Not all corals are found on island coasts or in shallow seas. In fact, over half of all known coral species are found in deep, dark waters where temperatures range from 4-12°C (39-54°F). For this reason, we call these corals the “cold-water” or “deep-sea” corals. They are found all over the world. Some locations are home to just a few corals while others feature dense coral mounds.
Stony corals, also known as hard corals, refer to coral species that produce a hard skeleton made of calcium carbonate. These corals are especially important because this skeleton provides important habitat to other animals even long after that coral has died. Several NOAA Office of Ocean Exploration and Research expeditions have explored Lophelia pertusa colonies in the deep.