29 June 1998

Antarctic Bacteria Suggests Life On Mars Possible

With less than four inches of precipitation per year and an average annual temperature of 68 degrees below zero, the McMurdo Dry Valleys of Antarctica rate among the coldest, driest and most God-forsaken deserts on Earth. Yet in liquid pockets six feet into solid ice, scientists have discovered thriving bacterial colonies.

The astonishing finding, reported in the June 26 issue of Science, may provide insights for possible life forms elsewhere in our solar system. In particular, conditions in the Antarctic deserts are said to compare with those on Mars and Europa.

"This is a very barren environment with virtually nothing we usually associate with living organisms," says Stephen Giovannoni, associate professor of microbiology at Oregon State University and key player in the discovery. "But these photosynthetic cyanobacteria are alive, self-sufficient, and growing. They're able to live through the harsh freeze-thaw cycle of the seasons, fix nitrogen and release oxygen as they make carbohydrates from water and carbon dioxide. They have their own little world we knew nothing about."

While the nutritional requirements of the bacteria are minimal (a little light, water, carbon dioxide, phosphate, nitrate and other minerals), the primitive life processes are said to be similar to those that first formed the oxygen-rich atmosphere of Earth and made higher life forms possible.

"It's been suggested that Mars is too dry and cold for life to exist," says Giovannoni. "But it's also known that both Mars and Europa have frozen water on or near their surfaces. We speculate that in conditions similar to those we observed in Antarctica, it would be a distinct possibility that similar life forms exist on Mars or Europa."