If I had a 10km vertical tube of water, would the water at the bottom be quite hot?
The reasoning I have is that, as $p=\rho gh$ then as the depth increases, then so should the pressure. However, pressure in a fluid is caused by nothing other than the collision of water molecules against other things. If the pressure is very high, I would imagine the force of impact is very high, meaning that the water molecules have a high velocity and thus a high temperature.
Is this true? I have a feeling it's not but the argument I present seems ok.