2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/22/2018 | 11:45 AM - 12:00 PM | STREAM NITROGEN FLUXES UNDER VARIABLE NUTRIENT LOADING | 330 B
STREAM NITROGEN FLUXES UNDER VARIABLE NUTRIENT LOADING
Nitrogen fixation can contribute large fluxes of dissolved nitrogen gas (N2) into aquatic biofilms, frequently in low nitrate streams. By contrast, denitrification is often studied in streams to investigate nitrate removal rates for use in remediation. We investigated both nitrogen fixation and denitrification rates across 9 streams in Wyoming and Colorado with varying nitrate concentrations. We predicted nitrogen fixation will correspond with light and gross primary production (GPP) while inversely related to denitrification and nitrate concentrations. We coupled whole stream N2 models with diel data for nitrogen fixation and 10 microcosms. Nitrogen fixation ranged from 0.0 to 0.2 g N2 m-2d-1 and GPP ranged from 1.3 to 6.2 g O2 m-2d-1. Nitrogen fixation measured in microcosms varied dielly with light levels and GPP and was high when denitrification fluxes were low. In low nitrate streams, nitrogen fixation fluxes were up to 7 times higher than denitrification. Nitrogen fixation contributed to stream nitrogen cycling, especially in streams low nitrate, low denitrification streams.
- Primary Production
- Nitrogen
- Denitrification
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Presenters/Authors
Hilary Madinger
(), University of Wyoming, hilary.madinger@gmail.com;
ASHA DISCLOSURE:
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Nonfinancial -
Robert O. Hall
(), Flathead Lake Biological Station, University of Montana, bob.hall@flbs.umt.edu;
ASHA DISCLOSURE:
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Nonfinancial -