SS2.02 Biogeochemical Process at the Sediment-Water Interfaces
Date: Tuesday, June 11, 2002
Time: 2:15:00 PM
Location: Carson B
PetersonBJ, The Ecosystems Center, Marine Biological Lab, Woods Hole, USA,
Mulholland, P, J, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, USA,
Webster , J, R, Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, USA,
Meyer, J, L, Institute of Ecology, University of Georgia, Athens, USA,
Tank, J, L, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, USA,
The Lotic Intersite Nitrogen eXperiment brought together stream researchers from ten sites to apply new techniques to the study of nitrogen (N) cycling in headwater streams. In small streams most biotic activity occurs on substrate surfaces in either the hyporheic zone or on the streambed itself, thus the sediment-water interface was a critical focus of the research. A key contributor to the projectís success was the diversity of investigator expertise including hydrology, geomorphology, microbial ecology, biogeochemistry and food webs. A second contributor was the application of whole-stream nitrogen isotope tracer techniques to measure benthic-water column exchanges and food web transfers of nitrogen. Results have included new estimates of N uptake in streams, information on the importance of hyporheic processes in N cycling, a clearer understanding of the linkage between nutrient and metabolic processes, better information on food web structure and a new appreciation of stream to riparian zone linkages. Beginning in 2002, a follow-up project ( LINX-2) will add an applied dimension and focus on the impacts of land use on nitrate uptake and transformation in streams.