THE discovery of ancient fossils in Australia has strengthened the evidence
that life began in 鈥渂lack smokers鈥� deep beneath the sea.
These hydrothermal vents would have been ideal for nurturing life, some
researchers have argued, as they provided a constant supply of nutrients and
were protected from the ultraviolet radiation and asteroids bombarding the
planet鈥檚 surface. However, only relatively recent fossils have been found in
rocks associated with vents. Now Birger Rasmussen of the University of Western
Australia, Perth, has found the imprints of what could be thread-like
microorganisms in metal sulphide deposits dating back 3 billion years
(Nature, vol 405, p 676). The ancient microbes probably thrived in the
absence of light or oxygen in scalding temperatures of up to 110掳C, he
suggests.