Geomicrobial profile through the hyporheic zone of a historic mining flood plain
- Univ. of Montana, Missoula, MT (United States)
A unique sampling method has been developed to assist the simultaneous sampling of the geochemical and microbiological stratigraphy from surface sediment into the underlying ground water at a highly contaminated historic mining site located near Butte, Montana. These waters often contain high levels of Fe and Mn in addition to elevated amounts of As, Cd, Cu, Pb, and Zn. The aqueous geochemical profile defined three zones: surface water with high pH (7.8) and low metal concentrations (Fe(II) = 0.2ppm); ground water zone with low pH (4.5) and high metal concentrations (Fe(II) = 350ppm); and hyporheic zone, intermediate in composition between surface and ground water. The behavior of metals within this sequence is primarily controlled by geochemical conditions of the aqueous phase and is strongly influenced by oxic inflow from surface waters. General heterotrophic bacterial numbers were high in the surface sediments ({approximately}10{sup 7}cfu/cm{sup 2}) but dropped significantly ({approximately}10{sup 4}cfu/cm{sup 2}) under the surface sediment layer. Manganese oxidizing bacteria represented a large subset of the total culturable heterotrophs throughout the hyporheic zone but not in the surface sediment. A sharp transition existed at the hyporheic zone/ground water interface. Throughout a steep 10 cm gradient the pH and the culturable bacteria each dropped two orders of magnitude. Geochemically this zone contained a dense band of precipitated metals species forming as a result of mixing between hyporheic water and ground water. The results presented suggest a strong correlation between geochemical events and the indigenous microflora.
- OSTI ID:
- 37577
- Report Number(s):
- CONF-9403190-; ISBN 1-882132-28-9; TRN: IM9519%%506
- Resource Relation:
- Conference: 2. international conference on ground water ecology, Atlanta, GA (United States), 27-30 Mar 1994; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the second international conference on ground water ecology; Stanford, J.A. [ed.] [Univ. of Montana, Polson, MT (United States). Flathead Lake Biological Station]; Valett, H.M. [ed.] [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Biology]; PB: 400 p.
- Country of Publication:
- United States
- Language:
- English
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