WASHINGTON (AP) - What may be the oldest complete fossil on Earth paints a
smelly but colorful picture of our microbial ancestors from nearly 3.5
billion years ago.
The fossil is the remains of what once was a purple-and-green slimy, smelly
mat of single cell microbes that worked, lived and even communicated
together in what is an awful lot like a prehistoric microscopic society.
Nora Noffke of Old Dominion University in Virginia found the remnants of
this life in sandstone rock in western Australia.
This is likely an ancestor of ours, researchers said.
This tiny fossilized mat, about one-third of an inch thick, would be about
300 million years older than previous complete ancient fossils and about the
same age as less complete and still debatable fossils, said study co-author
Robert Hazen, a mineralogist at the Carnegie Institution of Science in
Washington. He said life on the mat probably had turned sunlight into
energy, but unlike life now, probably producing “horribly smelly” sulfur
instead of oxygen.
The research was published online last week in the journal Astrobiology.
NASA astrobiologist Abigail Allwood, who found slightly younger fossils a
few years ago, said it is challenging to prove the fossil contained life.
But Hazen said they used dozens of criteria to show that the microscopic
features fit with what science knows about ancient life.
If you had walked the Australian beaches of 3.5 billion years ago you would
see this “slimy mass of purple or brown fibers emitting this stench of
sulfur compounds but living very happily,” Hazen said. “This is not a place
you would want to go to on your summer vacation.”