Читать книгу Diving Indonesia Periplus Adventure Guid онлайн

74 страница из 170

Xenia, particularly common in Indonesia, has perhaps the largest individual polyps of any soft coral, each 6-8 centimeters long. The white (also tan, or light blue) polyps grow in clusters, and the tentacles at the end of each are feathery. These continually open and close, like numerous grasping hands. In Xenia one can easily count eight tentacles, which is one feature that distinguishes soft corals (Octocorallia) from hard corals and anemones (Zoantharia) which have six, or multiples of six, tentacles.

Gorgonians. Gorgonians (order Gorgonaceae) have a strong, horny skeleton, which gives strength and support without sacrificing flexibility. They tend to grow on the deeper parts of the reef, away from strong wave action. They live by filter feeding, and to maximize the water flow across their surfaces always grow at right angles to the prevailing current. Where the tidal current flows along the reef, gorgonians grow with their long axis vertical. Sometimes, however, particularly on some of the big walls in Indonesia, large sea fans can be seen growing horizontally out from the reef wall, to take advantage of the current upwelling.