Coral reef communities are undergoing marked declines due to a variety of stressors including disease. The sea fan coral, Gorgonia ventalina , is a tractable study system to investigate mechanisms of immunity to a naturally occurring pathogen. Functional studies in Gorgonia ventalina immunity indicate that several key pathways and cellular components are involved in response to natural microbial invaders, although to date the functional and regulatory pathways remain largely un-described. De novo assembly of the G. RNA-Seq analysis revealed differentially expressed genes in sea fans exposed to the Aplanochytrium parasite. Differentially expressed genes involved in immunity include pattern recognition molecules, anti-microbial peptides, and genes involved in wound repair and reactive oxygen species formation.
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However, it is not found in the Gulf of Mexico. In geographic ranges, it is found in the southeastern part of the of the nearctic region and the northwestern part of the neotropical region.
Colin, Gorgonia ventalina is distributed in a clumped, non-random distribution on coral reefs. Usually the most common gorgonian in coral reef habitats, it is primarily found on band and patch reefs.
In addition, the G. Gorgonia ventalina is usually purple but can vary to its less common colors of yellow-orange, yellow, and brown. In some cases, the color of the sea fan is a result of the environment and the chemicals in the enviroment. The principle pigments of the sea fan are fixed in the spicules needle-like parts of solid calcium carbonate. Colors result from chemical pigments produced in the spicules.
Since the color of the fan varies, the shape of the spicules is the only positive identifier of G. The spicules are small and fusiform. The polyps of the G. It is these individual polyps that form the sea fan. Gorgonia ventalina can be up to cm tall and cm wide, with anastomose branches, which form uniplanar, reticulate, fan-shaped colonies.
The branches are round or slightly compressed in the plane of the fan branch. Colin, ; Kester, ; Sterrer, Once a planulae polyp is settled on a hard surface, the young polyp creates a horizonatal layer of aragonite called the basal disk.
As the polyp grows upward, the base's margin also turns upward, forming a cup called the epitheca, which contains daily growth bands. These and other sturctures called septa form the skeletal boundaries found at the bottom of the coral polyps, which are left behind as a result of the upward growth of the polyp. Cary, May 15, ; Druffel, August 5, Gorgonian corals reproduce asexually by cloning or fragmentation, with external fertilization. The larvae typically spend several days as plankton before settling on a hard surface to begin formation of a colony.
Druffel, August 5, ; Gotelli, April There are several potential causes of death for G. The greatest cause of mortality is the disattachment of a colony from the substrate, most likely by wave action and storms. The overgrowth of the sea fan by other organisms is also another leading cause of death, especially by the hydrocoralline Millipora alcicornis and some encrusting bryozoa.
The cause of death is attributed to the lack of food and oxygen to the polyp. Recently, mortality has also been attributed to tumor growth. The tumors observed on G. The large tumor masses, which were most often concentrated at the axial bases of the affected clonies were clearly associated with tissue death necrosis and erosion of the affected coral.
According to Cary, there is no evidence that gorgonian colonies ever die from old age. Cary, May 15, ; Morse, et al. Gorgonia ventalina will orient according so that the "fan" is perpendicular to the motion of the waves.
This orientation only occurs in the adult sea fans. The young will grow in any direction, but as they mature will slowly shift until they are facing the current. Grigg, March In Anthozoans, specialized sensory organs are absent and nerves are arranged in nerve nets.
Most nerve cells allow impulses to travel in either direction. Hairlike projections on individual cells are mechanoreceptors and possible chemoreceptors. Some Anthozoans show a sensitivity to light. Brusca and Brusca, Gorgonia ventalina is carnivourous, feeding on zooplankton, especially at night.
A passive feeder, Gorgonia ventalina orients itself in the path of the sea current, so that the current flows past the fan and the zooplankton in the current are caught and eaten. In addition to being a carnivorous passive feeder, G. These zooxanthellae, usually Symbiodinium sp. Morse, et al.
Gorgonia ventalina contains secondary metabolites and calcified sclerites that act as anti-predator defenses. These anti-predator defenses act as successful feeding deterrents to the Cyphoma gibbosum , a common predator of the G. Cyphoma gibbosum feeds on gorgonian polyps by crawling slowly over the skeleton.
Trotonia hamnerorum is a specialized predator on G. Cronin, et al. Gorgonia ventalina has several ecosystem roles, primarily by serving as a substrate for many other organisms. For example, bivavle molluscs, sponges, and algae may grow on dead sections of the sea fan.
