Why does the temperature increase slightly when you go deeper into the water?

Question

Usually in a river or lake that is lets say about 6 meters deep, the temperature decreases when you go to greater depths. But how do you explain slight increases in temperature as you do deeper in water?

Or does it depend on whether its salty or fresh water?

Answer 1

it could be due to the magma from the mantle heating the water around a thin part of the crust, but that depends on how deep you are talking about.

Answer 2

Depends on the temperatures what is surrouding the water.

Answer 3

depends on currents.  Warm water is less dense than cold water and therefore will always migrate so that it is above the cold water.  The only way to encounter warmer water at depth is if it is warmed at depth or brought to depth by current.

I was an avid swimmer when younger and cannot think of a single example of water being warmer at depth unless I got myself into the wake of some kid that let loose with his bladder just before I got there, a rather disgusting event.

Answer 4

The deeper you go in some place, the hotter it gets since your reaching the earths core.