"Steven P. McNicoll" wrote

If the water had been 32 degrees F instead of 40 it would have been 8
degrees colder, but it still would have been liquid.

It is arguing nits, but I'll play the game you started.

If the water of the lake was all indeed at 32 degrees, it would all be a
giant ice cube. If it were all at 32.1 degrees, it would all be liquid.
The wave action has nothing to do with it.

In reality, lakes do not freeze because of wave action, because it keeps the
deeper warmer water mixed with the water at the surface that is trying to
get frozen because of the colder air. When the water just below the surface
is cold enough that it can't keep the water at the surface warm enough, it
starts to freeze.

Water has the unusual property of getting less dense, when it gets to almost
freezing. That is the only thing that keeps lakes from freezing solid, from
the bottom up. Most things get more dense as they get colder, so the cold
sinks to the bottom of the container, but not water.
--
Jim in NC