HR: 1330h
AN: B12B-0780    [PDF]
TI: Influence of Mn Ion on the Iron Biomineralization by an Iron-reducing Bacterium
AU: * Lee, S
EM: str0007@hanmail.net
AF: School of Earth and Environmental Sciences, Seoul National University, Shinlim-dong San 56-1, Seoul, 151-742 Korea, Republic of
AU: Roh, Y
AF: Environmental Sciences Division, Oak Ridge National Laboratory, Post Office Box 2008, Oak Ridge, TN 37831-6038 United States
AU: Lee, I
AF: School of Earth and Environmental Sciences, Seoul National University, Shinlim-dong San 56-1, Seoul, 151-742 Korea, Republic of
AU: Phelps, T J
AF: Environmental Sciences Division, Oak Ridge National Laboratory, Post Office Box 2008, Oak Ridge, TN 37831-6038 United States
AB: Manganese ion is known to be easily sorbed to iron oxide surface or co-precipitated into iron oxides structure, but the effect of manganese ion on iron biomineralization is not sufficiently understood. The objectives of this study were to examine the influence of Mn substitution and sorption on iron biomineralization and to identify biogeochemical factors determining phase distribution of Mn ion during iron biomineralization. The reductive biomineralization of Mn-substituted (Fe1-xMnxOOH) or Mn-sorbed (FeOOH plus MnCl2) akaganeite by an iron-reducing bacterium (Shewanella alga, PV-4) was investigated under ananerobic conditions at circumneutral pH (pH = 7 - 8) and at 25 deg.C. The influence of Mn ion on the iron biomineralization was explored along with effects of bicarbonate (30 - 210 mM) on biomineralization using lactate (10 mM) as an electron donor. No exogenous electron carrier substance (i.e., anthraquinone disulfonate) or reducing agent (i.e., cysteine) was added to the anaerobic medium. Solid phases and aqueous chemistry were characterized after incubations with both of the iron-reducing bacterium and Mn-substituted or Mn-sorbed akaganeite for 30 days. The iron reducing bacterium, S. alga, mainly formed siderite (FeCO3), green rust [Fe2+Fe3+(OH)16CO3ú4H2O], and magnetite (Fe3O4) using Mn-substituted akaganeite, while rhodochrosite (MnCO3), siderite, and magnetite were dominant phases using Mn-sorbed akaganeite in the bicarbonate buffered medium. Scanning electron microscopy and transmission electron microscopy with energy dispersive X-ray analysis of iron minerals formed by S. alga showed that Mn was preferentially concentrated in the siderite and green rust. This research indicates that microorganisms may affect the cyclings of Fe, Mn and C and the fate of metal contaminants in subsurface environments.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2003 Fall Meeting