Caribbean Corals-Fan Coral


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This is abundant down here and an old time favorite.  I remember over 10 years ago when I saw an Abyss guide find the uprooted Fan Corals and replant them in an effort to make sure that they could continue to propagate.  Ever since it is an automatic reaction for me to do the same thing.

Fan coral is a type of coral which develops a highly branched flexible skeleton which closely resembles a fan.  It is sometimes referred to as sea coral and a gorgonian, gorgonian being close to its latin name.

Most corals are single organisms.  The fan coral is not.  It is a colony of organisms known as polyps which band together and develop a supportive skeleton. In the case of sea fans, the polyps use bromine, iodine, and tyrosine to create a flexible substance known as gorgonin. The surface of a fan coral tends to be rough and it is resilient in addition to flexible, ensuring that sea fans can withstand heavy currents.  Its displacement comes from hevy currents and waves on shallower reefs that are a result of tropical storms and hurricanes.
The color of a fan coral varies, depending on the species and whether or not symbiotic algae are living inside the sea fan. Colors typically range from yellow to red, with the polyps located along the branching arms of the fan. The polyps have eight tentacles which they use to filter free-floating organisms from the water to eat. They may also feed on the symbiotic algae, if it is present. Because fan coral cannot actively hunt its prey, it requires strong currents to provide enough nutrition.

Fan coral is primarily nocturnal, with the polyps pulling their tentacles in during the day to protect themselves from predators and the potential for sun burn. These corals reproduce by mass-spawning eggs and sperm, which fuse in the water to become gametes. The gametes free-float until they find an area of sand or mud to settle in.  I say we have a fan coral night dive and see if we can actually witness this spawning of the fan coral.

There are over 500 species of fan coral, most of which are found in the Atlantic. These corals can live to be hundreds of years old, and they are very slow growing. Fan coral is also extremely vulnerable to human interference, as careless divers can break off arms, destroying decades of growth, and trawlers routinely rip out fan coral as they dredge the bottom of the ocean for fish. Fan corals are also vulnerable to deliberate harvest for commercial profit, and to nutrient runoff, which can trigger algae blooms which cloud the water, making it difficult for fan coral to live. Fan corals are mainly filter feeders; this especially being true for deep water varieties that are devoid of zooxanthellae. They can be found in waters as deep as 6000 feet, and they can grow to the size of a small tree. Deep water gorgonians are suspension feeders that feed on the marine snow dragged across their fronds by deep water currents. Some deep water corals have actually been dated to precede recorded history.

This is more information than i had known about the fan coral.  now i think we should go on a fan coral exploration hunt in the day and at night and actually check these suckers out!

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