Deep sea pressure

[Henryn]

How do deep sea creatures and plants withstand such large pressures?

[SuperBunny]

Deep sea dwelling creatures do not breathe air. As their bodies do not contain large volumes of air, but contain water instead, the pressure inside them will vary with the pressure of the water outside, and whereas a human's lungs will eventually collapse at depth, an seabed dwelling creature's body will be in equilibrium with its environment. That's why Siguorney Weaver has to breathe that green liquid in The Abyss (which, incidently was one of the very first 12 certificate movies in the UK!).

[incitatus]

Superbunny's answer is only relevant in a situation where the external, pressurised environment is a liquid. If the pressurised medium is a gas it wouldnt matter if your body contained gas or not. The point is it is not pressure that kills you but pressure difference. If you were born at 15 atmospheres pressure, youd be fine, unless you came up to 1 atmosphere pressure, in which case you might pop. If the pressure outside is the same as the pressure inside it doesnt really matter what the absolute value is. The thing with the gas and liquid is due to the fact that gases are compressible and liquids arent.