Scientists have long puzzled over why the Earth’s ozone layer, crucial for protecting life from cosmic rays, didn’t form immediately after oxygen levels rose. A new study published in Proceedings of the National Academy of Sciences sheds light on this mystery. Researchers from Yale University found evidence that ancient iodine compounds may be responsible for delaying the formation of the ozone layer.
The ozone layer is a region in the upper atmosphere where ultraviolet radiation is absorbed, protecting life on Earth. It’s composed of three oxygen molecules and formed only a few hundred million years ago. Scientists had hypothesized that iodine could have played a role in this delay, as its compounds can deplete ozone.
Researchers analyzed ancient rock layers from the ocean floor to determine the chemical composition of the environment 2-500 million years ago. They discovered abundant iodine salts, which were released into the atmosphere and destroyed the ozone layer. As these substances decreased over time, the protective shell of our planet began to form. The study’s findings suggest that ancient iodine was a key factor in delaying the formation of the ozone layer, ultimately allowing life on Earth to thrive.
Source: https://universemagazine.com/en/iodine-nearly-left-the-earth-without-ozone-layer