Paper No. 14
Presentation Time: 11:45 AM
MICROBIAL CONTROLS ON ORE WEATHERING AND METAL ION MOBILITY
LESLIE, K.L.1, IHLENFELD, C.
2, OATES, C.
2, BARR, J.
3 and FOWLE, D.A.
1, (1)Department of Geology, University of Kansas, 2030 Becker Dr, Lawrence, KS 66047, (2)Geochemistry Division, Anglo American, 20 Carlton House Terrace, London, SW1Y 5AN, United Kingdom, (3)Geochemistry Division, Anglo American, 700 West Pender Street, Suite 800, Vancouver, BC V6B 1G8, Canada, kleslie@ku.edu
The influence of microorganisms in near-surface geologic settings has been found to extend to redox processes, mineral formation and dissolution, degradation of organic compounds, and metal fate and transport. Recent investigations have expanded the knowledge of deep terrestrial microbial ecology, geochemical controls on microbial diversity and microbial influence on weathering and geochemical cycling [1, 2]. We investigated a unique biofilm community located at 1.4km depth, in the Triple 7 Cu/Zn mine (Flin Flon, Canada). Isolates of a neutrophilic, halophilic
Marinobacter spp. were obtained, capable of organotrophic growth (anaerobically and aerobically), and lithotrophic growth on Fe(II). Therefore, we examined the possibility that Fe(II) oxidation could be an important biogeochemical pathway contributing to ore oxidation and weathering in the deep subsurface [3, 4].
We examined ore weathering and metal ion mobility in the deep subsurface using incubation experiments with ore types from Triple 7 and the Fe(II)-oxidizing Marinobacter isolate in both batch and column flow-through settings. The activity of the Marinobacter isolate resulted in an increase in the mobilization of Fe, S and trace metals (Cu, Zn) from all materials. These results indicate that microbial activity, specifically Fe(II) oxidation in the deep subsurface, affects the weathering and oxidation of buried sulphides and subsequent metal mobility.
[1] MacLean et al. (2007) Geomicrobiol J 24, 491-504. [2] Sahl et al. (2008) Appl. Environ. Microbiol. 74, 143-152. [3] Leslie et al. (2010) Geochimica et Cosmochimica Act 74, A583. [4] Swanner et al. (2010) Geochimica et Cosmochimica Act 74, A1013.
