Nature, Vol.382, No.6587, 127-132, 1996
Late Proterozoic Rise in Atmospheric Oxygen Concentration Inferred from Phylogenetic and Sulfur-Isotope Studies
The evolution of non-photosynthetic sulphide-oxidizing bacteria was contemporaneous with a large shift in the isotopic composition of biogenic sedimentary sulphides between 0.64 and 1.05 billion years ago. Both events were probably driven by a vise in atmospheric oxygen concentrations to greater than 5-18% of present levels-a change that may also have triggered the evolution of animals.