Deep-sea bacteria conduct electrical currents on the ocean floors

Feb 25, 2010 10:01 GMT  ·  By
At left, Nielsen measures current in the sediment sample; at right, a close-up view of the sediment
   At left, Nielsen measures current in the sediment sample; at right, a close-up view of the sediment

Purely by chance, researchers have discovered another mechanism of our planet's biogeochemistry, which involves deep-sea bacteria. These microorganisms are apparently capable of conducting electrical currents across the ocean floors over incredible distances, creating an electrochemical network similar to the one envisioned by James Cameron on Pandora, the exomoon of the blockbuster Avatar. The new discovery implies that a huge series of chemical reactions, taking place hundreds of miles apart, are in fact linked together. The team behind the finding noticed this by accident, while peering over the remnants of another experiment, Wired reports.

“The cycling of elements and life at the bottom of the sea, and in soil, and anywhere else you’re short of oxygen – this could help us understand those processes,” explains scientist Lars Peter Nielsen, who is a microbiologist at the Aarhus University, in Denmark. He is also the coauthor of a new study detailing the current investigation, published in the February 24 issue of the top scientific journal Nature. The expert says that his team's goal was not to analyze deep-sea conductivity, but rather to analyze a species of sulfur bacteria that the researchers found to be very interesting. This microorganism can be found in the Aarhus Bay.

The team was aiming to thoroughly analyze the range of chemical activities the bacteria were involved in, and so they collected a few containers with seawater, and some with sulfur bacteria-free sediments. They kept the beakers for comparison throughout the study. When the investigation ended, the containers were left on their own for a few weeks, until the scientists noticed that they exhibited a very peculiar pattern of activity. The team observed that fluctuations in the oxygen level at the surface of the water samples had an almost immediate effect on chemical processes several layers down.

They argue that these changes were so fast that regular phenomena such as molecular diffusion and slow drift based on concentration differences could not explain it. “One of my colleagues saw this, and immediately sent me a message: ‘You’ve discovered the secret of Avatar! Go see it!’ The similarities are quite striking. I don’t think there is much spirit in the networks we’ve seen here. It might be only about energy. But there are connections,” Nielsen said.