Bathymetry
An Oceanographer. Marine Biologist, that sort of thing.
It is the mid-ocean ridge.
That would be a marine biologist.
Aliens
It is the mid-ocean ridge.
A scientist.
The edges of the continental plates under water are called the continental shelf.
Scientist call the seahorse a "Hippocampus"; a latin word
A biotechnology scientist.
A military scientist
I have no idea. Call a scientist or something I have no idea. Call a scientist or something
In the UK we call it the ground floor.