Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.
Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles. Sea anemones are mostly solitary, but the majority of corals are colonial, being formed by the budding of new polyps from an original, founding individual. Colonies are strengthened by calcium carbonate and other materials and take various massive, plate-like, bushy or leafy forms.
Alcyonacea are a species of sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Whilst not in a strict taxonomic sense, Alcyonacea are commonly known as "soft corals" (Octocorallia) that are quite different from "true" corals (Scleractinia). The term “soft coral” generally applies to organisms in the two orders Pennatulacea and Alcyonaceae with their polyps embedded within a fleshy mass of coenenchymal tissue. Consequently, the term “gorgonian coral” is commonly handled to multiple species in the Alcyonaceae order that produce a mineralized skeletal axis composed of calcite and the proteinaceous material gorgonin only and corresponds to only one of several families within the formally accepted taxon Gorgoniidae (Scleractinia). These can be found in order Malacalcyonacea (taxonomic synonyms of include : Alcyoniina, Holaxonia, Protoalcyonaria, Scleraxonia, and Stolonifera. They are sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Common names for subsets of this order are sea fans and sea whips; others are similar to the sea pens of related order Pennatulacea. Individual tiny polyps form colonies that are normally erect, flattened, branching, and reminiscent of a fan. Others may be whiplike, bushy, or even encrusting. A colony can be several feet high and across, but only a few inches thick. They may be brightly coloured, often purple, red, or yellow. Photosynthetic gorgonians can be successfully kept in captive aquaria.
Aiptasia is a genus of a symbiotic cnidarian belonging to the class Anthozoa. Aiptasia is a widely distributed genus of temperate and tropical sea anemones of benthic lifestyle typically found living on mangrove roots and hard substrates. These anemones, as well as many other cnidarian species, often contain symbiotic dinoflagellate unicellular algae of the genus Symbiodinium living inside nutritive cells. The symbionts provide food mainly in the form of lipids and sugars produced from photosynthesis to the host while the hosts provides inorganic nutrients and a constant and protective environment to the algae. Species of Aiptasia are relatively weedy anemones able to withstand a relatively wide range of salinities and other water quality conditions. In the case of A. pallida and A. pulchella, their hardiness coupled with their ability to reproduce very quickly and out-compete other species in culture gives these anemones the status of pest from the perspective of coral reef aquarium hobbyists. These very characteristics make them easy to grow in the laboratory and thus they are extensively used as model organisms for scientific study. In this respect, Aiptasia have contributed a significant amount of knowledge regarding cnidarian biology, especially human understanding of cnidarian-algal symbioses, a biological phenomenon crucial to the survival of corals and coral reef ecosystems. The dependence of coral reefs on the health of the symbiosis is dramatically illustrated by the devastating effects experienced by corals due to the loss of algal symbionts in response to environmental stress, a phenomenon known as coral bleaching.
Porites astreoides, commonly known as mustard hill coral or yellow porites, is a colonial species of stony coral in the family Poritidae.
Holaxonia is a suborder of soft corals, a member of the phylum Cnidaria. Members of this suborder are sometimes known as gorgonians and include the sea blades, the sea fans, the sea rods and the sea whips. These soft corals are colonial, sessile organisms and are generally tree-like in structure. They do not have a hard skeleton composed of calcium carbonate but have a firm but pliable, central axial skeleton composed of a fibrous protein called gorgonin embedded in a tissue matrix, the coenenchyme. In some genera this is permeated with a calcareous substance in the form of fused spicules. Members of this suborder are characterized by having an unspiculated axis and often a soft, chambered central core. The polyps have eight-fold symmetry and in many species, especially in the families Gorgoniidae and Plexauridae, contain symbiotic photosynthetic algae called zooxanthellae. These soft corals are popular in salt water aquaria.
Gorgoniidae is a family of soft corals, a member of the subclass Octocorallia in the phylum Cnidaria. Nearly all the genera and species are native to the east and west coasts of America.
Gorgonia flabellum, also known as the Venus fan, Venus sea fan, West Indian sea fan, and purple gorgonian seafan, is a species of sea fan, a sessile colonial soft coral.
Pseudodiploria clivosa, the knobby brain coral, is a colonial species of stony coral in the family Mussidae. It occurs in shallow water in the West Atlantic Ocean and Caribbean Sea.
Plexaurella nutans, the giant slit-pore sea rod, is a tall species of soft coral in the family Plexauridae. It is a relatively uncommon species and is found in shallow seas in the Caribbean region.
Pocillopora verrucosa, commonly known as cauliflower coral, rasp coral, or knob-horned coral, is a species of stony coral in the family Pocilloporidae. It is native to tropical and subtropical parts of the Indian and Pacific Oceans.
Paramuricea clavata, the violescent sea-whip, is a species of colonial soft coral in the family Plexauridae. It is found in shallow seas of the north-eastern Atlantic Ocean and the north-western Mediterranean Sea as well as Ionian Sea. This species was first described by the French naturalist Antoine Risso in 1826.
Eunicella cavolini, commonly known as the yellow gorgonian or yellow sea whip, is a species of colonial soft coral in the family Gorgoniidae. It is native to parts of the eastern Atlantic Ocean, Mediterranean Sea and Ionian Sea where it is a common species.
Alcyonium coralloides, commonly known as false coral, is a colonial species of soft coral in the family Alcyoniidae. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea. In the former location it generally grows as sheets or small lobes but in the latter it is parasitic and overgrows sea fans.
Eunicella singularis, the white gorgonian, is a species of colonial soft coral, a sea fan in the family Gorgoniidae. It is found in the western Mediterranean Sea, Adriatic Sea and Ionian Sea. It was first described in 1791 by the German naturalist Eugenius Johann Christoph Esper.
Pseudoplexaura porosa, commonly known as the porous sea rod or the porous false plexaura, is a species of gorgonian-type colonial octocoral in the family Plexauridae. It is native to the Caribbean Sea and the Gulf of Mexico.
Anthelia glauca, the giant anthelia, is a species of soft coral in the family Xeniidae. It is a colonial species and is found in shallow water in the Indo-Pacific region.
Chrysogorgia elegans is a species of soft coral in the family Chrysogorgiidae. It is found in the Gulf of Mexico, the Mediterranean Sea and the North Atlantic Ocean. Soft coral can also be referred to as sea fans, sea whips, sea feathers, and sea pens.
Antillogorgia elisabethae is a species of soft coral found in the Caribbean Sea in the shape of a sea plume. It resides from depths of 25 metres (82 ft) to 30 metres (98 ft), often at reef drop-offs. It looks like a plume of feathery appendages with radial symmetry. The branches of A. elisabethae are pinnate and distichous, and will orient themselves in the direction of the ocean current. It ranges in size from 0.3 metres (0.98 ft) to 2 metres (6.6 ft). It is considered commercially important as it is harvested for analgesics and cosmetic creams. The compound that is believed to cause its beneficial effects is Pseudopterosin A, a diterpene glycoside, a selective analgesic. A. elisabethae is also used in fish tanks as a part of the commercial pet industry. The species has a Least Concern conservation status.
Balanophyllia elegans, the orange coral or orange cup coral, is a species of solitary cup coral, a stony coral in the family Dendrophylliidae. It is native to the eastern Pacific Ocean. As an azooxanthellate species, it does not contain symbiotic dinoflagellates in its tissues in the way that most corals do.
