CORVALLIS, Ore. - Bacterial colonies are thriving underneath ice on one of the coldest, driest deserts on Earth, researchers have discovered, in conditions that might compare to those on Mars or Europa and provide insights for life forms that could be found elsewhere in our solar system.
The study will be reported Friday in the journal Science.
This study was conducted on ice-covered lakes in the McMurdo Dry Valleys of Antarctica, which has an average annual temperature about 68 degrees below zero and gets less than four inches of precipitation a year.
But in that frigid, arid environment, scientists at Oregon State University and four other institutions found liquid water pockets embedded about six feet deep in solid ice, where a combination of sediments, water and solar radiation during long summer days supports a viable population of bacteria.
"This is a very barren environment with virtually nothing we usually associate with living organisms," said Stephen Giovannoni, an associate professor of microbiology at Oregon State University. "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 there we knew nothing about."
The nutritional requirements of these life forms are minimal, Giovannoni said - a little light, water, carbon dioxide, phosphate, nitrate and other minerals. But in fact the primitive life processes they are undertaking are quite similar to those that first formed the oxygen-rich atmosphere of Earth and made higher life forms possible.
And in the study, the researchers cite two locations where they feel conditions may exist that are similar to those found in barren Antarctica - Mars, and a large moon of Jupiter, Europa.