Life on the reef
Live coral dominates this area. The coral polyps actively feed in the water column, catching passing plankton and other food particles. The corals are covered in a layer of mucus and are able to prevent most other animals overgrowing them. But we do know about a few specialists who are able to live in amongst the live corals.
The worm Eunice norvegica lives on the coral skeleton where it builds a delicate parchment tube. Over time the coral encases this tube in its limestone skeleton effectively incorporating it into the reef framework. By observing the worms living in Lophelia corals in aquarium tanks we have learnt more about their relationship. The worms explore the coral branches perhaps helping to keep them clear of debris and defending them from attack. Interestingly the worms are strong enough to move small coral colonies and join them together. It seems that over time this behaviour will help build patches of coral and quicken reef growth. Other animals living with live coral are not so helpful. The parasitic foraminiferan Hyrrokin sarcophaga etches into the skeleton feeding on live polyps.