Large Bacterial Population Colonized Land 2.75 Billion Years Ago
ScienceDaily (Sep. 24, 2012) — There is evidence that some
microbial life had migrated from Earth's oceans to land by 2.75
billion years ago, though many scientists believe such land-
based life was limited because the ozone layer that shields
against ultraviolet radiation did not form until hundreds of
millions years later. But new research from the University of
Washington suggests that early microbes might have been
widespread on land, producing oxygen and weathering pyrite, an
iron sulfide mineral, which released sulfur and molybdenum into
the oceans. Sulfur could have been released into sea water by
other processes, including volcanic activity. But evidence that
molybdenum was being released at the same time suggests that
both substances were being liberated as bacteria slowly
disintegrated continental rocks. Proud Canadian, Enlightened
Atheist, Gaming God.