'Dig deep to find alien life'

Humble E. coli can survive enormous pressures

By BBC News Online's Ivan Noble

A study in the US suggests far more of our Solar System may be capable of sustaining basic life than previously thought.

We should be looking beneath the surface of planets

James Scott
Carnegie Institution

Scientists have known for a while about extremophiles, the specially adapted organisms that can survive around volcanic vents deep in the ocean or in the ice sheets of the Antarctic.

But now it seems that even humble E. coli of stomach bug fame is capable of amazing feats of survival, withstanding up to 16,000 times the pressure it normally faces at sea level.

"The take home lesson is that we should be looking beneath the surface of planets, under the polar caps of Mars or beneath the surface of the Jovian moons," James Scott of the Carnegie Institution in Washington told BBC News Online.

Diamond test

He and his colleague Anurag Sharma used a tool commonly employed by geologists to study what happens at high pressure deep beneath the Earth's surface.

They took a diamond anvil cell and adapted it to host bacteria.

We can't say that they're thriving but we can see that they are surviving

James Scott
Carnegie Institution

They found that even at the kind of pressures that exist 50 kilometres (30 miles) below the Earth's surface, E. coli can survive.

"We can't say that they're thriving but we can see that they are surviving. They're moving around and they're metabolising," Dr Scott said.

"What all this says to us is that pressure is not going to be a key detriment to finding life," he added.

The question now is why the bacteria can accomplish this incredible feat. Dr Scott says he and his colleagues have some theories but still need to put them to the test.

"We will answer that question," he said. The Carnegie team describe their work in the journal Science.