It has been estimated that 75 percent of all coral reefs around the world are threatened, but there is also reason to hope. Though sensitive to variations in their environment, these animals are also remarkably adaptable in that they are willing to attach themselves to just about any hard surface they can find. This includes shipwrecks, undersea pipelines and even oil rigs. By repurposing wreckage on the sea floor, they also provide habitat for the countless other species that rely on the ecology of coral reefs for sustenance.