Describe the overturn of a temperate lake, the life zones of a lake, and the organisms you would expect to find in each life zone.

a. The overturn of a temperate lake occurs when surface water cools and becomes denser, sinking to the bottom and causing deeper waters to rise, mixing the lake's layers.
b. Life zones in a lake include littoral, limnetic, and profundal zones.
c. Littoral zone: Supports rooted aquatic plants, insects, crustaceans, and small fish.
d. Limnetic zone: Inhabited by plankton, small fish, and larger predatory fish.
e. Profundal zone: Houses decomposers, bottom-dwelling organisms, and deep-water fish.