Aquatic Sciences Meeting, Albuquerque 2001

SS02 Photochemical Reactions In Surface Waters: A Major Issue in the 21st Century? (Environmental Connections)

Date: Friday, February 16, 2001, Time: 10:30:00 AM

Location: San Miguel

Cooper, W, J, UNC Wilmington, Wilmington, USA, cooperw@uncwil.edu

Scully, N, M, UNC Wilmington, Wilmington, USA, Scullyn@uncwil.edu

Wilson, C, L, Univeristy of Montana, Missoula, USA,

Hinman, N, W, Univeristy of Montana, Missoula, USA, nhinman@selway.umt.edu

Jaffe, R, , Florida International University, Miami, USA, jaffer@servms.fiu.edu

Photochemical Modeling of Hydrogen Peroxide Formation in the Yellowstone National Park Hot Springs

Recent studies have demonstrated that photochemical processes are important in the geochemistry of the hot springs in Yellowstone National Park. Published studies have been reported on the diel cycling of H2O2 and iron in four of the springs. We are now examining the nature of the organic matter and the single wavelength quantum yields for the production of H2O2 in more detail. Preliminary evidence from absorption spectra and dissolved organic matter characterization techniques indicate that the action spectra for hydrogen peroxide will be atypical relative to other published data. It is also unclear whether the organic matter is solely responsible for the field observations that we have made. Synchronous fluorescent studies have shown that the organic matter from one hot spring is unlike any other naturally occurring organic matter that is found in aquatic environments such as lakes, wetlands and oceans. Furthermore, the organic matter concentrations in at least two of the hot springs is very low and would not account for the H2O2 cycling observed, if published quantum yields are used to model the diel cycling of hydrogen peroxide. This will be the first attempt at modeling a photochemical reaction product in hot springs and will be essential to our overall understanding of the photochemistry and biogeochemistry representative of paleo environments.

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Aquatic Sciences Meeting, Albuquerque 2001

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