Tropical coral reefs are magical places, yet if all the world’s reefs were placed together they would occupy a relatively small area—less than half the size of France. These most diverse of marine ecosystems punch above their size, however, supporting up to a third of all marine species and acting as home to between hundreds of thousands or possibly millions of reef-associated organisms—even marine biologists just don’t know how many.
This tremendous diversity and spectacular array of different life forms has been an endless source of fascination. In 1802, while undertaking the first circumnavigation of Australia, Captain Matthew Flinders described a reef in the southern Great Barrier Reef as “equalling in beauty and grandeur the most favourite parterre of the curious florist.”
How things have changed. Looking underwater in the northern sector of the reef in 2016, he would have seen no vibrant colors but a ghostly white scene of dead and dying corals, rapidly being overgrown by seaweeds. This was part of a protracted mass coral bleaching event, the third global event since 1998, which has affected many of the world’s coral reefs since mid-2014 and is still ongoing as of late 2016. So what has gone wrong in the intervening two centuries for the Great Barrier Reef, and why are more than 60 percent of the world’s tropical coral reefs considered to be under immediate and direct threat from local causes? And why should humanity care what happens?