Table_S1_Geochemical dataset.xlsx

Earth's first atmospheric oxygen rise between 2.43-2.1 billion years ago enabled complex life, but geochemical evidence shows earlier oceanic oxygen oases. New data from a 2.93-billion-year-old Canadian drill core reveal early surface water oxygen accumulation, predating atmospheric oxygen by 500 million years. Pulsed increases in oceanic phosphorus bioavailability, driven by anoxic recycling, likely boosted photosynthesis and organic carbon burial, influencing these early oxygen oases.