Have you noticed lately while swimming that the surface water in the lake is very warm and deeper water is cooler? At this time in the summer, the lakes are separated into vertical layers like a cake; limnologists call this phenomenon stratification. Stratification is a major reason our Minnesota lakes behave the way they do. To understand lake stratification, we first must address the relationship between water density and temperature. Water is unique in that it is denser as a liquid than a solid; therefore, ice floats. If ice sank, our lakes would behave much differently in the winter! [Read more…]