GEOC 140 |
| Alan M. Shiller, Department of Marine Science, Department of Marine Science, University of Southern Mississippi, 1020 Blach Blvd., Stennis Space Center, MS 39529 |
| Seasonal variability in dissolved Mn and other particle-reactive trace elements has been observed in a number of river systems. In some cases this variability can be attributed to nearby seasonally reducing lakes or reservoirs. In the lower Mississippi River, such a source does not appear to provide a reasonable explanation, though. However, microbial Mn oxidation is found to occur in these waters. The rate of the oxidation depends on the water temperature and suspended load. A simple model suggests the temperature dependance of the Mn oxidation can explain the seasonal variability of dissolved Mn. Others have demonstrated that fresh, microbially-precipitated Mn oxide has a very high specific surface area. Thus, temperature-driven seasonal changes in the Mn oxidation rate might drive seasonal changes in the amount of certain adsorbing surfaces and thereby drive changes in the concentrations of other particle-reactive trace elements. |
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Microbially Mediated Manganese and Iron Oxidation in the Biosphere
8:00 AM-12:15 PM, Wednesday, March 31, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |