Earth got first whiff of oxygen 3.2 billion years ago
Rock record shows signs of oxidation 200 million years earlier than previously thought
![modern cyanobacteria](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/09/090415_ts_oxygenmainnew_free.jpg?fit=860%2C460&ssl=1)
OXYGEN’S ORIGINS The first whiff of oxygen in Earth’s oceans came 200 million years earlier than previously known, new research finds. The oxygen-expelling organisms responsible were probably the forebears of modern cyanobacteria, shown.
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