A massive deep-sea coral die-off was discovered this week about 7 miles southwest of the source of the Gulf of Mexico oil spill. Large communities of several types of bottom-dwelling coral were found covered with a dark substance at depths of about 4,600 feet near the damaged Deepwater Horizon wellhead. Eric Cordes, a Temple marine scientist, said his colleagues have identified about 25 other sites in the vicinity of the well where similar damage may have occurred. When coral is threatened, its first reaction is to release large amounts of mucus, "and anything drifting by in the water column would get bound up in this mucus. And that is what this (brown) substance would be: A variety of things bound up in the mucus."