Ancient microbes may have used oxygen 500 million years before it filled Earth’s atmosphere
MIT researchers used molecular clocks to trace heme-copper oxygen reductase enzymes back roughly 500 million years before the Great Oxidation Event, implying early microbes adjacent to cyanobacteria consumed nascent oxygen and slowed its atmospheric accumulation.
Why it mattersEvidence that heme-copper oxygen reductase predates the GOE should prompt prioritizing funding for comparative oxidative-stress studies.