Illustration for article titled The seafloor is home to a vast electrical network created by bacteria

It sounds a little bit like one of the subplots in Avatar, where we discover that the moon Pandora possesses a kind of mega-consciousness created by bio-electrical circuitry. But this is actually real. Two years ago, researchers discovered a strange electro-chemical signature in the sludge at the bottom of Aarhus Bay in Denmark. Now, they've discovered what was causing it: a vast network of bacteria that form electrical connections with each other, almost like nerve cells in the brain.


Above, you can see what you might call tiny electrical wires that connect each bacterial cell, under an electron microscope. The wires are blue, and they are running through a piece of sediment, or sand from the seafloor.

Over at Wired Science, Brandon Keim explains:

The bacteria were first detected in 2010 by researchers perplexed at chemical fluctuations in sediments from the bottom of Aarhus Bay . . . Almost instantaneously linking changing oxygen levels in water with reactions in mud nearly an inch below, the fluctuations occurred too fast to be explained by chemistry.

Only an electrical signal made sense — but no known bacteria could transmit electricity across such comparatively vast distances. Were bacteria the size of humans, the signals would be making a journey 12 miles long.

Now the mysterious bacteria have been identified. They belong to a microbial family called Desulfobulbaceae, though they share just 92 percent of their genes with any previously known member of that family. They deserve to be considered a new genus, the study of which could open a new scientific frontier for understanding the interface of biology, geology and chemistry across the undersea world.


Even more incredible, it turns out these bacteria are found all over the world, their tiny electrical cables woven deeply into the mud of the ocean bottom. Keim writes that the scientists found "a full half-mile of Desulfobulbacea cable" in one teaspoonful of mud.

Illustration for article titled The seafloor is home to a vast electrical network created by bacteria

In other words, the entire ocean bed may be electrified in the same way our nervous systems are. They're networks of individual cells connected by electro-chemical signals — essentially they are an enormous multi-cellular organism. These bacteria "breathe" by absorbing oxygen and hydrogen sulfide, emitting water as a byproduct. They might be serving as a vast water purification system on the ocean bottom, or they might be part of a geological process that's a lot more complex. We also have no way of knowing how other sea creatures are interacting with this giant electrical grid organism.

What matters here is that we've just discovered a new kind of life that is not only ubiquitous, but also engaging in electro-chemical processes throughout the oceans. There's no evidence that this life form is "thinking" in any way that we'd recognize, but it certainly sounds like the perfect opening to a science fiction story.


Read more about this bacterial network, and see more amazing pictures, in Wired. Read the scientists' paper in Nature. Images via Nils Risgaard-Petersen; schematic via Nature

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