WASHINGTON: A team of researchers from Louisiana State and Montana universities will search for "immortal cells" beneath the Antarctic ice sheets.

Antarctica is home to the largest body of ice on Earth, but prior to approximately 10 years ago, no one thought that life could exist beneath the ice sheets, which can be more than two miles thick at some places.

Then, a study by Brent Christner, assistant professor of biological sciences at LSU revealed the existence of viable microbes in ancient ice cores and sub-glacial environments in the icy continent.

This coupled with the realization that large quantities of liquid water exist beneath the Antarctic ice sheet have changed the way biologists now view life in Antarctica.

"More than 150 lakes have been discovered underneath nearly two-and-a-half miles of ice in Antarctica and most of these bodies of water have likely been covered by ice for at least 15 million years. The environmental conditions in the deep cold biosphere are unlike anything on the Earth's surface and this represents one of the most extreme habitats for life on the planet," said Christner.

Christner also offered two possible explanations of how these microbes could survive frozen for millennia. A timeframe of up to one million years is required for microbes in the atmosphere to be transported through the ice sheet and enter an Antarctic sub-glacial lake.

Christner said, firstly, the microbes might be dormant in the ice and possess "very effective repair mechanisms that are initiated when the cells are introduced to a growth situation".

"Given enough time, dormant cells - without active DNA repair mechanisms - would eventually incur a lethal level of radiation-induced damage from natural background sources in the ice," he said.

The other possibility, he said, could be that the microbes might have stayed metabolically active while remaining entrapped in the ice, giving them the ability to repair damage as it occurred.

"If this is the case, these microbes may be essentially immortal when frozen - that is, if a continuous energy supply was available," Christner said, adding, that lab research has shown that glacier microbes are capable of metabolic activity when frozen down to -20 degrees Celsius.

"Our experiments have revealed the potential for microbes to metabolize under frozen conditions, but we still lack the 'smoking gun', which proves this occurs in nature. We are now taking what we learned in the lab at LSU and using it to design experiments that address this question in real Antarctic ice samples," said Christner.

Now, in collaboration with research colleagues from Montana State University, Christner and two members of his laboratory will deploy to Antarctica in October 2007.

Shawn Doyle, LSU senior and microbiology major, will accompany Christner, staying through January 2008.