I wonder if the anti-GMO gang will get incensed w/ genetic manipulation to grow super coral?  Hmm.  Anyway, it wasn't specifically iterated, but it seems like there is still some research that needs to be done in order to make a pronouncement that is fact.  My theory, totally anecdotal, the recent (if you can call 20+ years recent) introduction of the box jellyfish bears some looking into.  The jellyfish seem to lay there polyps ~ 9 days after full moon nights.  With the increase in jellyfish numbers, turtles swarm to eat the jellies.  Additionally, attracting the sharks who eat the turtles.  When the polyps get laid on the reef, the critters that eat that stuff start swarming - on the reef.  The reef gets triple the critters it gets than normal and the waste from these critters goes thru da roof.  The reef starts sending out the pheromones to tell other nearby reefs that "we're gonna reproduce!" which tells whatever is bleaching the coral that a smorgasbord is about to happen..ta da!