Oldest fossils show early life was a beach
THE oldest compelling fossil evidence for cellular life has been discovered on a 3.43-billion-year-old beach in western Australia. Its grains of sand provided a home for cells that dined on sulphur in a largely oxygen-free world.
The rounded, elongated and hollow tubular cells - probably bacteria - were found to have clumped together, formed chains and coated sand grains. Similar sulphur-processing bacteria are alive today, forming stagnant black layers beneath the surface of sandy beaches.
The remarkably well-preserved three-dimensional microbes could help resolve a fierce and long-running debate about what is the oldest known fossil - or at least add to it. The current record is held by fossils that are 35 million years older than the present find in nearby deposits known as the Apex chert. But in 2002 a team led by Martin Brasier of the University of Oxford showed that the bacteria-like shapes could have formed in a mineral process that had nothing to do with life.