There are a couple of Lake Biology concepts that will be used though out our presentation and should be explained
	*Lake turnover is caused principally by seasonal temperature changes of a lake's surface water.
	*(Diagram) During the summer months, the lake stratifies, forming three distinct layers.  The upper most layer, also known as the epilimnion, consists of warm oxygenated water.  The bottom layer, also known as the hypolimnion, consists of colder water containing less oxygen because it trapped at the bottom where oxygen is being used by fish and decomposers.
	*Turnover occurs in the spring when the ice begins to melt again in the fall when water cools.  The surface water sinks to the bottom causing a mixing of the lake.  This results in oxygenation of the hypolimnion and brings nutrients, such as phosphorus to the surface.
	*Turnover is often followed by algae blooms because of the phosphorus increase in the upper layer allows phytoplankton populations to increase dramatically