That helps my understanding a lot Bocomo. Thanks for the info! I always thought that the water near the bottom would be thermally warmed by the surrounding earth, kind of like how a cave is always 60 degrees F. I would, now surmise that the opposite is happening. The surrounding earth is being overpowered and cooled by the cooler, sinking water.
I'll have to put more thought into this to really wrap my head around it.
