LIFE may have colonised the land more than a billion years earlier than
thought.
Layers of 2.6-billion-year-old soil from a site in South Africa have been
found to contain unusual levels of organic compounds. Chemical analysis
indicates that the compounds came from photosynthetic cyanobacteria, Yumiko
Watanabe of Pennsylvania State University reports in Nature (vol 408, p
574). He suggests that mats of microbes about a centimetre thick grew on
clay-rich soil during rainy seasons.
Previously, 1.2-billion-year-old fossils from Arizona were the oldest
evidence of microbes on land.
