What are these black masses floating on my pool?
I was looking in the wrong kingdom. After much searching I asked myself: are those eggs? Silly me, of course they are. I should have thought it from the start. Mosquitoes plant their eggs on water over night. I was confused because in the past I've never seen the eggs, only the larvae and the pupae in the water. So, that's what I have every morning floating in my pool, groups of mosquito eggs.
http://animalia-life.club/other/mosquito-eggs.html