“Understanding how Earth regulates climate both in the modern era but also in the distant past is critical for our understanding of planetary habitability,” said Noah Planavsky, a biogeochemist at Yale University. “This will help guide our search for life beyond our solar system and is an example of how the evolution of complex life fundamentally changed our planet.”
Research by a UC Riverside-led astrobiology team suggests oxygen conditions in the early surface ocean were low and unstable for most of the history of Earth and possibly delayed the emergence of animals for hundreds of millions of years.
The fact that microbial life flourished amid such low oxygen levels presents a problem for scientists hunting for extraterrestrial life, reports Lucas Joel in Scientific American. The presence of the gas in the atmosphere of a planet is considered a telltale sign that it could harbor life, explains Planavsky, a co-author of a study, published in the Proceedings of the National Academy of Sciences USA.
To read more, click here.