Daily Archives: March 23, 2009

Evidence of Ancient Oxygenic Photosynthesis Discovered

Simple, photosynthesising life forms created an excess of oxygen in the oceans 700 million years earlier than previous estimates suggest, an international team of geologists claim.

The research, published today in the journal Nature Geosciences, pushes back the earliest appearance of photosynthesising organisms from 2.7 to 3.46 billion years ago.


The orientation and nature of the grains of haematite also show that it precipitated directly from the seawater, rather than forming later from other processes, such as the movement of groundwater, they add.

“These data strongly suggest that oxygenic photoautotrophs flourished in the photic zone of the 3.46 [billion-year-old] oceans and supplied molecular oxygen to the deep water,” the researchers write.


“Recently accumulated massive amounts of geochemical and biochemical data can be better explained by a theory postulating the emergence of oxygenic photosynthesis and the development of a fully oxygenated atmosphere in the very early evolutionary stage,” says Ohmoto.