It proved a long, arduous journey for Hoover and his colleagues to complete the process of identifying a unique new life form. For the life form itself, a new bacterium dubbed Carnobacterium pleistocenium, the journey to discovery took much longer - some 32,000 years.

The bacterium - the first fully described, validated species ever found alive in ancient ice - is NASA's latest discovery of an "extremophile."

Extremophiles are hardy life forms that exist and flourish in conditions hostile to most known organisms, from the potentially toxic chemical levels of salt-choked lakes and alkaline deserts to the extreme heat of deep-sea volcanoes.

NASA and its partner organizations study the potential for life in such extreme zones to help prepare robotic probes and, eventually, human explorers to search other worlds for signs of life.

This search is a key element of the Vision for Space Exploration, the ambitious effort to return Americans to the Moon and to conduct robotic and human exploration of Mars and other worlds in our Solar System, which might conceal life forms unimaginable to us - thriving in conditions few Earth species could tolerate.

In 1999 and 2000, Hoover, a researcher at NASA's Marshall Space Flight Center in Huntsville, Ala., time-traveled back to the Pleistocene via the

U.S. Army's Cold Regions Research and Engineering Laboratory, or "CRREL tunnel."

The research site near Fox, Alaska, just north of Fairbanks, was carved by the Army Corps of Engineers in the mid-1960s to enable geologists and other scientists to study permafrost - the mix of permanently frozen ice, soil and rock - in preparation for construction in the early 1970s of the Trans-Alaska Oil Pipeline.

Hoover initially went to the CRREL tunnel in search of "psychrophiles" - organisms that live only at extremely low temperatures. Hoover initially suspected the samples he collected there, from ice more than 30 millennia old, were diatoms, or microscopic, golden-brown algae.

But closer study at the nearby University of Alaska revealed not diatoms but something much more interesting - an assortment of bacterial cells, many of which came to life as soon as the ice thawed.

Hoover and his collaborator, microbiologist Dr. Elena Pikuta of the University of Alabama in Huntsville, studied the samples at the National Space Science and Technology Center, the research consortium operated by NASA and Alabama universities. They found the samples contained anaerobic bacteria that grew on sugars and proteins in total absence of oxygen. The bacteria had frozen near the end of the Pleistocene Age, which extended from about 1.8 million years ago to just 11,000 years ago - and earned the new organism its name.

Further testing revealed the organism was not a psychrophile at all, but a "psychrotolerant" - not an organism that thrives only at very cold temperatures, but one capable of enduring deep cold that resumes normal activity when temperatures rise.

Community Email This Article Comment On This Article Related Links Cold Regions Research and Engineering Laboratory National Space Science and Technology Center SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Nuclear Space Technology at Space-Travel.com Memory Foam Mattress Review SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News EXO LIFE Studying Slime Moffett Field (SPX) Nov 02, 2004 Penny Boston is one of the leaders of the SLIME team - that's Subsurface Life in Mineral Environments. She studies bizarre microorganisms that live, often under extreme conditions, in subterranean caves. At the recent NASA symposium "Risk and Exploration: Earth, Sea and the Stars," in Monterey, California, she talked about the relevance of her work below ground on Earth to the search for life on other worlds.