However, it is not known if the growth of these organisms kills the sections or if they invade after the coral is already dead. Certain organisms, such as the brittle star and the basket starfish, use the tall G.
There have been studies into the role that sea fans, including G. Conclusions were the limestone inner structure provides some of the base where other corals may attach to form more colonies. Cary, May 15, ; Colin, Compounds have been separated from G.
These compounds include octacoral. Gorgonia ventalina is popularly collected for use in aqauriums and as souvenirs. As a colorful addition to coral reef habitats, its presence also is important to ecotourism. It is the second largest ocean in the world after the Pacific Ocean. More specifically refers to a group of organisms in which members act as specialized subunits a continuous, modular society - as in clonal organisms.
Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals. Examples are cnidarians Phylum Cnidaria, jellyfish, anemones, and corals. Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.
Compare to phytoplankton. Bennett, I. The Great Barrier Reef. New York: Scribner. Brusca, R. Sunderland, Massachusetts: Sinauer Associates, Inc.. Cary, L. May 15, The Alcyonaria as a factor in reef limestone formation.
Colin, P. Caribbean Reef Invertebrates and Plants. Cronin, G. Hay, W. Finical, N. March Marine Ecology - Progress Series , : Druffel, E. August 5, Geochemistry of corals: proxies of past ocean chemistry, ocean circulation, and climate. Sci USA , Vol. Gotelli, N. April Ecology , 72 2 : Grigg, R. Orientation and growth form of sea fans. Limnology and Oceanography , 17 2 : - Guthrie, M. General Zoology.
Gorgonia ventalina , the purple sea fan , is a species of sea fan, an octocoral in the family Gorgoniidae. It is found in the western Atlantic Ocean and the Caribbean Sea. The skeleton is composed of calcite and gorgonion, a collagen -like compound. The calyces in which the polyps are embedded are in two rows along the branches. Many of the smaller branches are compressed in the plane of the fan, which distinguishes this species from the Venus sea fan Gorgonia flabellum.
Common sea fan Gorgonia ventalina Linnaeus, Description: Colonies are large, in a single plane, and fan shaped. The outline of the colony is an interconnected network of thin branches which enclose irregular, triangular or rectangular spaces. The branches are round or slightly compressed in the plane of the fan. The apertures are very small pores located in two rows along the edges of the branches. The fans can be large, 1. Color: The fans are purple, yellow or brownish in color. Habitat: Restricted to the outer reefs and patch reefs to 30 m.
Common Sea Fan
However, it is not found in the Gulf of Mexico. In geographic ranges, it is found in the southeastern part of the of the nearctic region and the northwestern part of the neotropical region. Colin, Gorgonia ventalina is distributed in a clumped, non-random distribution on coral reefs. Usually the most common gorgonian in coral reef habitats, it is primarily found on band and patch reefs. In addition, the G. Gorgonia ventalina is usually purple but can vary to its less common colors of yellow-orange, yellow, and brown.
Group: Corals Sponges Soft Corals and other groups. List by: Taxa Shape. Anthothelidae Erythropodium caribaeorum Antipatharia Antipathes caribbeana Antipathes pennacea Briareidae Briareum asbestinum Briareum species 1 Corallimorphs Ricordea florida General Views Mixed Communities Gorgoniidae Gorgonia flabellum Gorgonia mariae Gorgonia ventalina Iciligorgia schrammi Pseudopterogorgia acerosa Pseudopterogorgia americana Pseudopterogorgia bipinnata Pseudopterogorgia elisabethae Pseudopterogorgia rigida Pterogorgia anceps Pterogorgia citrina Pterogorgia guadalupensis Hydroida Dentitheca dendritica Plexauridae Eunicea calyculata Eunicea laciniata Eunicea laxispica Eunicea mammosa Eunicea pallida Eunicea palmeri Eunicea species 1 Eunicea succinea Eunicea tourneforti Muriceopsis bayeriana Muriceopsis flavida Plexaura flexuosa Plexaura homomalla Plexaurella species Plexaurella dichotoma Plexaurella grisea Plexaurella nutans Pseudoplexaura crucis Pseudoplexaura flagellosa Pseudoplexaura porosa Zoanthidae Palythoa caribbaeorum. Photo 1 of The two large species of this genus, G. They are often difficult to distinguish. Both form a lattice of branches, mostly in one plane which may be orientated across the prevailing current.