The impact of temperature change on the activity and community composition of sulfate-reducing bacteria in arctic versus temperate marine sediments

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

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Isolation of sulfate-reducing bacteria from Tunisian marine sediments and description of Desulfovibrio bizertensis sp. nov.

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.64530-0 ◽

2006 ◽

Vol 56 (12) ◽

pp. 2909-2913 ◽

Cited By ~ 27

Author(s):

Olfa Haouari ◽

Marie-Laure Fardeau ◽

Laurence Casalot ◽

Jean-Luc Tholozan ◽

Moktar Hamdi ◽

...

Keyword(s):

Marine Sediments ◽

Type Strain ◽

Elemental Sulfur ◽

Novel Species ◽

Sulfate Reducing Bacteria ◽

Electron Donors ◽

Sulfate Reducing ◽

Growth Optimum ◽

Optimum Ph ◽

Reducing Bacteria

Several strains of sulfate-reducing bacteria were isolated from marine sediments recovered near Tunis, Korbous and Bizerte, Tunisia. They all showed characteristics consistent with members of the genus Desulfovibrio. One of these strains, designated MB3T, was characterized further. Cells of strain MB3T were slender, curved, vibrio-shaped, motile, Gram-negative, non-spore-forming rods. They were positive for desulfoviridin as bisulfite reductase. Strain MB3T grew at temperatures of 15–45 °C (optimum 40 °C) and at pH 6.0–8.1 (optimum pH 7.0). NaCl was required for growth (optimum 20 g NaCl l−1). Strain MB3T utilized H2 in the presence of acetate with sulfate as electron acceptor. It also utilized lactate, ethanol, pyruvate, malate, fumarate, succinate, butanol and propanol as electron donors. Lactate was oxidized incompletely to acetate. Strain MB3T fermented pyruvate and fumarate (poorly). Electron acceptors utilized included sulfate, sulfite, thiosulfate, elemental sulfur and fumarate, but not nitrate or nitrite. The G+C content of the genomic DNA was 51 mol%. On the basis of genotypic, phenotypic and phylogenetic characteristics, strain MB3T (=DSM 18034T=NCIMB 14199T) is proposed as the type strain of a novel species, Desulfovibrio bizertensis sp. nov.

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Comparative Analysis of Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in Anoxic Marine Sediments

Applied and Environmental Microbiology ◽

10.1128/aem.67.4.1922-1934.2001 ◽

2001 ◽

Vol 67 (4) ◽

pp. 1922-1934 ◽

Cited By ~ 454

Author(s):

V. J. Orphan ◽

K.-U. Hinrichs ◽

W. Ussler ◽

C. K. Paull ◽

L. T. Taylor ◽

...

Keyword(s):

Marine Sediments ◽

Sulfate Reducing Bacteria ◽

Rrna Gene ◽

Anaerobic Oxidation Of Methane ◽

Ether Lipids ◽

Methane Seep ◽

Sulfate Reducing ◽

Oxidation Of Methane ◽

Close Relatives ◽

Reducing Bacteria

ABSTRACT The oxidation of methane in anoxic marine sediments is thought to be mediated by a consortium of methane-consuming archaea and sulfate-reducing bacteria. In this study, we compared results of rRNA gene (rDNA) surveys and lipid analyses of archaea and bacteria associated with methane seep sediments from several different sites on the Californian continental margin. Two distinct archaeal lineages (ANME-1 and ANME-2), peripherally related to the orderMethanosarcinales, were consistently associated with methane seep marine sediments. The same sediments contained abundant13C-depleted archaeal lipids, indicating that one or both of these archaeal groups are members of anaerobic methane-oxidizing consortia. 13C-depleted lipids and the signature 16S rDNAs for these archaeal groups were absent in nearby control sediments. Concurrent surveys of bacterial rDNAs revealed a predominance of δ-proteobacteria, in particular, close relatives ofDesulfosarcina variabilis. Biomarker analyses of the same sediments showed bacterial fatty acids with strong 13C depletion that are likely products of these sulfate-reducing bacteria. Consistent with these observations, whole-cell fluorescent in situ hybridization revealed aggregations of ANME-2 archaea and sulfate-reducing Desulfosarcina andDesulfococcus species. Additionally, the presence of abundant 13C-depleted ether lipids, presumed to be of bacterial origin but unrelated to ether lipids of members of the orderDesulfosarcinales, suggests the participation of additional bacterial groups in the methane-oxidizing process. Although theDesulfosarcinales and ANME-2 consortia appear to participate in the anaerobic oxidation of methane in marine sediments, our data suggest that other bacteria and archaea are also involved in methane oxidation in these environments.

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