The old Florida guy in this video finds he can un-bleach his reef. Good for him! He's definitely onto something. What's going on?
My idea for coral bleaching is applicable more broadly to all ecosystems:
Deep ocean conditions tend to be highly stable. Species in it become highly evolved for that stability, dependent on it. Tidal estuary conditions are highly variable. Species evolved there are adapted for the instability. Stable conditions can become unstable for natural reasons such as 16th century multiple beached whales in Holland, infectious disease or red tide. With the corals, I'd take it that the GBR (Great Barrier Reef) is highly stable, much more stable than anywhere around Florida. My guess is that the Florida guy in the video has picked up a subspecies more tolerant of instability. Such would be much easier to find in Florida than on the GBR. Over the long haul, the GBR will repopulate because the sunlight and nutrients are still there. It could repopulate rather quickly. Sadly, that would shame a lot of doomsdayers (who are conscientious folk).
What's going to be really exciting is when corn, rice, and wheat monocultures get hit by something new.