reporter: in the coastal village of plasencia, locals survive on fishing and tourism, both of which dependn the reef. monique: you know, i come out on this trip many times, many days, and i say, "man, i am so blessed." and i look at everything that is in front of me and i think, "i hope one day this doesn't become a memory." reporter: beneath the surface, it's clear why the reef is struggling. the corals have been dying off. e seawaterer is too warm, , to acididic. and the frequent cyclones have wreaked havoc. hehere, climate e change is tug evererything grey.y. together w with marine b biolot and the frequent cyclones have lisa carne and her organization fragments of hope, monique is re-building the corals. lisa: we're overdue, and so there's no time to waste right now. the corals are basically like the forest in the sea, so just like the trees in the forest provide habitat and shelter for so many other animals, the corals do the same on the reef. reporter: very meticulously, after much research and carell sectioion, ty takeke aew fragagments of some e especiay hardy, quiuick-growing c co