Holds implications for search for life in the solar system
Two separate investigations of ice drilled at Lake Vostok, a suspected body of subglacial water deep in the Antarctic interior, indicate that bacteria may live thousands of meters below the ice sheet. The findings by two National Science Foundation-funded researchers are scheduled for publication in the Dec. 10 issue of Science.
Two research teams, led by David M. Karl from the University of Hawaii and John C. Priscu of Montana State University, examined fragments of ice taken from roughly 3,600 meters (11,700 feet) below the surface -- about 120 meters (393 feet) above the interface of ice and suspected water. Both teams found bacteria in "accreted" ice, or ice believed to be refrozen lake water.
The teams conclude that a potentially large and diverse population of bacteria may be present in the lake. If so, this bacteria answers an intriguing scientific question about whether an extremely cold, dark environment which is cut off from a ready supply of nutrients can support life.
The DNA analysis by Priscu's team indicates that although the bacteria have been isolated for millions of years, they are biologically similar to known organisms. "Our research shows us that the microbial world has few limits on our planet," said Priscu. He added that Lake Vostok "is one of the last unexplored oases for life" on Earth.
The teams also conclude microbes could thrive in other, similarly hostile, places in the solar system. Lake Vostok is thought to be an analog to Europa, a frozen moon of Jupiter. Priscu notes in his paper that the Galileo spacecraft found evidence that liquid water exists under an icy crust on the Jovian moon. "Similar to ice above Lake Vostok, this ice may retain evidence for any life, if present, in the Europan ocean," he writes.