Privileged Planet: when did large amounts of oxygen appear (Introduction)

by David Turell , Thursday, January 06, 2022, 19:16 (1053 days ago) @ David Turell

Mainly in the Great oxygenation event:

https://www.sciencedaily.com/releases/2022/01/220105151338.htm

"Evidence arguing for a "whiff of oxygen" before the Earth's Great Oxygenation Event 2.3 billion years ago are chemical signatures that were probably introduced at a much later time, according to research published in Science Advances.

"The result rewinds previous research findings that atmospheric oxygen existed prior to the so-called Great Oxygenation Event-known to researchers as "GOE"- and has the potential to rewrite what is known of the planet's past.

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"Additional analysis conducted as part of the study reconfirms that Earth's atmosphere featured exceedingly low oxygen levels prior to 2.3 billion years ago.

"'We used new tools to investigate the origins of the signals of trace oxygen," said Jena Johnson, an assistant professor of earth and environmental sciences at the University of Michigan and co-author of the study. "We found that a series of changes after the sediments were deposited on the seafloor were likely responsible for the chemical evidence of oxygen."

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"'Our new, high-resolution data clearly indicates that the sedimentary context of chemical signals has to be carefully considered in all ancient records," said Johnson.

"In addition to providing an alternate explanation for oxygen proxies that were found in the Mount McRae Shale, the team confirmed that the level of atmospheric oxygen at the time before the Great Oxygenation Event was very low, calling it "negligible" in the approximate period 150 million years before the abrupt change.

"The findings call into question the early existence of cyanobacteria, instead supporting other hypotheses that oxygen-generating photosynthesis evolved only shortly before the Great Oxygenation Event."

Comment: If life appeared 3.8 by ago, its chemical processes did not need oxygen. It is obvious more complex life forms were allowed to appear as more oxygen became available. And an obvious drive toward complexity existed, I propose designed by god.