Coral reefs across the globe are on the verge of collapse, but unless you’re a scuba diver or a snorkeler, you probably haven’t seen it. Rising ocean temperatures cause coral bleaching, which can wipe out entire sections of reef. We’ve already lost 25 to 40 percent of the world’s coral, and in Florida there’s been a loss of up to 98% of two coral species.

As reefs die off all around the world, researchers are frantically trying to find ways to save them. One promising method is to breed corals that seem to be more resilient to rising ocean temperatures, and then return them to the sea to grow again. The hope is to create tougher reefs. In this piece, we visit the Florida Keys, the only reef in the Continental U.S. to take a deep look at two pioneering techniques that may allow the restoration of reefs.