There appears to be far more water locked deep within the Earth's crust than scientists have previously thought.
Some of the water is ancient and has been sitting there for between 1 and 2.5 billions of years old and is stored many kilometres below the surface.
There is thought to be more fresh water than all the World's rivers, swamps and lakes combined. The volume has been calculated at around 11 million cubic kilometres, which is 2.5 cubic miles in old units
A team of researchers found that the water was reacting with the rock to release hydrogen, which is a potential food source.
The question is - could the deep crust be harbouring as yet undiscovered life forms? The search is on to find it, and see just how much and where it is.