Ocean Bacteria Act As ‘Superorganism’
Photo via flickr by komehachi888
Aarhus University scientists have found that sulphur-eating bacteria that live in muddy sediments beneath the sea floor may be connected by a network of microbial nanowires that could shuttle electrons back and forth, allowing communities of bacteria to act as one super-organism. The interconnected ecosystem of the bacteria are compared to the Na’vi people of Pandora in the movie Avatar, where they plug themselves into a network that links all elements of the biosphere, from phosphorescent plants to pterodactyl-like birds.
“The discovery has been almost magic,” says Lars Peter Nielsen of Aarhus University. “It goes against everything we have learned so far. Micro-organisms can live in electric symbiosis across great distances. Our understanding of what their life is like, what they can and can’t do—these are all things we have to think of in a different way now.”
Nielsen and his team took samples of bacteria-laced sediment from the sea floor close to Aarhus. In the lab, they first removed and then replaced the oxygen in the seawater above the samples. To their surprise, measurements of hydrogen sulphide revealed that bacteria several centimetres from the surface started breaking down the gas long before the reintroduced oxygen had diffused down to them.
Nielsen believes a network of conductive protein wires between the bacteria makes this possible, allowing the oxidation reaction to happen remotely from the oxygen that sustains it. The wires transport electrons from bacteria in deeper, oxygen-poor sediments to bacteria in oxygen-rich mud near the surface. There, they are offloaded onto the oxygen, completing the reaction. Nielsen calls the process “electrical symbiosis.”