HR: 17:30h
AN: B54A-07    [Abstracts]
TI: Can the Climate be Used Predict Annual Nitrogen Flux by the Mississippi River and the Extent of Gulf Hypoxia?
AU: * Donner, S D
EM: sddonner@princeton.edu
AF: Princeton University, 448 Robertson Hall Woodrow Wilson School of Public and International Affairs, Princeton, NJ 08544 United States
AU: Twine, T E
EM: twine@atmos.uiuc.edu
AF: University of Illinois, Department of Atmospheric Sciences, Urbana, Ill 61801
AU: Kucharik, C J
EM: kucharik@wisc.edu
AF: University of Wisconsin, Center for Sustainability and the Global Environment, Madison, WI 53706
AU: Oppenheimer, M
EM: omichael@princeton.edu
AF: Princeton University, 448 Robertson Hall Woodrow Wilson School of Public and International Affairs, Princeton, NJ 08544 United States
AB: The increased use of nitrogen fertilizer use in the central U.S. since the 1950s is commonly blamed for the increase in nitrogen export by the Mississippi River and the development of bottom-water hypoxia in the northern Gulf of Mexico each summer. With little change in land cover and fertilizer use in the past two decades, weather conditions have become a primary factor controlling the annual variability in nitrogen export by the Mississippi. The level of precipitation influences both leaching of nitrogen from land and fraction of that nitrogen transported downstream through the river system. Here we use historical data and the IBIS-THMB modeling system to examine whether precipitation data can be used to predict the amount of nitrate exported to the Gulf each spring. The results demonstrate that the late autumn precipitation, or soil recharge, and the early spring rainfall in the heavily fertilized central U.S. explains much of the annual variability in the spring nitrate-N export between 1960-2000 (r²=0.48). Advance forecasting using climate indices like the North Atlantic Oscillation and El Nino-Southern Oscillation may aid in the prediction of the spring nitrate flux and extent of Gulf hypoxia.
DE: 0402 Agricultural systems
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0469 Nitrogen cycling
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
SC: Biogeosciences [B]
MN: Fall Meeting 2005