not to mention the fact that Japanese scientists are convinced the Earth's mantle contains 5 times as much water as the surface...
Opening line of the link (my bolding) :
Molten rocks deep in the earths interior may be surprisingly wet, Japanese researchers say.
Towards the end of the article :
The Japanese experiments don't guarantee that that's the case, of course, because the researchers haven't actually measured the mantle. No one is ever likely to get a direct sample of material from the fiery mantle itself. But by simulating mantle-like conditions in the lab, Murakami and his colleagues have demonstrated that a water-rich inner Earth is plausible.
"may" "plausible" - not exactly "convinced" I would say.
Confused ? You will be...