LIFE ON THE EDGE: SURVIVING EARTH'S GREATEST EXTINCTIONS

For two hundred million years, the bacteria produced oxygen. It reacted with dissolved iron. Red rust sank to the seafloor. Then the bacteria died from their own waste. Dark sediments deposited on red layers. Red. Black. Red. Black. The electrocardiogram of a dying biosphere. Each wave left behind survivors. Stronger. More resistant. After two hundred million years, the bacteria were unstoppable. The cycle stopped. The pulse went silent.