The oldest compelling fossil evidence for cellular life has been discovered on a 3.43-billion-year-old beach in western Australia. Grains of sand there 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.
