A study of molecules in the fossil record has pinpointed the rise of algae on Earth:
A planetary takeover by ocean-dwelling algae 650 million years ago was the kick that transformed life on Earth. That's what geochemists argue in Nature this week [DOI: 10.1038/nature23457] [DX], on the basis of invisibly small traces of biomolecules dug up from beneath the Australian desert.
The molecules mark an explosion in the quantity of algae in the oceans. This in turn fuelled a change in the food web that allowed the first microscopic animals to evolve, the authors suggest. "This is one the most profound ecological and evolutionary transitions in Earth's history," lead researcher Jochen Brocks told the BBC's Science in Action programme.
(Score: 3, Informative) by Anonymous Coward on Friday August 18 2017, @04:50PM
Pretty sure this is a different thing, the O2 catastrophe happened 2.5–2.4 billion years ago according to wikipedia.
This event is much more recent.