Dead Coral

Coral polyps divide and as the daughter polyps grow and eventually divide themselves the coral colony expands. Lophelia  polyps are thought to live for between 10 and 15 years after which they die back leaving bare skeletons. This dead coral framework can trap sands and mud (helping to build the reef structure) and is an important habitat for many other species.

Over time the dead coral is broken apart, especially by other animals that bore into the structure, and the coral rubble falls to the seafloor. Here the rubble can accumulate to form aprons around the base of the reef. Coral rubble often contains the most animal varieties on the reef, with hundreds, if not thousands of species of many shapes and sizes. The larger, more conspicuous include other species of cold-water coral, actinians and sponges. Smaller organisms such as bivalves, hydrozoans, barnacles, gastropods, crustaceans and countless worms are frequently found crawling amongst the rubble and feeding from the fine sediment.

Slate Pencil Urchin Crab Spider Crab
Slate pencil urchin (Cidaris cidaris) crawls through broken coral, Galway Carbonate Mound © Ifremer & AWI (2003). A crab moves amongst dead coral rubble, Galway Carbonate Mound, 824m © J.M. Roberts, SAMS (2003). A spider crab wearing a covering of gorgonian coral © Ifremer & AWI (2002).
A slate pencil urchin (Cidaris cidaris) crawls over a reef growing on a carbonate mound. A crab walks across dead coral rubble. A spider crab wearing a covering of gorgonian coral