Have you ever wondered what is happening beneath the ice on a frozen lake? How do fish and other organisms survive for so long beneath the frozen surface? Let's back up just a bit to talk about what happens before the lake freezes. During the summer, most lakes are thermally stratified. Warm lower density water sits on top of colder higher density water. As summer transitions to fall, the upper layers cool, breaking down that density difference. Eventually, the surface of the lake cools to 4 degrees Celsius (39.2 degrees Fahrenheit), the temperature at which water is most dense. This causes…