Nanowires in sediment bacteria transport electrons extracellularly by linking distant chemical reactions to create electrical impulses

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"Bacteria lurking in sediment at the bottom of the sea are pulling off a clever trick — using an electric current to link together the chemical reactions of oxygen in water with those of sediment nutrients deeper down.

"Lars Peter Nielsen at Aarhus University in Denmark and his colleagues suggestthat a chain of bacteria work together to transport electrons from a marine sediment to the overlying water up to two centimetres away. The electrons are produced by reactions between organic matter and hydrogen sulphide in the sediment, and transported to the sediment surface where they react with oxygen.

"This means that throughout the entire system, the top layers of sediment 'breathe' for the whole, and those at the bottom 'eat' for the whole.

"The research helps to add weight to a suggestion within the geophysics and microbiology communities that bacteria can grow tiny 'wires' and hook up to form a biogeobattery — a giant natural battery that generates electrical currents." (Sanderson 2010)

"Oxygen consumption in marine sediments is often coupled to the oxidation of sulphide generated by degradation of organic matter in deeper, oxygen-free layers. Geochemical observations have shown that this coupling can be mediated by electric currents carried by unidentified electron transporters across centimetre-wide zones. Here we present evidence that the native conductors are long, filamentous bacteria. They abounded in sediment zones with electric currents and along their length they contained strings with distinct properties in accordance with a function as electron transporters. Living, electrical cables add a new dimension to the understanding of interactions in nature and may find use in technology development." (Pfeffer et al. 2012:218)

Bacteria buzzing in the seabed

Journal article
Electric currents couple spatially separated biogeochemical processes in marine sedimentNatureFebruary 23, 2010
Lars Peter Nielsen, Nils Risgaard-Petersen, Henrik Fossing, Peter Bondo Christensen, Mikio Sayama

Journal article
Filamentous bacteria transport electrons over centimetre distancesNatureOctober 23, 2012
Christian Pfeffer, Steffen Larsen, Jie Song, Mingdong Dong, Flemming Besenbacher, Rikke Louise Meyer, Kasper Urup Kjeldsen, Lars Schreiber, Yuri A. Gorby, Mohamed Y. El-Naggar, Kar Man Leung, Andreas Schramm, Nils Risgaard-Petersen, Lars Peter Nielsen

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