Water inside the earth

At https://phys.org/news/2017-06-mid-mantle-earth-oceans.html … Japanese and German researchers have found evidence that suggests the middle of the Mantle may hold as much water as the oceans on the surface. That is a lot of water. The experiment and research was published at Science Advances (an open access site) and involves the minerals wadsleyite and ringwoodite, thought to exist in quantity in the middle Mantle zone, and experiments how these minerals can absorb water. The researchers say they have been able to calculate how water logged the minerals are – but more testing will be done. If scientists can prove, beyond a doubt, how much water is in the centre of the Mantle, it would call into question the consensus theory water was brought to earth via comets. See Science Advances 7th June 2017 volume 3 no 60 1603024 (DOI:10.1126/scieadv.1603024) and http://advances.sciencemag.org/content/3/6/e1603024.full