Life is found in deepest layer of Earth's crust

The New Scientist ^ | 18 November 2010 | Michael Marshall

[Fractal Trader]

IT'S crawling with life down there. A remote expedition to the deepest layer of the Earth's oceanic crust has revealed a new ecosystem living over a kilometre beneath our feet. It is the first time that life has been found in the crust's deepest layer, and an analysis of the new biosphere suggests life could exist lower still.

On a hypothetical journey to the centre of the Earth starting at the sea floor, you would travel through sediment, a layer of basalt, and then hit the gabbroic layer, which lies directly above the mantle. Drilling expeditions have reached this layer before, but as the basalt is difficult to pierce it happens rarely.

To facilitate the task, the Integrated Ocean Drilling Programme set its sights on the Atlantis Massif. [SNIP] A team led by Stephen Giovannoni of Oregon State University in Corvallis drilled down to 1391 metres, where temperatures reach 102 °C.

There, they found communities of bacteria that were sparse but widespread. The type of bacteria they found came as a surprise to Giovannoni, who has previously found micro-organisms living in the basalt layer. "We expected to find similar organisms in the deeper layer," he says. "But actually it was very different."

One key difference was that archaea were absent in the gabbroic layer. Also, genetic analysis revealed that unlike their upstairs neighbours, many of the gabbroic bugs had evolved to feed off hydrocarbons like methane and benzene. [SNIP]

"This deep biosphere is a very important discovery," says Rolf Pedersen of the University of Bergen, Norway. He points out that the reactions that produce oil and gas abiotically inside the crust could happen in the mantle, meaning life may be thriving deeper yet.

[SunkenCiv]

from the FRchives:

• Could 'Goldilocks' planet be just right for life?
• Hostile volcanic lake teems with life: Microbes thriving in salty, alkali waters containing...
• Lava Cave Minerals Actually Microbe Poop [clues in the search for life on Mars and beyond]
• At 2.8 km down, a 1-of-a-kind microorganism lives all alone [descende, Audax viator ...]
• Deep Under the Sea, Boiling Founts of Life Itself
• Research Finds Life 1000 Feet Beneath Ocean Floor