Fig. 1From: Deep mantle melting, global water circulation and its implications for the stability of the ocean massA cartoon showing the nature of global water circulation. Water is added to the oceans by degassing associated with volcanism. Some surface water goes back to Earth’s interior by subduction. A large fraction of subducted water comes back to the surface by arc volcanism. However, water stored in relatively deep portions of a subducting plate survives and is transported to the deep mantle contributing to regassing the mantle transition zone and deeper partBack to article page