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Long-distance electron transfer by cable bacteria in aquifer sediments.
ISME J. 2016 08; 10(8):2010-9.IJ

Abstract

The biodegradation of organic pollutants in aquifers is often restricted to the fringes of contaminant plumes where steep countergradients of electron donors and acceptors are separated by limited dispersive mixing. However, long-distance electron transfer (LDET) by filamentous 'cable bacteria' has recently been discovered in marine sediments to couple spatially separated redox half reactions over centimeter scales. Here we provide primary evidence that such sulfur-oxidizing cable bacteria can also be found at oxic-anoxic interfaces in aquifer sediments, where they provide a means for the direct recycling of sulfate by electron transfer over 1-2-cm distance. Sediments were taken from a hydrocarbon-contaminated aquifer, amended with iron sulfide and saturated with water, leaving the sediment surface exposed to air. Steep geochemical gradients developed in the upper 3 cm, showing a spatial separation of oxygen and sulfide by 9 mm together with a pH profile characteristic for sulfur oxidation by LDET. Bacterial filaments, which were highly abundant in the suboxic zone, were identified by sequencing of 16S rRNA genes and fluorescence in situ hybridization (FISH) as cable bacteria belonging to the Desulfobulbaceae. The detection of similar Desulfobulbaceae at the oxic-anoxic interface of fresh sediment cores taken at a contaminated aquifer suggests that LDET may indeed be active at the capillary fringe in situ.

Authors+Show Affiliations

Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany.Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany.Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany.Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus C, Denmark.Section for Microbiology, Department of Bioscience, Aarhus University, Aarhus C, Denmark. Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus C, Denmark.Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany.Institute of Groundwater Ecology, Helmholtz Zentrum München, Neuherberg, Germany.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27058505

Citation

Müller, Hubert, et al. "Long-distance Electron Transfer By Cable Bacteria in Aquifer Sediments." The ISME Journal, vol. 10, no. 8, 2016, pp. 2010-9.
Müller H, Bosch J, Griebler C, et al. Long-distance electron transfer by cable bacteria in aquifer sediments. ISME J. 2016;10(8):2010-9.
Müller, H., Bosch, J., Griebler, C., Damgaard, L. R., Nielsen, L. P., Lueders, T., & Meckenstock, R. U. (2016). Long-distance electron transfer by cable bacteria in aquifer sediments. The ISME Journal, 10(8), 2010-9. https://doi.org/10.1038/ismej.2015.250
Müller H, et al. Long-distance Electron Transfer By Cable Bacteria in Aquifer Sediments. ISME J. 2016;10(8):2010-9. PubMed PMID: 27058505.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Long-distance electron transfer by cable bacteria in aquifer sediments. AU - Müller,Hubert, AU - Bosch,Julian, AU - Griebler,Christian, AU - Damgaard,Lars Riis, AU - Nielsen,Lars Peter, AU - Lueders,Tillmann, AU - Meckenstock,Rainer U, Y1 - 2016/04/08/ PY - 2015/09/08/received PY - 2015/11/19/revised PY - 2015/11/25/accepted PY - 2016/4/9/entrez PY - 2016/4/9/pubmed PY - 2017/9/28/medline SP - 2010 EP - 9 JF - The ISME journal JO - ISME J VL - 10 IS - 8 N2 - The biodegradation of organic pollutants in aquifers is often restricted to the fringes of contaminant plumes where steep countergradients of electron donors and acceptors are separated by limited dispersive mixing. However, long-distance electron transfer (LDET) by filamentous 'cable bacteria' has recently been discovered in marine sediments to couple spatially separated redox half reactions over centimeter scales. Here we provide primary evidence that such sulfur-oxidizing cable bacteria can also be found at oxic-anoxic interfaces in aquifer sediments, where they provide a means for the direct recycling of sulfate by electron transfer over 1-2-cm distance. Sediments were taken from a hydrocarbon-contaminated aquifer, amended with iron sulfide and saturated with water, leaving the sediment surface exposed to air. Steep geochemical gradients developed in the upper 3 cm, showing a spatial separation of oxygen and sulfide by 9 mm together with a pH profile characteristic for sulfur oxidation by LDET. Bacterial filaments, which were highly abundant in the suboxic zone, were identified by sequencing of 16S rRNA genes and fluorescence in situ hybridization (FISH) as cable bacteria belonging to the Desulfobulbaceae. The detection of similar Desulfobulbaceae at the oxic-anoxic interface of fresh sediment cores taken at a contaminated aquifer suggests that LDET may indeed be active at the capillary fringe in situ. SN - 1751-7370 UR - https://www.unboundmedicine.com/medline/citation/27058505/Long_distance_electron_transfer_by_cable_bacteria_in_aquifer_sediments_ L2 - https://doi.org/10.1038/ismej.2015.250 DB - PRIME DP - Unbound Medicine ER -