HR: 1340h
AN: H23D-1455    [Abstracts]
TI: Hyporheic Exchange and Humic Redox Reactions in an Alpine Stream/Wetland Ecosystem
AU: * Miller, M
EM: Matthew.P.Miller-1@colorado.edu
AF: Department of Civil Engineering, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th St C.B. 450, Boulder, CO 80309 United States
AU: McKnight, D
EM: Diane.Mcknight@Colorado.edu
AF: Department of Civil Engineering, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th St C.B. 450, Boulder, CO 80309 United States
AU: Cory, R
EM: Rose.M.Cory@Colorado.edu
AF: Department of Civil Engineering, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th St C.B. 450, Boulder, CO 80309 United States
AU: Williams, M
EM: markw@snobear.colorado.edu
AF: Department of Geography, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th St C.B. 450, Boulder, CO 80309 United States
AU: Runkel, R
EM: runkel@usgs.gov
AF: U.S. Geologic Survey, Box 25046 MS 415, Denver Federal Center, Lakewood, CO 80225 United States
AB: We studied the influence of hyporheic zone interactions on the redox state of the humic fraction of dissolved organic material and other redox active species in an alpine stream in the Colorado Front Range, USA. A constant-injection tracer experiment was conducted using bromide (Br-) to determine hydrologic characteristics of the stream system. The information gained from this experiment allowed us to determine that there were high rates of exchange between the main stream channel and a storage zone with a large cross-sectional area. Fluorescence spectroscopy results showed that the humic substances in filtered whole water samples from the hyporheic zone were more reduced than humic substances from the stream. Our results suggest that through hyporheic exchange reduced humic substances are transported from the hyporheic zone to the stream where they are being rapidly oxidized. In turn, hyporheic exchange from the stream carries water containing oxidized humic substances back to the hyporheic zone. These results indicate that hyporheic zone interactions influence the oxidation state of dissolved humic substances as well as other redox active species and may play an important role in determining energy flow through the entire stream system.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 1806 Chemistry of fresh water
DE: 1830 Groundwater/surface water interaction
SC: Hydrology [H]
MN: Fall Meeting 2005