White is an unusual color for coral. It looks quite attractive, and it's well worthy of a picture. Unfortunately, as its unnatural, it's also bad news. White coral isn't supposed to happen, and it's not a shade that appears when coral is healthy. It's caused when there's too much carbon dioxide in the water. That carbon dioxide is there either because it's been emitted into the sea, or because there aren't enough trees in the area to process the carbon dioxide and keep the levels down.
The coral can just about cope with being white, but it's a warning signal. If the carbon dioxide balance isn't corrected, the coral will die. That would have an unimaginable impact on the underwater ecosystem; coral plays a vital role in regulating life below the waves, often providing both home and shelter to smaller creatures.