Earth oxygen existed 2.5 billion years ago

TEMPE, Ariz., Oct. 1 (UPI) -- A study funded by the U.S. space agency suggested oxygen existed in Earth's atmosphere much earlier than thought.

Two separate teams of astrobiologists found evidence of oxygen in the Earth's oceans and atmosphere approximately 2.5 billion years ago by analyzing a nearly 1-mile-long drill core from Western Australia.

"We seem to have captured a piece of time during which the amount of oxygen was actually changing -- caught in the act, as it were," said Arizona State University-Tempe Associate Professor Ariel Anbar, who led one of the research teams.

The other research group was led by Alan Kaufman of the University of Maryland.

"Studying the dynamics that gave rise to the presence of oxygen in Earth's atmosphere deepens our appreciation of the complex interaction between biology and geochemistry," said Carl Pilcher, director of the National Aeronautics and Space Administration's Astrobiology Institute, which co-funded the studies. He said the results support the theory that Earth and life on it evolved together.

The findings are reported in research papers in the journal Science.