Off the coast of St. Thomas in the U.S. Virgin Islands, a group of scientists is tearing a reef apart in a feverish attempt to save some of its coral.

They are battling a fast-moving, lethal disease that researchers say is unprecedented in the speed with which it can damage large numbers of coral species across the Caribbean Sea.

Breaking their cardinal rule to never touch the coral, the scientists are removing diseased specimens to try to stop the disease spreading and save what remains.