Coral Reefs

Coral reefs support [blank] marine life than any other ocean ecosystem and are, not surprisingly, a favorite pursuit [blank] many divers. But as well as being physically and biologically spectacular, coral reefs also sustain the livelihoods of over half a billion people. What's more, this number [blank] expected to double in coming decades while the area of high-quality reef is expected to halve. In combination [blank] the very real threat of climate change, which could lead to increased seawater temperatures and ocean acidification, we start to arrive at some quite frightening scenarios.