Most chemistry and biology teachers will agree that students have a "disconnect" between these two disciplines. This likely results from the categorization of the topics into two classes or two separate years of study. In this article, the author provides one example of how the two disciplines can be related in an environmental application that many students have first-hand experience with: diving into a stratified water body. The stratification (a physical process) is explained first, and then the chemistry that results from the stratification is considered. He presents an integrated limnology, microbiology and chemistry exercise for teaching summer lake stratification, nutrient consumption and chemical thermodynamics, and discusses his observations and suggestions for using this exercise. (Contains 6 figures.)