@article {600, title = {Comment on "Abiotic controls on H2 production from basalt-water reactions and implications for aquifer biogeochemistry".}, journal = {Environ Sci Technol}, volume = {35}, year = {2001}, month = {2001 Apr 1}, pages = {1556-9}, keywords = {Hydrogen, Minerals, Organic Chemicals, Oxidation-Reduction, Silicates, Water, Water Microbiology}, issn = {0013-936X}, author = {Anderson, R T and Chapelle, F H and Lovley, D R} } @article {610, title = {Enrichment of Geobacter Species in Response to Stimulation of Fe(III) Reduction in Sandy Aquifer Sediments.}, journal = {Microb Ecol}, volume = {39}, year = {2000}, month = {2000 Feb}, pages = {153-167}, abstract = {Engineered stimulation of Fe(III) has been proposed as a strategy to enhance the immobilization of radioactive and toxic metals in metal-contaminated subsurface environments. Therefore, laboratory and field studies were conducted to determine which microbial populations would respond to stimulation of Fe(III) reduction in the sediments of sandy aquifers. In laboratory studies, the addition of either various organic electron donors or electron shuttle compounds stimulated Fe(III) reduction and resulted in Geobacter sequences becoming important constituents of the Bacterial 16S rDNA sequences that could be detected with PCR amplification and denaturing gradient gel electrophoresis (DGGE). Quantification of Geobacteraceae sequences with a PCR most-probable-number technique indicated that the extent to which numbers of Geobacter increased was related to the degree of stimulation of Fe(III) reduction. Geothrix species were also enriched in some instances, but were orders of magnitude less numerous than Geobacter species. Shewanella species were not detected, even when organic compounds known to be electron donors for Shewanella species were used to stimulate Fe(III) reduction in the sediments. Geobacter species were also enriched in two field experiments in which Fe(III) reduction was stimulated with the addition of benzoate or aromatic hydrocarbons. The apparent growth of Geobacter species concurrent with increased Fe(III) reduction suggests that Geobacter species were responsible for much of the Fe(III) reduction in all of the stimulation approaches evaluated in three geographically distinct aquifers. Therefore, strategies for subsurface remediation that involve enhancing the activity of indigenous Fe(III)-reducing populations in aquifers should consider the physiological properties of Geobacter species in their treatment design.}, issn = {1432-184X}, author = {Snoeyenbos-West, O L and Nevin, K P and Anderson, R T and Lovley, D R} } @article {612, title = {Hexadecane decay by methanogenesis.}, journal = {Nature}, volume = {404}, year = {2000}, month = {2000 Apr 13}, pages = {722-3}, keywords = {Alkanes, Anaerobiosis, Bacteria, Biodegradation, Environmental, Geologic Sediments, Methane, Petroleum}, issn = {0028-0836}, doi = {10.1038/35008145}, author = {Anderson, R T and Lovley, D R} } @article {619, title = {Microbial communities associated with anaerobic benzene degradation in a petroleum-contaminated aquifer.}, journal = {Appl Environ Microbiol}, volume = {65}, year = {1999}, month = {1999 Jul}, pages = {3056-63}, abstract = {Microbial community composition associated with benzene oxidation under in situ Fe(III)-reducing conditions in a petroleum-contaminated aquifer located in Bemidji, Minn., was investigated. Community structure associated with benzene degradation was compared to sediment communities that did not anaerobically oxidize benzene which were obtained from two adjacent Fe(III)-reducing sites and from methanogenic and uncontaminated zones. Denaturing gradient gel electrophoresis of 16S rDNA sequences amplified with bacterial or Geobacteraceae-specific primers indicated significant differences in the composition of the microbial communities at the different sites. Most notable was a selective enrichment of microorganisms in the Geobacter cluster seen in the benzene-degrading sediments. This finding was in accordance with phospholipid fatty acid analysis and most-probable-number-PCR enumeration, which indicated that members of the family Geobacteraceae were more numerous in these sediments. A benzene-oxidizing Fe(III)-reducing enrichment culture was established from benzene-degrading sediments and contained an organism closely related to the uncultivated Geobacter spp. This genus contains the only known organisms that can oxidize aromatic compounds with the reduction of Fe(III). Sequences closely related to the Fe(III) reducer Geothrix fermentans and the aerobe Variovorax paradoxus were also amplified from the benzene-degrading enrichment and were present in the benzene-degrading sediments. However, neither G. fermentans nor V. paradoxus is known to oxidize aromatic compounds with the reduction of Fe(III), and there was no apparent enrichment of these organisms in the benzene-degrading sediments. These results suggest that Geobacter spp. play an important role in the anaerobic oxidation of benzene in the Bemidji aquifer and that molecular community analysis may be a powerful tool for predicting a site{\textquoteright}s capacity for anaerobic benzene degradation.}, keywords = {Anaerobiosis, Benzene, Biodegradation, Environmental, Culture Media, DNA, Bacterial, DNA, Ribosomal, Fresh Water, Geologic Sediments, Gram-Negative Anaerobic Bacteria, Molecular Sequence Data, Oxidation-Reduction, Petroleum, Phylogeny, Polymerase Chain Reaction, RNA, Ribosomal, 16S, Sequence Analysis, DNA, Water Pollutants}, issn = {0099-2240}, author = {Rooney-Varga, J N and Anderson, R T and Fraga, J L and Ringelberg, D and Lovley, D R} } @article {621, title = {Evidence against hydrogen-based microbial ecosystems in basalt aquifers}, journal = {Science}, volume = {281}, year = {1998}, month = {1998 Aug 14}, pages = {976-7}, abstract = {It has been proposed that hydrogen produced from basalt-ground-water interactions may serve as an energy source that supports the existence of microorganisms in the deep subsurface on Earth and possibly on other planets. However, experiments demonstrated that hydrogen is not produced from basalt at an environmentally relevant, alkaline pH. Small amounts of hydrogen were produced at a lower pH in laboratory incubations, but even this hydrogen production was transitory. Furthermore, geochemical considerations suggest that previously reported rates of hydrogen production cannot be sustained over geologically significant time frames. These findings indicate that hydrogen production from basalt-ground-water interactions may not support microbial metabolism in the subsurface.}, issn = {1095-9203}, author = {Anderson, R T and Chapelle, F H and Lovley, D R} } @article {635, title = {Oxidation of Polycyclic Aromatic Hydrocarbons under Sulfate-Reducing Conditions.}, journal = {Appl Environ Microbiol}, volume = {62}, year = {1996}, month = {1996 Mar}, pages = {1099-101}, abstract = {[(sup14)C]naphthalene and phenanthrene were oxidized to (sup14)CO(inf2) without a detectable lag under strict anaerobic conditions in sediments from San Diego Bay, San Diego, Calif., that were heavily contaminated with polycyclic aromatic hydrocarbons (PAHs) but not in less contaminated sediments. Sulfate reduction was necessary for PAH oxidation. These results suggest that the self-purification capacity of PAH-contaminated sulfate-reducing environments may be greater than previously recognized.}, issn = {0099-2240}, author = {Coates, J D and Anderson, R T and Lovley, D R} }