July 6, 2000 -- In a finding that may extend the known limits of life on Earth, researchers supported by the National Science Foundation (NSF) have discovered evidence that microbes may be able to survive the heavy doses of ultraviolet radiation and the extreme cold and darkness of the South Pole.
The team's findings, published in Applied and Environmental Microbiology, the journal of the American Society for Microbiology, indicate that a population of active bacteria, some of which have DNA sequences that align closely with species in the genus Deinococcus, exists at the South Pole in the austral summer. A similar species lives elsewhere in Antarctica, but the discovery of microbes at the Pole may mean that the bacteria have become uniquely adapted to the extreme conditions there, including a scarcity of liquid water.
A species in the genus Deinococcus was first discovered in cans of irradiated meat in the 1950's, and is able to withstand extreme dryness and large doses of radiation. It is possible that the related bacteria from the South Pole may also possess these characteristics.
"While we expected to find some bacteria in the South Pole snow, we were surprised that they were metabolically active and synthesizing DNA and protein at local ambient temperatures of -12 to -17 Celsius (10.4 to 1.4 degrees Fahrenheit)," said Edward J. Carpenter, of the State University of New York at Stony Brook, who headed the research team. "Before attempting to publish the results, we wanted to be certain that the data were correct and were able to duplicate the observations in a second field season during January 2000."
Antarctica was once part of a supercontinent called Gondwanaland and drifted into its present position only about 60 million years ago. Deinococcus, however, is thought to be one of the earlier branches in the bacterial tree, and is much older than Antarctica in its present location. It is therefore unlikely that it evolve
Contact: Michelle Edwards
National Science Foundation