• Oxygen became stable in atmosphere ~2.3 billion years ago during Great Oxidation Event. • MIT study shows aerobic respiration enzyme evolved hundreds of millions of years earlier. • Early microbes likely used oxygen long before it accumulated in air. • Cyanobacteria produced oxygen ~2.9 billion years ago, but it was consumed by rocks. • Chemical reactions with Earth’s crust removed early oxygen, delaying atmospheric buildup. • Findings help explain long mystery of delayed oxygen accumulation.
Article Summaries:
- MIT geobiologists have found evidence that a key oxygen‑processing enzyme evolved during the Mesoarchean, hundreds of millions of years before the Great Oxidation Event (GOE). The enzyme, which allows organisms to consume oxygen, suggests that early microbes living near cyanobacteria may have used the gas as it was produced, thereby slowing its accumulation in the atmosphere. This finding implies that life adapted to oxygen far earlier and more creatively than previously thought, potentially explaining why atmospheric oxygen did not rise until the GOE around 2.3 billion years ago.
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