Nitrogen cycling and metabolism in the thalweg of a prairie river

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Show simple item record Dodds, Walter K. Beaulieu, J.J. Eichmiller, J.J. Fischer, J.R. Franssen, N.R. Gudder, D.A. Makinster, A.S. McCarthy, M.J. Murdock, J.N. O'Brien, J.M. Tank, J.L. Sheibley, R.W. 2012-01-13T18:52:12Z 2012-01-13T18:52:12Z 2012-01-13
dc.description.abstract Nutrient dynamics in rivers are central to global biogeochemistry. We measured ammonium (NH4 +) uptake, metabolism, nitrification, and denitrification in the thalweg, the river region of greatest flow, of the Kansas River (discharge = 14,360 L/s). We estimated gross and net uptake with a depleted 15N-NH4 + release, metabolism with diel O2 measurements, and denitrification with dissolved N2 measurements. Net ecosystem production was negative. Net NH4 + uptake length was 2.1 km when concentrations were elevated, and gross uptake length was 1.9 km at ambient concentrations. Gross uptake rate measurements were comparable to estimates made using extrapolations from data obtained from streams (systems with 1/10th or less the discharge). Calculated lengths were maximal because the isotope pulse was primarily confined to the thalweg and not the shallow side channels or backwaters. Denitrification and nitrification rates were below detection. In the Kansas River, rates of N cycling are driven by heterotrophic processes, and considerable processing of N, particularly NH4 + uptake, occurred over a few kilometers of river length, with net uptake rates of NH4 + increasing with greater NH4 + concentrations. en_US
dc.relation.uri en_US
dc.rights Copyright 2008 by the American Geophysical Union en_US
dc.subject Nitrogen cycling en_US
dc.subject Nutrient dynamics in rivers en_US
dc.subject Thalweg en_US
dc.subject Kansas River en_US
dc.subject Metabolism en_US
dc.title Nitrogen cycling and metabolism in the thalweg of a prairie river en_US
dc.type Article (publisher version) en_US 2008 en_US
dc.citation.doi doi:10.1029/2008JG000696 en_US
dc.citation.epage 11 en_US
dc.citation.issue G04029 en_US
dc.citation.jtitle Journal of Geophysical Research en_US
dc.citation.spage 1 en_US
dc.citation.volume 113 en_US
dc.contributor.authoreid wkdodds en_US
dc.contributor.authoreid fisch133 en_US
dc.contributor.authoreid dgudder en_US
dc.contributor.authoreid efranssen en_US

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