Life in the Inferno: Researchers Identify Factors that Determine Where Microorganisms Can Survive in the Hellish World Deep Underground

Even Dante would blanch at the conditions kilometers below the earth's surface. Temperatures climb past 100 degrees Celsius, pressures hundreds of times greater than atmospheric pressure bear down, and space is so tight even microorganisms can barely budge.

Yet, even there life persists. Now subsurface scientists have begun to identify the factors that determine why microorganisms survive deep underground in some places, but not others, report researchers from the Department of Energy's Idaho National Engineering and Environmental Laboratory and Princeton University. The INEEL specializes in subsurface science as part of its environmental mission.

High temperatures ensure nothing can live too far below the earth's surface. But pressure, the availability of water, the porosity of the surrounding rock and the flow of chemical nutrients also limit where extremophiles--microorganisms that relish harsh conditions--can exist.

As recently as the 1980s most microbiologists thought nothing could survive far below the soil layer. They now know extremophiles live embedded in rock hundreds of meters below dry land, in deep ocean sediments and in fissures crisscrossing the ocean floor.

"We're at the point of recognizing that microorganisms have remarkable abilities to colonize these environments and trying to understand the parameters that control that colonization," said INEEL microbiologist Rick Colwell, who presented a synthesis of recent findings in the Biogeoscience: Deep Biospheres: Where and How? poster session today at the American Geophysical Society meeting in San Francisco.

A better understanding of how extremophiles survive deep underground may shed light on how life endured the earth's violent youth, or show scientists where to look for life on other planets, said Pri
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Contact: Mary Beckman
beckmt@inel.gov
208-526-0061
DOE/Idaho National Laboratory
15-Dec-1999