HR: 16:00h
AN: B42E-01    [PDF]
TI: Pyrite oxidation by microbial consortia
AU: * Bostick, B C
EM: bbostick@dartmouth.edu
AF: Dartmouth College, Dept. of Earth Sciences, Hanover, NH 03755 United States
AU: Revill, K L
EM: klester@pangea.stanford.edu
AF: Stanford University, Dept. of Civil and Environ. Engineering, Stanford, CA 94305 United States
AU: Doyle, C
EM: cdoyle@pangea.stanford.edu
AF: Stanford University, Department of Geol. and Environ. Sciences, Stanford, CA 94305 United States
AU: Kendelewicz, T
EM: kendelewicz@ssrl01.slac.stanford.edu
AF: Stanford University, Department of Geol. and Environ. Sciences, Stanford, CA 94305 United States
AU: Brown, G E
EM: gordon@pangea.Stanford.EDU
AF: Dartmouth College, Dept. of Earth Sciences, Hanover, NH 03755 United States
AU: Spormann, A M
EM: spormann@stanford.edu
AF: Stanford University, Dept. of Civil and Environ. Engineering, Stanford, CA 94305 United States
AU: Fendorf, S
EM: fendorf@stanford.edu
AF: Stanford University, Department of Geol. and Environ. Sciences, Stanford, CA 94305 United States
AB: Acid mine drainage (AMD) is formed through pyrite oxidation, which produces acidity and releases toxic metals associated with pyrite and other sulfide minerals. Microbes accelerate pyrite oxidation markedly, thereby playing a major role in the production of AMD. Here, we probe pyrite oxidation by consortia of Thiobacillus ferrooxidans and thiooxidans using surface-sensitive photoelectron spectroscopy and X-ray absorption spectroscopy and compare them with surfaces oxidized through chemical and single species cultures. Microbial oxidation resulted in the formation of distinct oxidized surface species distributed non-uniformly over the pyrite surface; consortia produced a surface both more heterogeneous and more oxidized. In contrast, chemical oxidation proceeds without the build-up of passivating oxidation products. Surface morphology was not correlated with sites of nucleation or oxidation in any obvious manner. These results demonstrate that microbial oxidation occurs through a similar mechanism to chemical oxidation, but that the presence of complex microbial communities may impact the manner by which pyrite oxidation proceeds.
DE: 0330 Geochemical cycles
DE: 0400 Biogeosciences
DE: 1045 Low-temperature geochemistry
SC: Biogeosciences [B]
MN: 2003 Fall Meeting