Found this article on another web site. It explains how water pressure changes with approaching cold fronts at various depths in a lake. Note the increase in water pressure is constant with the change in depth. There are two graphs that will help explain what happens to the water pressure at different depths. I think you will learn something from this article. It's not all encompasing but it does explain the concept of water pressure at different depths pretty well. Being an Environmental Scientist myself I can understand everything in this article. If you have not taken classes in Ecology, Chemisty or Physics you may or may not comprehend this material.

I think his graphs help to explain a concept of how a fish can adust it's depth easily to maintain a constant pressure on it's body.

http://www.wmi.org/bassfish/articles/T199.htm

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