Xenia (coral)

Xenia is a genus of octocorans from the coral reefs of the tropical Indo-Pacific and the Red Sea. FeaturesChange source text

These are animal colonies consisting of many individual polyps. Xenia species have a soft, secretive, very slimy, short stem, and non-retractable, monomorphous polyps. Some species also grow crusty. The single polyp has, as with all genera from the subclass Octocorallia, eight feathered tentacles. The sclerites of Xenia have the form of tiny leaflets. The color ranges from brown to beige to white. The polyps of many species carry characteristic pumping movements, which distribute the nutrients from the water better to all polyps and the oxygen is transported away from the coral tissue. The pulsating movements give the Xenia a selection advantage over other coral species. The photosynthesis of the symbiotic algae also produces oxygen radicals that damage the coral metabolism. In the course of ocean warming, the radicals cause some corals to shed and die the symbiotic algae. Through the movement of the Xenia, the radicals can be transported away better and thus do not disturb the symbiosis.

All Xenia species live in a symbiosis with unicellular, symbiotic algae (zooxanthellae), from which they refer to the majority of the required nutrients and oxygen. In addition, they also absorb organic substances from the surrounding water through the skin.

Xenia species can multiply vegetatively very quickly and form large monospecific stocks in shallow water near the water surface. Edit source text

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