GEOC 62 |
| Alan M. Shiller, Department of Marine Science, Department of Marine Science, University of Southern Mississippi, 1020 Blach Blvd., Stennis Space Center, MS 39529 |
| The Mississippi and Yukon Rivers are similar in both having high suspended loads and moderately alkaline pH's. However, they differ greatly in climate and the extent of human engineering. In the lower Mississippi River, seasonal variability in many dissolved metals follows a seasonal "redox pump" caused by inputs from seasonally stratified lakes and reservoirs as well as by the temperature dependance of microbial manganese oxidation. In the Yukon River there is additionally evidence of a spring pulse of trace elements associated with early season soil flushing. Greater amounts of colloidal Fe are observed in the Yukon relative to the Mississippi which may reflect the greater DOC of the Yukon. Interestingly, permafrost-dominated sub-basins in the Yukon system show relatively little seasonal concentration variability in dissolved metals. Long-term changes in the seasonal concentration variability of such basins may thus provide an indicator of the effects of climate change on the landscape. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
8:00 AM-11:30 AM, Tuesday, March 30, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |