@article {482,
	title = {Sustained removal of uranium from contaminated groundwater following stimulation of dissimilatory metal reduction.},
	journal = {Environ Sci Technol},
	volume = {42},
	year = {2008},
	month = {2008 Apr 15},
	pages = {2999-3004},
	abstract = {Previous field studies on in situ bioremediation of uranium-contaminated groundwater in an aquifer in Rifle, Colorado identified two distinct phases following the addition of acetate to stimulate microbial respiration. In phase I, Geobacter species are the predominant organisms, Fe(III) is reduced, and microbial reduction of soluble U(VI) to insoluble U(IV) removes uranium from the groundwater. In phase II, Fe(III) is depleted, sulfate is reduced, and sulfate-reducing bacteria predominate. Long-term monitoring revealed an unexpected third phase during which U(VI) removal continues even after acetate additions are stopped. All three of these phases were successfully reproduced in flow-through sediment columns. When sediments from the third phase were heat sterilized, the capacity for U(VI) removal was lost. In the live sediments U(VI) removed from the groundwater was recovered as U(VI) in the sediments. This contrasts to the recovery of U(IV) in sediments resulting from the reduction of U(VI) to U(IV) during the Fe(III) reduction phase in acetate-amended sediments. Analysis of 16S rRNA gene sequences in the sediments in which U(VI) was being adsorbed indicated that members of the Firmicutes were the predominant organisms whereas no Firmicutes sequences were detected in background sediments which did not have the capacity to sorb U(VI), suggesting that the U(VI) adsorption might be due to the presence of these living organisms or at least their intact cell components. This unexpected enhanced adsorption of U(VI) onto sediments following the stimulation of microbial growth in the subsurface may potentially enhance the cost effectiveness of in situ uranium bioremediation.},
	keywords = {Acetates, Adsorption, Bacteria, Colorado, Geologic Sediments, Oxidation-Reduction, RNA, Ribosomal, 16S, Sulfates, Uranium, Water Pollutants, Radioactive, Water Supply},
	issn = {0013-936X},
	author = {N{\textquoteright}guessan, Lucie A and Vrionis, Helen A and Resch, Charles T and Long, Philip E and Lovley, Derek R}
}
@article {532,
	title = {Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates.},
	journal = {Int J Syst Evol Microbiol},
	volume = {55},
	year = {2005},
	month = {2005 Jul},
	pages = {1667-74},
	abstract = {Fe(III)-reducing isolates were recovered from two aquifers in which Fe(III) reduction is known to be important. Strain Bem(T) was enriched from subsurface sediments collected in Bemidji, MN, USA, near a site where Fe(III) reduction is important in aromatic hydrocarbon degradation. Strains P11, P35(T) and P39 were isolated from the groundwater of an aquifer in Plymouth, MA, USA, in which Fe(III) reduction is important because of long-term inputs of acetate as a highway de-icing agent to the subsurface. All four isolates were Gram-negative, slightly curved rods that grew best in freshwater media. Strains P11, P35(T) and P39 exhibited motility via means of monotrichous flagella. Analysis of the 16S rRNA and nifD genes indicated that all four strains are delta-proteobacteria and members of the Geobacter cluster of the Geobacteraceae. Differences in phenotypic and phylogenetic characteristics indicated that the four isolates represent two novel species within the genus Geobacter. All of the isolates coupled the oxidation of acetate to the reduction of Fe(III) [iron(III) citrate, amorphous iron(III) oxide, iron(III) pyrophosphate and iron(III) nitrilotriacetate]. All four strains utilized ethanol, lactate, malate, pyruvate and succinate as electron donors and malate and fumarate as electron acceptors. Strain Bem(T) grew fastest at 30 degrees C, whereas strains P11, P35(T) and P39 grew equally well at 17, 22 and 30 degrees C. In addition, strains P11, P35(T) and P39 were capable of growth at 4 degrees C. The names Geobacter bemidjiensis sp. nov. (type strain Bem(T)=ATCC BAA-1014(T)=DSM 16622(T)=JCM 12645(T)) and Geobacter psychrophilus sp. nov. (strains P11, P35(T) and P39; type strain P35(T)=ATCC BAA-1013(T)=DSM 16674(T)=JCM 12644(T)) are proposed.},
	keywords = {Bacterial Proteins, Bacterial Typing Techniques, Cold Temperature, DNA, Bacterial, DNA, Ribosomal, Ferric Compounds, Fresh Water, Genes, rRNA, Geobacter, Geologic Sediments, Massachusetts, Minnesota, Molecular Sequence Data, Oxidation-Reduction, RNA, Ribosomal, 16S, Species Specificity, Water Supply},
	issn = {1466-5026},
	doi = {10.1099/ijs.0.63417-0},
	author = {Nevin, Kelly P and Holmes, Dawn E and Woodard, Trevor L and Hinlein, Erich S and Ostendorf, David W and Lovley, Derek R}
}
@article {579,
	title = {Rapid evolution of redox processes in a petroleum hydrocarbon-contaminated aquifer.},
	journal = {Ground Water},
	volume = {40},
	year = {2002},
	month = {2002 Jul-Aug},
	pages = {353-60},
	abstract = {Ground water chemistry data collected over a six-year period show that the distribution of contaminants and redox processes in a shallow petroleum hydrocarbon-contaminated aquifer has changed rapidly over time. Shortly after a gasoline release occurred in 1990, high concentrations of benzene were present near the contaminant source area. In this contaminated zone, dissolved oxygen in ground water was depleted, and by 1994 Fe(III) reduction and sulfate reduction were the predominant terminal electron accepting processes. Significantly, dissolved methane was below measurable levels in 1994, indicating the absence of significant methanogenesis. By 1996, however, depletion of solid-phase Fe(III)-oxyhydrox ides in aquifer sediments and depletion of dissolved sulfate in ground water resulted in the onset of methanogenesis. Between 1996 and 2000, water-chemistry data indicated that methanogenic metabolism became increasingly prevalent. Molecular analysis of 16S-rDNA extracted from sediments shows the presence of a more diverse methanogenic community inside as opposed to outside the plume core, and is consistent with water-chemistry data indicating a shift toward methanogenesis over time. This rapid evolution of redox processes reflects several factors including the large amounts of contaminants, relatively rapid ground water flow (approximately 0.3 m/day [approximately foot/day]), and low concentrations of microbially reducible Fe(III) oxyhydroxides ( approximately 1 micromol/g) initially present in aquifer sediments. These results illustrate that, under certain hydrologic conditions, redox conditions in petroleum hydrocarbon-contaminated aquifers can change rapidly in time and space, and that the availability of solid-phase Fe(III)-oxyhydroxides affects this rate of change.},
	keywords = {Hydrocarbons, Iron, Methane, Oxidation-Reduction, Petroleum, Soil Pollutants, Solubility, Sulfates, Water Pollutants, Water Supply},
	issn = {0017-467X},
	author = {Chapelle, Francis H and Bradley, Paul M and Lovley, Derek R and O{\textquoteright}Neill, Kathleen and Landmeyer, James E}
}
