Well, they're not around here, you might say, and you are right, thankfully. Since these are not our usual lakes, we won't say anymore about them. We will discuss this category in much more detail since it includes most of the lakes we know. There are some of these lakes around so we'll discuss the meromictic lakes later. First we need to know something about the temperature and density relationship of water.
Water is really an amazing substance.
It is a rare substance where the solid state is lighter than the liquid state, but it is true for water. Ice floats, luckily for us. So, if we start with ice at 0C, we have a lattice type of structure that is lighter and less dense than water, and the ice floats. This really takes a lot of heat energy. The water is more dense than the ice and it continues to absorb heat and to get warmer.