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505 How does the study of agricultural streams enrich our understanding of nutrient spiraling?

Thursday, May 21, 2009: 8:45 AM
Ambassador West
Jennifer L. Tank , Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
Robert O. Hall Jr. , Department of Zoology and Physiology, University of Wyoming, Laramie, WY
Stephen K. Hamilton , Kellogg Biological Station, Michigan State University, Hickory Corners, MI
Patrick J. Mulholland , Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN
Bruce J. Peterson , Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA
Linda R. Ashkenas , Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR
Clifford N. Dahm , Department of Biology, University of New Mexico, Albuquerque, NM
Walter K. Dodds , Division of Biology, Kansas State University, Manhattan, KS
Stuart Findlay , Inst. of Ecosystem Studies, Millbrook, NY
Stanley V. Gregory , Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR
Nancy B. Grimm , School of Life Sciences, Arizona State University, Tempe, AZ
Sherri L. Johnson , Pacific NW Research Station, US Forest Service, Corvallis, OR
William H. McDowell , Department of Natural Resources, University of New Hampshire, Durham, NH
Judy L. Meyer , Odum School of Ecology, University of Georgia, Athens, GA
Geoffrey C. Poole , Dept. of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT
H. Maurice Valett , Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
Jackson R. Webster , Department of Biological Sciences, Virginia Tech, Blacksburg, VA
Clay P. Arango , Depts of Biological Sciences/Geography, Central Washington University, Ellensburg, WA
Jake J. Beaulieu , US EPA, Cincinnati, OH
Melody J. Bernot , Biology, Ball State University, Muncie, IN
Amy J. Burgin , Cary Institute of Ecosystem Studies, Millbrook, NY
Chelsea Crenshaw , Department of Biology, University of New Mexico, Albuquerque, NM
Ashley M. Helton , Odum School of Ecology, University of Georgia, Athens, GA
Laura T. Johnson , School of Public and Environmental Affairs, Indiana University - Bloomington, Bloomington, IN
Bobbie R. Niederlehner , Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
Jonathan M. O'Brien , Kellogg Biological Station, Hickory Corners, MI
Jody D. Potter , Department of Natural Resources, University of New Hampshire, Durham, NH
Richard W. Sheibley , Washington Water Science Center, U. S. Geological Survey, Tacoma, WA
Daniel J. Sobota , School of Earth and Environmental Sciences, Washington State University, Vancouver Campus, Vancouver, WA
Suzanne M. Thomas , Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA
The role of agricultural streams in processing and retaining nutrients has been understudied considering the recent focus on how agriculture influences export of excess nitrogen to downstream ecosystems. Empirical measurements of nutrient spiraling in agricultural streams are few in contrast to “pristine” streams. Data from the LINXII project quantifying 15N-nitrate removal from streams of varying land use helps fill this knowledge gap. Combining data from 23 LINXII agricultural streams with a meta-analysis of 170 previously published nitrate uptake measurements, we found substantial variation in spiraling metrics among agricultural streams likely reflecting the variability in agriculture practices across sites. Uptake lengths (Sw) in agricultural streams spanned the entire range of those from the meta-analysis and nitrate Sw increased significantly with increasing discharge. The coefficient of variation in Sw was similar between LINXII and meta-analysis streams while nitrate concentrations were significantly higher in agricultural streams. Meta-analyses can identify major drivers controlling nutrient uptake. For example, we observed that agricultural practices resulting in stream channel exposure to sunlight, in an otherwise forested landscape, makes streams more "alive" (i.e. bioreactive). Effective stream management should optimize the capacity for nutrient uptake while recognizing that the type of agriculture may differentially influence potential nutrient retention.
See more of: Special Session - Advances in Stream Biogeochemistry: The Legacy and Promise of 30 Years of the Nutrient Spiralling Concept I
See more of: Special Sessions
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