Stepwise Earth oxygenation is an inherent property of global biogeochemical cycling

Abstract

Stepping to an internal beat What caused the stepwise nature of the rise of molecular oxygen in Earth's atmosphere since it appeared in large quantities more than 2 billion years ago? Alcott et al. argue that a set of internal feedbacks involving the global phosphorus, carbon, and oxygen cycles, not individual external forces, could be responsible. Their model, which depends only on a gradual shift from reducing to oxidizing surface conditions over time, produces the same three-step pattern observed in the geological record. Science , this issue p. 1333