Eventually, however, terrestrial red and green
algae and the first lichens developed on land and the final big rise in oxygen may have been caused by the «greening of the continents from around 800 million years ago,» when these
simple early lifeforms on land steadily spread and broke down rocks that sustained a higher rate of erosion and led to the release of more nutrients into the oceans that stimulated even more photosynthesis by more newly evolved
algae as well
as older cyanobacteria (Nick Lane, New Scientist, February 10, 2010).