Cold-water coral morphology and reef structure

Cold-water corals are members of a large group, the Cnidaria, related to animals like sea anemones and jellyfish. Cold-water corals vary from solitary corals, a single polyp enclosed in a skeleton, to framework-forming colonial corals that form reefs themselves home to thousands of other animals. So far, only six species of cold-water coral have been found that can build framework reefs, compared to over eight hundred tropical species!

At first glance cold-water corals show no movement, living fixed in place. Looking closer, the minute polyps (usually just a few millimetres in diameter) are constantly outstretched, ‘feeling’ for passing prey and potential food. If a predator comes near, the polyps retract their tentacles rapidly back into the protection of the coral’s skeleton.

This section focuses on the skeletons and reefs formed by scleractinian or stony corals.