Living wires discovered along ocean floor

Cable bacteria in the mud along the seafloor.
Photo by Mingdong Dong, Jie Song and Nils Risgaard-Petersen/Aarhus University
Date:27 March 2013 Tags:, , ,

Multicellular bacteria transmit electrons across relatively enormous distances in the sea

Researchers have discovered filamentous bacteria along the seafloor that function as living power cables in order to transmit electrons thousands of cell lengths away.

The Desulfobulbus bacterial cells, which are only a few thousandths of a millimetre long each, are so tiny that they are invisible to the naked eye. And yet, under the right circumstances, they form a multicellular filament that can transmit electrons across a distance as large as 1 centimetre as part of the filament’s respiration and ingestion processes.

The findings by scientists at Aarhus University in Denmark and University of Southern California Dornsife (USC Dornsife) were published in the journal Nature.

Aarhus scientists had discovered a seemingly inexplicable electric current on the sea floor years ago. The new experiments revealed that these currents are mediated by a hitherto unknown type of long, multicellular bacteria that act as living power cables.

“Until we found the cables we imagined something co-operative where electrons were transported through external networks between different bacteria. It was indeed a surprise to realise, that it was all going on inside a single organism,” said Lars Peter Nielsen of the Aarhus Department of Bioscience, and a corresponding author of the Nature paper.

The team studied bacteria living in marine sediments that power themselves by oxidising hydrogen sulphide. Cells at the bottom live in a zone that is poor in oxygen but rich in hydrogen sulphide. Cells at the top live in an area rich in oxygen but poor in hydrogen sulphide.

The solution? They form long chains that transport individual electrons from the bottom to the top, completing the chemical reaction and generating life-sustaining energy.

Source: USC Dornsife


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