Microbial Reduction of Iron in Sedimentary Clays:
Implications for Subsurface Microbial Ecology and Bioremediation
EMSL Project ID
3157
Abstract
Past studies have shown that certain subsurface bacteria are capable of utilizing oxidized forms of metals as electron acceptors, coupled with oxidation of organic matter. Most studies have focused on oxides and smectite in soils and shallow sediments. No attempt has been made to study bacteria-illite interactions under conditions of a sedimentary basin, despite the fact that subsurface bacteria may play an active role in enhancing oil maturation and affecting the fate and transport of toxic contaminants.Recent discovery of an anaerobic Fe-reducing bacterium, Bacillus Infernus, from gas- and oil-bearing rock formations has placed us in a unique position to achieve the following objectives: (1) to investigate microbial utilization of Fe(III) in illite and mechanisms of microbial reduction; (2) to identify bacterial candidates with greatest potential for reduction with reasonable rates; (3) to design experimental conditions to maximize reduction efficiency; (4) to determine effects of microbial reduction on illite structure, composition, physical and chemical properties. The successful accomplishment of these goals will allow us to delineate survival mechanisms of bacteria in sedimentary basins, to design strategies to promote organic matter maturation and to remediate contaminated environments via stimulation of in-situ microbial activity. The last goal addresses direct consequences of microbial reduction on properties of clays in particular, soils and sediments in general. Several Fe-reducing bacteria will be used, and original and reduced illite samples will be analyzed by a variety of techniques.
This proposal requests access to the EMSL Mossbauer spectroscopy facility. In our previous studies, Mossbauer spectroscopy has proven to be an essential tool for quantifying Fe(II)/Fe(III) ratio in both unreduced and reduced illite samples. In collaboration with Dr. Ravi Kukkadapu, we detected a minor amount of goethite in our illite samples, and quantified the extent of reduction for both goethite and illite. The manuscript is current under review by Environmental Science and Technology. Because of the presence of goethite in our previous illite sample, our preliminary results need to be confirmed with more experiments. We have subsequently obtained pure illite samples from Australia, and we have performed more reduction experiments. We hope to continue to use Mossbauer user facility in collaboration with Dr. Ravi Kukkadapu.
Project Details
Project type
Exploratory Research
Start Date
2002-12-12
End Date
2005-12-18
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Jaisi DP, RK Kukkadapu, DD Eberl, and H Dong. 2005. "CONTROL OF FE(III) SITE OCCUPANCY ON THE RATE AND EXTENT OF MICROBIAL REDUCTION OF FE(III) IN NONTRONITE." Geochimica et Cosmochimica Acta 69(23):5429-5440.
RK Kukkadapu, JK Fredrickson, JM Zachara, DW Kennedy, HM Kostandarithes, and Dong H. 2003. "Microbial Reduction of Structural Fe(III) in Illite and Goethite." Environmental Science and Technology Vol. 37(7):1268-1276.
Seabaugh JL, H Dong, RK Kukkadapu, DD Eberl, JP Morton, and J Kim. 2006. "Microbial Reduction of Fe(III) in the Fithian and Muloorina Illites : Contrasting Extents and Rates of Bioreduction." Clays and Clay Minerals 54(1):67-79.
Zhang G, H Dong, H Jiang, RK Kukkadapu, J Kim, DD Eberl, and Z Xu. 2009. "Biomineralization Associated with Microbial Reduction of Fe3+ and Oxidation of Fe2+ in Solid Minerals ." American Mineralogist 94(7):1049-1058.