BEIJING, Sept. 28 (Xinhuanet) -- Two studies reveal that small amounts of oxygen were in the oceans and possibly in the atmosphere around 2.5 billion years ago, 50 to 100 million years earlier than when it was previously thought.

Researchers say the findings indicate the possibility that oxygen-producing microbes, such as cyanobacteria, were producing oxygen 100 million years before the Great Oxidation Event between 2.3 billion and 2.4 billion years ago.

So, why did it take up to 100 million years between the initial puffs of atmospheric oxygen and the Oxidation Event?

The authors suggest a complex and interdependent dance between biological and geological processes can explain the gap. "It becomes a co-evolutionary dance or interplay," said Ariel Anbar, a biogeochemist at Arizona State University and lead author of one of the studies.

An outside scientist not involved in either study, Carl Pilcher, director of the NASA Astrobiology Institute, expanded on the idea of an intricate link between life and the planet.

"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," Pilcher said. The new results "support the idea that our planet and the life on it evolved together."

Both studies are detailed in the Sept. 28 issue of the journal Science.

(Agencies)