Thanks, Andrew.  Since the reefs that corals build support entire communities of animals and plants, their ever more rapid disappearance may represent the first big destruction of an ecosystem caused (to a great extent at least) by global warming.

Other ecosystems too are endangered on account of global warming, apparently, such as where polar ice is melting away from sea coasts, where permafrost is melting, where alpine environments are moving uphill, where the more dense concentrations of moisture are shifting vertically in rainforest canopies.  But the corals deserve special consideration, inasmuch as they seem to be pressured by more than one CO2-related challenge at once.

I assume the rise in water temperature either directly affects adversely the corals' metabolism (but how?), or gives a positive advantage to parasitic or disease-bearing organisms that infect them.

As for ocean acidification, it is my understanding that there has been a slight shift in pH levels away from the alkaline end and toward the acid end; but technically the waters of the ocean are not yet acidified.  Still, it is apparently enough to impede the growth in corals of the harder parts of their bodies.  And presumably it is affecting other marine invertebrates, including crustaceans and mollusks, who have exoskeletons in which calcium is an important component.

After all, it is well known in fossil preparation that when a relatively small and delicate vertebrate fossil is found in a limestone matrix, often the best thing to do is let the whole piece soak in a weak acid bath.  And limestone, of course, is petrified ancient sea floors, onto which the shells of countless minuscule crustaceans had precipitated.

Mind you, I am not a scientist, and cannot vouch for anything I have written, which is just thrown together from here and there.  Anyone who can correct me, please do so.