But the arrival of the research team brought one substance into the underground world that, though vital to human survival, proved fatal to the microbes -- air from the surface.
"These critters seems to have a real problem with being exposed to oxygen," Onstott said. "We can't seem to keep them alive after we sample them. But because this environment is so much like the early Earth, it gives us a handle on what kind of creatures might have existed before we had an oxygen atmosphere."
Onstott said that many hundreds of millions of years ago, some of the first bacteria on the planet may have thrived in similar conditions, and that the newly discovered microbes could shed light on research into the origins of life on Earth.
"These bacteria are probably close to the base of the tree for the bacterial domain of life," he said. "They might be genealogically quite ancient. To find out, we will need to compare them to other organisms such as Firmicutes and other such heat-loving creatures from deep sea vents or hot springs."
The research team is building a small laboratory 3.8 kilometers beneath the surface in the Witwatersrand region of South Africa to conduct further study of the newly discovered ecosystem, said Onstott, who hopes the findings will be of use when future space probes are sent to seek life on other planets.
"A big question for me is, how do these creatures sustain themselves?" Onstott said. "Has this one strain of bacteria evolved to possess all the characteristics it needs to survive on its own, or are they working with other species of bacteria? I'm sure they will have more surprises for us, and they may show us one day how and where to look for microbes elsewhere."
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Contact: Chad Boutin
cboutin@princeton.edu
609-258-5729
Princeton University
20-Oct-2006