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PALEONTOLOGY ARTICLE

Signs of microbial life found in volcanic rock
by MIKE BALDWIN

06.21.00--Geologists have found apparent fossil evidence of microbial life in scalding hot deep-ocean vent systems on the very young Earth, 2.7 billion years earlier than previously known. The signs of such ancient single-celled organisms -- thread-like filaments etched in volcanic rock some 3.2 billion years old -- bolster a theory favored by many biologists, based on genetic studies, that the first life on Earth arose in such a sunless, toxic and hot environment.

"The cradle of life may have been a sulphurous, subterranean inferno, not unlike a medieval vision of hell," said Birger Rasmussen, of the University of Western Australia, who describes his discovery in today's issue of the journal Nature.

In recent decades, scientists have learned that life can thrive in extreme environments previously thought to be lethal. On Earth today, deep ocean hydrothermal vent systems are known to sustain various creatures, including diverse bacterial communities. But microfossils of any kind in such ancient deposits are extremely rare and, up to now, none like these had been found in rock more than about half a billion years old.

Paleobiologist Andrew Knoll, of Harvard, said Rasmussen's find represents a rare and welcome insight into a 2 billion year stretch of Earth's biological history that remains cloaked in mystery.

The first murky chemical sign of life anywhere on Earth dates to 3.8 billion years ago, he noted, and by 3.5 billion years ago, the record indicates that primitive biology of some sort "was a going concern."

Rasmussen's fossils appear to be the imprints left by strings of single-celled heat-loving organizms a thousandth of a millimeter in diameter and a tenth of a millimeter in length. He found the stringy formations unexpectedly while studying core samples of rock drilled from a 3.2-billion-year-old metal sulphide deposit in the Pilbara region of northwestern Australia.

The information above was taken from The Washington Post via The Commercial Appeal, Memphis, TN June 8, 2000.