Acropora

Acropora is a genus of coral within the Family Scleractinia (Stony corals). It takes on a very interesting shapes many of which resemble antlers. Like all corals they exist as a colony made up of a bunch of individual polyps. The polyps secrete a calcium carbonate housing that becomes the basis of coral reefs habitats.

Acropora have been decreasing in numbers due to disease outbreaks, and damage due to human activities.

Anatomy
Acropora corals come in a variety of shapes and sizes depending on where they come from. They are all sessile. In shallow waters acropora tends to be in round bushes while the large plated clusters will only be found in the deeper water. Acropora can be plated, bushy, or in clusters. It all depends on what species they are. Acropora often change shapes due to the movement of water and the amount of sunlight they get daily. For example the Staghorn Coral, also known as the Acropora Cervicornis, is a branching coral, that has long cylindrical branches that jet out from the center. Another unique species of Acropora is the Palmata or more commonly referred to as the Elkhorn, it has very thick-plated branches. It is one of the largest growing colonies of all Acropora. Acropora comes in such a huge range of shapes and sizes which is what makes them so unique.

Reproduction
Acropora reproduce both asexually and sexually. When Acropora reproduce asexually through fragmentation (when broken off, they reattach in another place). This coral exhibits the fastest growth out of all known western Atlantic corals.

Sexual reproduction occurs when gametes are released into the water. They usually do this once each year around August or September. Individual colonies are hermaphrodites (both male and female) and will release millions of gametes. The acropora larvae, referred to as planula, live in the plankton for several days until finding a suitable area to settle down in. In the end, very few larvae survive to settle and metamorphose (to change forms) into new colonies that are separated from the other colonies. because of this, there is a decrease in the variety that used to be see in Acropora. 

Ecology
Staghorn coral are found in waters from 0-98 feet deep throughout the Florida Keys, the Bahamas, and the Caribbean islands. This coral occurs in the western Gulf of Mexico, but is absent from U.S. waters in the Gulf of Mexico. It also occurs in Bermuda and the west coast of South America. The northern limit is on the east coast of Florida, near Boca Raton.

Staghorn coral, like many corals, receive most of their energy and oxygen from symbiotic organisms called zooxanthellae.

Threats
Since the 1980s, the population of Staghorn Corals have collapsed. The main cause is disease outbreaks. The main disease is white band disease.

This disease is characterized by tissue that peels or sloughs off the coral skeleton in a uniform band, generally beginning at the base of the colony and working its way up to branch tips. The band ranges from a few millimeters up to 10 cm wide, and tissue is lost at a rate of about 5 mm per day.

The other causes are hurricanes, bleaching, algae overgrowth, human impacts, and other factors. This species is also really susceptible to damage from water treatment. 

Related References

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