August 21, 2014, 5:58 pm

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  • Cold-water coral feeding
  • Cold-water coral feeding
1. Close up of a Lophelia pertusa polyp © R. Milligan (2005). 2. Lophelia tentacles try to catch food © S.W. Ross

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Feeding and Food Supply

Unlike many species of tropical corals, cold-water corals feed by snatching prey out of the water column. They have a series of tractable tentacles which drape loosely in the water as the polyps wait for the food to come to them. Cold-water corals are sessile, they don't move in the search for food. Therefore they are often found in areas with a high current speed and a plentiful food supply. Seafans and other cold-water species are often found orientated to the direction of current flow, increasing the amount of prey which gets washed past and into the waiting polyps.

Each polyp of Lophelia has 16 tentacles, they use them like nets, waving them in the moving water. When a food particle or animal touches a tentacle, specialised cells called nematocysts inject a stunning poison into the prey. The prey is rendered immobile, and the polyp gently moves the prey into its mouth. Lophelia is generalist in its food preference, it will eat almost anything. In the laboratory it has been observed taking live zooplankton such as chaetognaths, small crustaceans and larger species such as krill. It has also been shown that Lophelia will take dead food particles of several different fish species. If it didn't like it, it would spit it out and try the next one. Sometimes, unsuitable food or dirt can float into the tentacles, the coral can push it out and begin waiting for the next particle.

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