Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, February 26, 1995 TAG: 9502280032
SECTION: NATIONAL/INTERNATIONAL PAGE: A1 EDITION: METRO
SOURCE: PETER JAMES SPIELMANN ASSOCIATED PRESS
DATELINE: TAYLOR VALLEY, ANTARCTICA LENGTH: Medium
Antarctica's dry valleys are the coldest, most brutal deserts on Earth, yet even here at the limits of survivability, there is life.
Conditions in the Taylor Valley and the other dry valleys are so relentlessly harsh that they are more Mars-like than any other place on Earth - which is why NASA is co-funding research into the living rocks there.
The clue that led NASA to use the dry valleys east of the U.S. McMurdo Station as a model for possible life on Mars was found more than 20 years ago, in a dead man's rock sample bag.
By 1973, the Viking spacecraft had been designed to look for traces of life in the soil near their landing sites, and they were launched two years later.
But Imre Friedmann, a biologist and now director of the Polar Desert Research Center at Florida State University in Tallahassee, thought that was the wrong approach.
If life was to be found on Mars, he argued, it would not be in soil that was baked or frozen to sterility. More likely, it would exist as micro-organisms that retreated into porous rocks themselves.
``Life is so harsh that micro-organisms go either inside the rocks or under them,'' he said. ``They are living at the very edge of life.''
Friedmann had found such organisms - bacteria and lichens called cryptoendoliths - first in the Negev Desert of his native Israel, then high in the Alps, and in deserts in Mongolia and the American Southwest.
Friedmann believed that if similar organisms could be found in Antarctica's dry valleys, they would be the sort of life form NASA should be looking for on Mars, an equally hostile environment.
Scientists believe conditions on Earth and Mars were similar 3.5 billion to 3.8 billion years ago; then Mars became colder, drier and apparently sterile. If there was Martian life, it probably never evolved beyond micro-organisms, and then died out.
``We can use Antarctica to reconstruct the processes before the extinction of life on Mars,'' Friedmann contended.
Friedmann couldn't persuade the U.S. science bureaucracy to fund a trip to Antarctica to look for cryptoendoliths; he was ``laughed out,'' he recalled. But a friend, Wolf Vishniac, was heading there in 1973 to study soil samples.
Friedmann asked Vishniac, a microbiologist at the University of Rochester who was part of the Viking lander planning team, to look for rocks like those he had found sheltering micro-organisms in the Negev.
Tragedy ensued.
Vishniac died in a mountain-climbing accident in Antarctica. Friedmann grieved for his friend, and was crushed by the loss of his only chance to prove his theory about the possibility of life in the dry valleys.
``A few months later I got a letter from his widow,'' microbiologist Helen Vishniac, he said. She told him she had found ``a rock bag with your name on it.''
Friedmann took the samples and found rock-dwelling bacteria inside them, a discovery that persuaded the National Science Foundation to support his Antarctic research beginning in 1974.
Now working on conjunction with Chris McKay of NASA's Ames Research Center, Friedmann and his crew have found about 30 species of bacteria maintaining a fragile toehold on life in the dry valleys.
The Antarctic cryptoendoliths eke out an existence in temperatures that edge just over freezing in summer, but drop to -50 Fahrenheit in winter.
They are fragile but tenacious. Friedmann's sample colonies are estimated to be 10,000 years old - biology on the time scale of geology.
NASA is interested in the fact that these micro-organisms cause physical changes in their rocks. If such cryptoendoliths ever lived on Mars, a properly designed spacecraft should be able to find evidence that they were there - their fossils and the chemical changes they wrought in the rocks.
NASA plans to send the Mars Pathfinder spacecraft to the red planet, aiming for a 1997 landing. The Pathfinder will look for promising samples of soil and rock.
``Very basic questions could be answered with just a few molecules,'' such as whether life evolved the same way on both Earth and Mars, and what DNA or other genetic codes may be on Mars, Friedmann said.
by CNB