NSF Org:	OPP Office of Polar Programs (OPP)
Recipient:	UNIVERSITY OF GEORGIA RESEARCH FOUNDATION, INC.
Initial Amendment Date:	December 27, 2002
Latest Amendment Date:	December 6, 2007
Award Number:	0234249
Award Instrument:	Standard Grant
Program Manager:	Roberta Marinelli OPP  Office of Polar Programs (OPP) GEO  Directorate for Geosciences
Start Date:	January 1, 2003
End Date:	June 30, 2008 (Estimated)
Total Intended Award Amount:	$0.00
Total Awarded Amount to Date:	$636,912.00
Funds Obligated to Date:	FY 2003 = $627,912.00 FY 2004 = $9,000.00
History of Investigator:	James Hollibaugh (Principal Investigator) aquadoc@uga.edu
Recipient Sponsored Research Office:	University of Georgia Research Foundation Inc 310 E CAMPUS RD RM 409 ATHENS GA  US  30602-1589 (706)542-5939
Sponsor Congressional District:	10
Primary Place of Performance:	University of Georgia 623 BOYD GRADUATE RESEARCH CTR ATHENS GA  US  30602-0001
Primary Place of Performance Congressional District:	10
Unique Entity Identifier (UEI):	NMJHD63STRC5
Parent UEI:
NSF Program(s):	ANT Organisms & Ecosystems
Primary Program Source:	0100CYXXDB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):	0000, 9169, EGCH, OTHR
Program Element Code(s):	511100
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.078

ABSTRACT

This project will investigate the distribution, phylogenetic affinities and ecological aspects of ammonium-oxidizing bacteria in the Palmer Long-Term Ecological Research study area. Ammonia oxidation is the first step in the conversion of regenerated nitrogen to dinitrogen gas via denitrification, a 3-step pathway mediated by three distinct guilds of bacteria. As such, ammonia oxidation is important to the global nitrogen cycle. Ammonia oxidation and the overall process of nitrification-denitrification have received little attention in polar oceans where it is significant and where the effects of climate change on biogeochemical rates are likely to be pronounced. The goals of the studies proposed here are A) to obtain more conclusive information concerning composition of Antarctic ammonia oxidizers; B) to begin characterizing their ecophysiology and ecology; and C) to obtain cultures of the organism for more detailed studies. Water column and sea ice AOB assemblages will be characterized phylogenetically and the different kinds of AOB in various samples will be quantified. Nitrification rates will be measured across the LTER study area in water column, sea ice and sediment samples. Grazing rates on AOB will be determined and their sensitivity to UV light evaluated. In addition, the significance of urea nitrogen as a source of reduced nitrogen to AOB will be assessed and the temperature response of nitrification over temperature ranges appropriate to polar regions will be evaluated. This work will provide insights into the ecology of AOB and the knowledge needed to model how water column nitrification will respond to changes in the polar ecosystems accompanying global climate change.

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