Hyporheic Exchange and Fulvic Acid Redox Reactions in an Alpine Stream/Wetland Ecosystem, Colorado Front Range
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- 作者：Matthew P. Miller ; Diane M. McKnight ; Rose M. Cory ; Mark W. Williams ; Robert L. Runkel
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：October 1, 2006
- 年：2006
- 卷：40
- 期：19
- 页码：5943 - 5949
- 全文大小：268K
- 年卷期：v.40,no.19(October 1, 2006)
- ISSN：1520-5851
文摘
The influence of hyporheic zone interactions on the redoxstate of fulvic acids and other redox active specieswas investigated in an alpine stream and adjacent wetland,which is a more reducing environment. A tracer injectionexperiment using bromide (Br-) was conducted in thestream system. Simulations with a transport model showedthat rates of exchange between the stream and hyporheiczone were rapid (
10-3 s-1). Parallel factor analysisof fluorescence spectra was used to quantify the redox stateof dissolved fulvic acids. The rate coefficient for oxidationof reduced fulvic acids (
= 6.5 × 10-3 s-1) in thestream indicates that electron-transfer reactions occurover short time scales. The rate coefficients for decay ofammonium ( = 1.2 × 10-3 s-1) and production ofnitrate ( = -1.0 × 10-3 s-1) were opposite in sign butalmost equal in magnitude. Our results suggest that fulvicacids are involved in rapid electron-transfer processesin and near the stream channel and may be important indetermining ecological energy flow at the catchment scale.
10-3 s-1). Parallel factor analysisof fluorescence spectra was used to quantify the redox stateof dissolved fulvic acids. The rate coefficient for oxidationof reduced fulvic acids ( = 6.5 × 10-3 s-1) in thestream indicates that electron-transfer reactions occurover short time scales. The rate coefficients for decay ofammonium ( = 1.2 × 10-3 s-1) and production ofnitrate ( = -1.0 × 10-3 s-1) were opposite in sign butalmost equal in magnitude. Our results suggest that fulvicacids are involved in rapid electron-transfer processesin and near the stream channel and may be important indetermining ecological energy flow at the catchment scale.