The pressures are too great, and no engineering or materials conceivable today would allow us to build livable-sized spaces on the deep sea floor.

FORBES: Why Don't We Spend More On Exploring The Oceans, Rather Than On Space Exploration?

They are also trying to understand the role that deep seas trenches play in earthquakes - these cracks in the sea floor are formed at the boundary of two tectonic plates and some believe the push and pull taking place deep underwater could be the cause of major earthquakes, such as the 2011 quake that resulted in such devastation in Japan.

BBC: James Cameron back on surface after deepest ocean dive

On Earth, sea-floor spreading is fuelled by molten rock upwelling from deep inside the Earth.

BBC: Enceladus has 'spreading surface'

Oil from the mile-deep well may be collecting in underwater clouds, potentially endangering a cornucopia of life from the sea floor to the surface, preliminary sampling by university researchers suggests.

WSJ: Gauging Harm to Ecosystem Could Take Years