Oceans may well be shrinking — Science News, March ten, 1973
The oceans of the planet may well be steadily shrinking, leaking gradually away into the Earth’s mantle…. Though the oceans are continuously getting gradually augmented by water carried up from Earth’s interior by volcanic activity … some course of action such as sea-floor spreading appears to be letting the water seep away additional quickly than it is replaced.
Scientists traced the ocean’s leak to subduction zones, places exactly where tectonic plates collide and the heavier of the two sinks into the mantle. It is nevertheless unclear how significantly water has cycled amongst the deep ocean and mantle by means of the ages. A 2019 evaluation suggests that sea levels have dropped by an typical of up to 130 meters more than the final 230 million years, in element due to Pangea’s breakup generating new subduction zones. Meanwhile, molten rock that bubbles up from the mantle as continents drift apart may well “rain” water back into the ocean, scientists reported in 2022. But considering the fact that Earth’s mantle can hold additional water as it cools (SN: six/13/14), the oceans’ mass may possibly shrink by 20 % just about every billion years.