotope composition because these fossils provide a more reliable measure of the Nd isotope composition of seawater than is obtained by leaching bulk sediments and fish teeth are not influenced by neodymium carried by soil.

Reconstructions of past climate-related changes in the ocean play a critical role in developing both conceptual and numerical models of climate variability that will ultimately serve to make predictions of future climate change, and of its consequences. Consequently, it is vital that these reconstructions be accurate. This is key broader impact of this research project. In addition, this study will both test cause and effect relationships underlying past changes in ocean biology and its role in the global carbon cycle, and test for potential artifacts that may have confused previous interpretations of climate-related changes in ocean circulation.

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