Earthly oxygen

Isotope studies by Linda Godfrey and Paul Falkowski of Rutgers University have revealed new details about the ebb and flow of oxygen levels in the Earth's atmosphere and oceans. The work reaffirms other evidence that oxygen-producing bacteria, which presumably caused the first spike of two spikes in oxygen levels were present in the oceans long before the spike occurred. Independent work by Robert Frei and colleagues at the University of Copenhagen provides a new isotope technique that could home in on even finer detail of the transition from the anoxic to the oxygenated world we see today.