“In the next few decades, a lot of coral will die — that’s pretty much a given. And to be clear, this reality is absolutely devastating. Regardless of whether snorkeling is your thing, reefs are essential to human well-being: Coral reefs dampen waves that hit the shore, support commercial fisheries, and drive coastal tourism around the world. They’re also home to an incredible diversity of life that inspires wonder.”
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“But even as many corals die, reefs won’t exactly disappear. The 3D formation of a typical reef is made of hard corals that produce a skeleton-like structure. When the polyps die, they leave their skeletons behind. Animals that eat live coral, such as butterfly fish and certain marine snails, will likely vanish; plenty of other fish and crabs will stick around because they can hide among those skeletons. Algae will dominate on ailing reefs, as will “weedy” kinds of coral, like sea fans, that don’t typically build the reef’s structure.
Simply put, dead reefs aren’t so much lifeless as they are home to a new community of less sensitive (and often more common) species.”
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“On the timescale of decades, even much of the reef rubble will fade away, as there will be no (or few) live corals to build new skeletons and plenty of forces to erode the ones that remain. Remarkably, about 30 percent of the carbon dioxide that we pump into the atmosphere is absorbed by the oceans. When all that CO2 reacts with water, it makes the ocean more acidic, hastening the erosion of coral skeletons and other biological structures made of calcium carbonate.”
https://www.vox.com/climate/24137250/coral-reefs-bleaching-climate-change