SS3.04 Biogeochemistry of DOC/DON in a Watershed Context
Date: Wednesday, June 12, 2002
Time: 10:30:00 AM
Location: Carson B
 
O'ReillyCM, University of Arizona, Tucson, USA, coreilly@geo.arizona.edu
Brooks, P, D, University of Arizona, Tucson, USA, brooks@hwr.arizona.edu
Campbell, D, H, USGS-Water Resources Division, Lakewood, USA, dhcampbe@usgs.gov
 
THE EFFECT OF WATERSHED CHARACTERISTICS ON DOC CONCENTRATION AND COMPOSITION OF LAKES IN ROCKY MOUNTAIN NATIONAL PARK
image
Dissolved organic carbon (DOC) plays a key role in physical, chemical, and biological processes in lake ecosystems. We examined the role of watershed characteristics in controlling composition and concentrations of DOC in lakes in Rocky Mountain National Park, particularly with respect to the sources and photoreactivity of fulvic acids, which can absorb UV radiation. Temporal variability in DOC concentration and composition was controlled by precipitation patterns, both on a seasonal and interannual scale. Landscape position (perched vs. flushed) further influenced site DOC response to precipitation events. Spatial differences in DOC concentration were related to elevation, vegetation, and geology/soil type. Generally, aquatically-derived fulvic acids dominated the DOC pool. Small changes in precipitation could have a strong impact on the relative contribution of terrestrial fulvic acids to the overall DOC pool. More detailed research on the processes that control the size of the mobile terrestrial DOC pool are needed to understand how these environments may respond to changes in temperature or precipitation.