'Living electric cables' found on sea floor

Scientists peering down into the mud of the Danish seafloor have discovered bacteria that functions as living power cables, transmitting electronic currents across a number of centimetres.

Researchers at the Aarhus University in Denmark and USC were surprised to find that Desulfobulbus bacterial cells, measuring only a few thousandths of millimetre across, were responsible for a seemingly inexplicable electrical source emanating from the seabed.

After conducting experiments on the bacteria, invisible to the naked eye, the team found that the current was in fact generated by the bacteria themselves, essentially acting as power cables.

It had previously thought to be impossible to move electrons over these distances, according to the researchers.  But by linking together into a multicellular filaments the bacteria were able to transmit current over distances as long as one centimetre as part of their respiration and digestion process.

At first, the scientists thought that the electrons were being generated by external networks between different bacteria. 

After studying the sediment they found that there are tens of thousands of kilometres of the bacteria under the sea floor.

“Until we found the cables, we imagined something cooperative where electrons were transported through external networks between different bacteria,” Lars Peter Nielsen of the Aarhus Department of Bioscience said.  “It was indeed a surprise to realize that it was all going on inside a single organism.”