Although some corals can catch small fish and plankton using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates in the genus Symbiodinium that live within their tissues.
These are commonly known as zooxanthellae and the corals that contain them are zooxanthellate corals.
Individual heads grow by asexual reproduction of polyps.
Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon.
As communities established themselves on the shelves, the reefs grew upwards, pacing rising sea levels.
Reefs that rose too slowly could become drowned reefs.
Unlike sea anemones, corals secrete hard carbonate exoskeletons which support and protect the coral polyps.
Most reefs grow best in warm, shallow, clear, sunny and agitated waters.
As the sea level rise continued, water topped most of the continental islands.Since the first European contact was made in 1513 by Spanish explorer Juan Ponce de León – who named it La Florida ( – Florida was a challenge for the European colonial powers before it gained statehood in the United States in 1845.It was a principal location of the Seminole Wars against the Native Americans, and racial segregation after the American Civil War.They are most commonly found at shallow depths in tropical waters, but deep water and cold water corals also exist on smaller scales in other areas.Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection.Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in length.A set of tentacles surround a central mouth opening. Over many generations, the colony thus creates a large skeleton that is characteristic of the species.Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups.The polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish.Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals.Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients.