HR: 17:00h
AN: H24B-05    [Abstracts]
TI: Trace Elements in Rivers of Central Alaska and Their Potential Response to Climate Change
AU: * Shiller, A M
EM: alan.shiller@usm.edu
AF: Department of Marine Science, University of Southern Mississippi, 1020 Blach Blvd., Stennis Space Center, MS 39529 United States
AU: Aiken, G R
EM: graiken@usgs.gov
AF: US Geological Survey, Water Resources Division, 3215 Marine Street, Boulder, CO 80303 United States
AU: Finlay, J
EM: jfinlay@tc.umn.edu
AF: Ecology Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108 United States
AB: Dissolved and colloidal trace element samples were collected from various rivers in central Alaska to learn how climate change-induced transformations of landscape might affect trace element mobilization. All rivers showed an early spring soil flush DOC peak with a concomitant peak in many dissolved trace elements (e.g., Cu, Fe, Pb, Zn). Drainages with significant permafrost (but no recent glaciation) generally had the highest DOC and DOC-related dissolved trace elements while glacier-fed rivers generally had the lowest dissolved concentrations and the greatest partitioning of elements to colloidal phases. These concentration contrasts appear to result from how the balance between complexation and adsorption is affected by the differing suspended loads and DOC concentrations of permafrost and glacial rivers. Mountainous rivers having little permafrost or glaciation tend to have dissolved metal concentrations intermediate between the two other types of rivers. Overall, our results indicate the type of changes in metal transport and partitioning to be expected from climate warming in central Alaska. As glacial contributions diminish, there should be less partitioning of metals to colloidal phases. If DOC transport increases due to warming and release of soil carbon, then so should the dissolved transport of certain DOC-related trace elements. However, at some point as basins currently dominated by permafrost are converted to non-permafrost basins, the dissolved transport of these elements should diminish. Thus, ultimately, dissolved metal concentrations of permafrost and glacial rivers are both likely to look more like the mountainous rivers. Because metal-DOC-pH relationships are non-linear, however, concentrations changes in certain dissolved trace elements may be large.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0461 Metals
DE: 0489 Trace element cycling (4875)
DE: 0496 Water quality
DE: 1806 Chemistry of fresh water
SC: Hydrology [H]
MN: Fall Meeting 2005