22 Jan 2021

Venus Sea Fan - An Unusual Looking Coral

 Gorgonia flabellum


 
Our oceans are full with wonders. Venus sea fan is one of them. It is also known as West Indian sea fan. A sea fan is a type of soft coral that looks like a Chinese hand fan. Like other soft corals a Venus sea fan does not have a hard calcium carbonate exo-skeleton.

These corals grow from a small base. After that branches and sub-branches of the main base make a complex colony.The branches grow parallel to the main plane. These soft corals can be yellow or purple in color. The purple ones look cooler, are not they?
 
Venus Sea Fan


Venus sea fans are usually smaller than the common sea fans. While the common sea fans can grow up to 2 meters, the former usually never grows more than 1 meter. The common ones also have a smoother age.

Venus sea fans usually grow in shallow water. They are rare below the depth of 10 meters. They only grow and thrive in clear sea waters. These corals can be found in the coral reefs of Bahamas and Florida. Strong water current is their favorite.
 
Gorgonia flabellum
 

These corals have calcite in their skeletons. Calcite is actually a more stable polymorph of calcium carbonate.There is also some kind of collagen like material. The corals are anchored into a hard substance in the sea floor.
 
A venus eafan coral
 
Venus sea fan has symbiotic relationship with a dinoflagellate alga, Symbiodium. The alga has chlorophyll and so can utilize sunlight. It produces food via photosynthesis for itself and also for its host. The coral also eats small microscopic plankton and other dissolved bio ingredients from sea water. There are also some polyps which are active feeders using tentacles to catch nearby prey.
 
Symbiodinium

 
 
Venus sea fans reproduce asexually. Just like some plants a new sea fan emerges from a broken branch. The colony detaches some branches of it which flows in the ocean current to being attached with some other rock somewhere on the ocean floor. There a new colony is formed.
 
 
Naturally, Venus sea fan is a strong species of coral. However, it is being threatened by the human activities like uncontrolled coastal developments, rising sea temperature due to global warming, and pollution. A lot of these soft corals are dying due to that.