Articles | Volume 14, issue 3
https://doi.org/10.5194/bg-14-683-2017
https://doi.org/10.5194/bg-14-683-2017
Research article
 | 
10 Feb 2017
Research article |  | 10 Feb 2017

Long-distance electron transport occurs globally in marine sediments

Laurine D. W. Burdorf, Anton Tramper, Dorina Seitaj, Lorenz Meire, Silvia Hidalgo-Martinez, Eva-Maria Zetsche, Henricus T. S. Boschker, and Filip J. R. Meysman

Abstract. Recently, long filamentous bacteria have been reported conducting electrons over centimetre distances in marine sediments. These so-called cable bacteria perform an electrogenic form of sulfur oxidation, whereby long-distance electron transport links sulfide oxidation in deeper sediment horizons to oxygen reduction in the upper millimetres of the sediment. Electrogenic sulfur oxidation exerts a strong impact on the local sediment biogeochemistry, but it is currently unknown how prevalent the process is within the seafloor. Here we provide a state-of-the-art assessment of its global distribution by combining new field observations with previous reports from the literature. This synthesis demonstrates that electrogenic sulfur oxidation, and hence microbial long-distance electron transport, is a widespread phenomenon in the present-day seafloor. The process is found in coastal sediments within different climate zones (off the Netherlands, Greenland, the USA, Australia) and thrives on a range of different coastal habitats (estuaries, salt marshes, mangroves, coastal hypoxic basins, intertidal flats). The combination of a widespread occurrence and a strong local geochemical imprint suggests that electrogenic sulfur oxidation could be an important, and hitherto overlooked, component of the marine cycle of carbon, sulfur and other elements.

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Short summary
Recently, long filamentous bacteria have been reported to conduct electrons over centimetre distances in marine sediments. These so-called cable bacteria have an electricity-based metabolism, effectively turning the seafloor into a natural battery. In this study we demonstrate a global occurrence of these cable bacteria in marine sediments, spanning a large range of climate zones (off Greenland, the USA, Australia, the Netherlands) and a large range of coastal habitats.
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