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Discriminating between Biological and Hydrological Controls of Hyporheic Denitrification across a Land Use Gradient in Nine Western Wyoming Streams

I studied nine streams near Grand Teton National Park, Wyoming, covering a land use gradient (urban, agricultural, and forested) to assess influences of land use on denitrification rates and hyporheic exchange. I hypothesized denitrification in the hyporheic zone is governed by availability of chemical substrates and hydrologic transport. I tested this hypothesis by coupling measurements of denitrification potentials in hyporheic sediments with a 2-storage zone solute transport model. Denitrification potentials were lowest on average in hyporheic sediments from forested streams and highest from agricultural streams. Modeling results suggest, on average, agricultural sites are transport-limited by having the slowest exchange rate with hyporheic zone and longest transport before entering storage. Land use influences the capacity for hyporheic denitrification in two ways 1) agricultural and urban practices supply substrates that build the microbial potential for denitrification and 2) agricultural and urban activities alter channel form and substrates, limiting hyporheic exchange.

Identiferoai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-1070
Date01 May 2008
CreatorsMyers, Andrew Kenneth
PublisherDigitalCommons@USU
Source SetsUtah State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceAll Graduate Theses and Dissertations
RightsCopyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact Andrew Wesolek (andrew.wesolek@usu.edu).

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