Oxygen's ups and downs in early atmosphere and ocean
Tuesday, October 23, 2012 - 14:00
in Earth & Climate
Geochemists challenge the simple notion of an up-only trend for early oxygen on Earth, and provides the first compelling direct evidence for a major drop in oxygen after the gas's first rise. This drop, they say, may have ushered in more than a billion years that were marked by a return to low-oxygen concentrations at Earth's surface, including the likelihood of an oxygen-free deep ocean.