thenewgreen: My uncle lives on a large lake in Brighton MI. A couple of years ago their dog died shortly after swimming in the lake. He thinks it was from the algae. I'm not sure what makes him think this other than that the dog was in good health. No autopsy was performed to the best of my knowledge, though I wouldn't be surprised if it was... he loved that dog.
Despite how harmful they are, the algae blooms are very pretty from the aerial photography.