Microbes Discovered in Antarctic Ice.

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Within the windswept lake ice in Antarctica--the world's most inhospitable landscape--scientists have discovered teeming microbe colonies that use sunlight filtering through the ice to activate and sustain life when the South Pole tilts toward the sun each year. The researchers have found diverse microorganisms throughout the frozen lake water, supported by the key life-sustaining processes photosynthesis and atmospheric nitrogen fixation. Previously, most investigators thought little or no biological activity could occur within the ice itself.

"This discovery, which is quite exciting, shows how life could exist on other planets," says Hans Paerl, Kenan Professor of Marine Sciences, University of North Carolina at Chapel Hill. "Solar heating allows the water to melt around soil particles that have blown over the ice and have been buried in it. Microbes covering them can then spring to life within an hour under certain conditions, even though they are still embedded deep in the ice." This results in living layers within the ice that distinctly show years, like growth rings in a tree trunk.

"A key to the ability of microbes to live under these extreme conditions is the presence of liquid water, which is formed by solar...