Scientists discovered something strange in the deep sea | The Dark Oxygen Mystery

Scientists discovered something strange in the deep sea | The Dark Oxygen Mystery

Long before the first leaf unfurled toward the sun, before the skies turned blue with oxygen, Earth’s surface was a murky soup. Volcanoes spewed gases into the air, and oceans simmered with chemical reactions. There was no oxygen, no ozone layer, no life as we know it. Yet, somewhere in the shadows—deep in cracks in rocks, in the abyssal plains of the sea, and beneath thick layers of sediment—life quietly began to emerge.

This life wasn’t breathing the oxygen we take for granted today. It didn’t photosynthesize. It didn’t bask in sunlight. It existed in the dark. And now, billions of years later, that ancient world still exists. It hasn’t gone away. It’s under our feet, under our oceans, inside caves and crusts of basalt. And in that world, a new mystery has begun to stir: oxygen—in the dark.

How can oxygen, a gas so strongly associated with photosynthesis and sunlight, be present and persist in places utterly devoid of light?

This is the mystery of dark oxygen.