HR: 1330h
AN: B32B-0385    [PDF]
TI: Nitrogen Oxide Trace Gas Efflux and Soil N Dynamics in Response to N Inputs in Temperate Forests of the Northeastern U.S.
AU: * Venterea, R T
AF: Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545 United States
AU: Groffman, P M
AF: Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545 United States
AU: Verchot, L
AF: International Centre for Research in Agroforestry, United Nations Avenue P.O. Box 30677-00100, Nairobi, 30677-0010 Kenya
AU: Magill, A
AF: Institute for the Study of Earth, Oceans and Space University of New Hampshire, Morse Hall, Durham, NH 03824 United States
AU: Aber, J
AF: Institute for the Study of Earth, Oceans and Space University of New Hampshire, Morse Hall, Durham, NH 03824 United States
AU: Fernandez, I
AF: University of Maine Department of Plant, Soil and Environmental Sciences, 5722 Deering Hall, Orono, ME 04469-5722 United States
AU: Adams, M B
AF: USDA Forest Service, Timber and Watershed Laboratory, Parsons, WV 26287 United States
AU: Castro, M
AF: Appalachian Laboratory University of Maryland Center for Environmental Science, 301 Braddock Road, Frostburg, MD 21532 United States
AU: Lovett, G
AF: Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545 United States
AB: Forests in the northeastern U.S. continue to receive elevated inputs of nitrogen (N) in the form of atmospheric deposition. N deposition rates in this region have remained essentially constant over the past decade. Persistent N inputs to temperate forests may have impacts on local water quality, regional air quality, and the capacity of forest productivity to increase in response to increasing atmospheric carbon dioxide. Responses that become evident at the ecosystem scale may be traceable to process-level alterations in N cycling within the forest soil. During 2000 - 2001, we measured soil N cycling rates and soil-to-atmosphere exchange of N oxide trace gases at five forest sites situated along a gradient in atmospheric N deposition from West Virginia to Maine. Four of the five sites were located within long-term N addition studies. The most consistent response was an elevation in soil nitric oxide (NO) emissions, which we measured using closed-chambers. We found evidence that differences in predominant forest vegetation and/or land-use history may have resulted in differential responses with respect to NO emissions and also enhanced rates of gross and net nitrification. The data also supported the idea that atmospheric deposition of N and acidity may both combine synergistically to promote elevated rates of NO emissions due to a sequence of soil biotic and abiotic reactions.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting