Scientists revive eight million year old primitive life forms
20 February 2004
Scientists have revived primitive life forms retrieved from frozen ground in the Antarctic and believed to be up to eight million years old.
The revival of ancient colonies of bacteria was a significant step in helping develop new methods for investigating whether alien life has existed, or still exists, on other planets, University of Otago geologist Dr Gary Wilson said this week.
Dr Wilson has helped lead a 24-member team which has worked on the nine-year project.
With Imre Friedmann from Nasa and David Gilichinsky from the Russian Academy of Sciences, Dr Wilson extracted dormant bacteria from sedimentary layers at several sites beneath frozen ground estimated to be between five and eight million years old.
Ensuring the bacteria was not contaminated by other organisms, they placed them in freezers and shipped them to the United States – where Dr Wilson works at Ohio State University – and later to Russia.
To revive the bacteria, collected from soil with a temperature of about -27degC, the scientists placed samples in dishes and raised the temperature to varying levels. At temperatures above 0degC, the bacteria began to revive and grow, Dr Wilson said.
That it could be revived showed the bacteria was not dead, but had been dormant since a time when conditions were very different in the Antarctic.
"The colony was not active, but they may have just been shut down waiting for conditions to come right again," he said.
"Clearly the Antarctic was more conducive to life at an earlier time when the conditions in the soil were more favourable."
Though the cells are very primitive life forms, the length of time they had been able to survive was significant for further study of other inhospitable environments such as Mars, Dr Wilson said.
"If we had discovered they could only survive for 100 years it would be different, but because we've found they survived many millions of years, the chance of finding life on other planets (where the environments have changed) is greater."
"If Antarctica is a reasonable analogue of Mars, then we can learn something about where to look for life and ask if things there are still viable given the conditions we find."
Nasa had long shown an interest in the Antarctic because of the potential for comparisons with Mars.
Dr Wilson and his colleagues found the viable bacteria were in greater quantity deep beneath the Antarctic surface, where there was also evidence of the by-products of life including chlorophyll, enzymes and hydrocarbon gases.
On Mars, therefore, it might be more productive to look for similar signs deep beneath the planet's surface, when trying to determine if life existed there.
Asked if he believed life could have existed on other planets, Dr Wilson was quick to answer.
"I believe it, but I can't prove it."
