Rose coral: Manicina areolata

  Manicina areolata also known as rose coral is native to the Caribbean Islands, the Bahamas, and the Southern Gulf of Mexico. I was able to see this species of coral at Old Sweat Bank in the Florida keys. It is a small stony coral that normally grows to about 4 inches in size. Its polyps sit in stony cups with their mouths turned sideways instead of up and down like other corals. This creates a ridge along the outside of the coral. Each polyp will stick out their tentacles at night to feed. During the day they are tucked away for protection from predation and the environment in general. 

      These corals often live in shallow waters on sandy or muddy substrates. They are one of the few corals that do not attach themselves to the bottom. They can often be found in sub tidal seagrass beds that have moderately high wave action and/or tidal flux. The high wave action causes them to be moved along the patch reef with the waves. This can be good because it allows the coral to reach new places for food and nutrients around the reef. They can be found up to 65 meters down but are the most abundant around 1 to 10 meters deep. 

      M. areolata is a hermaphrodite that reproduces by brooding. The gametes are produced in the spring on a full moon. Then the larvae is internally fertilized and released on the next new moon two weeks later. The larvae then drift until they settle on the bottom. The larvae settle into polyps and begin to form colonies by cloning itself to form new genetically identical polyps. Coral polyps have a symbiotic relationship with a small dinoflagellates called zooxanthellae which usually give the coral their color. M. areolata typically has a yellowish tan color. 

      This species of coral is classified under least concern by the IUCN red list, however there are increasing localized threats to these coral. Dredging and habitat destruction are some anthropogenic threats, while burial by sedimentation and hurricanes are some natural dangers. This coral is also susceptible to black band disease. This happens when small pathogens slowly eat away at the corals tissues. This disease is curable however most of the time goes untreated and the coral will eventually die. 

http://www.iucnredlist.org/details/132963/0
http://oceanservice.noaa.gov/education/kits/corals/coral10_disease.html  
https://en.wikipedia.org/wiki/Manicina_areolata