Gorgonian 2493583 223436066 2008-07-04T01:57:21Z Vinny Burgoo 5185868 /* Anatomy */ Spelling: "climactic" --> "climatic" {{Redirect|Gorgonia|the Byzantine saint|Saint Gorgonia}} {{Taxobox | name = Gorgonian | image = Iciligorgia schrammi.jpg | image_width = 250px | image_caption = ''Iciligorgia schrammi'' | regnum = [[Animal]]ia | phylum = [[Cnidaria]] | classis = [[Anthozoa]] | subclassis = [[Alcyonaria]] | ordo = '''Gorgonacea''' | ordo_authority = Lamouroux, 1816 | subdivision_ranks = Suborders and families | subdivision = * [[Holaxonia]] ** [[Acanthogorgiidae]] ** [[Ainigmaptilidae]] ** [[Chrysogorgiidae]] ** [[Ellisellidae]] ** [[Gorgoniidae]] ** [[Ifalukellidae]] ** [[Isididae]] ** [[Keroeididae]] ** [[Paramuriceidae]] ** [[Plexauridae]] ** [[Primnoidae]] * [[Scleraxonia]] ** [[Anthothelidae]] ** [[Briareidae]] ** [[Coralliidae]] ** [[Melithaeidae]] ** [[Paragorgiidae]] ** [[Parisididae]] ** [[Subergorgiidae]] }} A '''gorgonian''', also known as '''sea whip''' or '''sea fan''', is an [[order (biology)|order]] of [[sessile]] [[colony|colonial]] [[cnidaria]]n found throughout the oceans of the world, especially in the [[tropics]] and [[subtropics]]. Gorgonians are similar to the [[sea pen]], another soft coral. Individual tiny [[polyp]]s form a colonies that are normally erect, flattened, branching, and reminiscent of a [[fan (implement)|fan]]. Others may be whiplike, bushy, or even encrusting.<ref name="Borneman">{{cite book | last = Borneman | first = Eric H. | title = Aquarium Corals: Selection, Husbandry, and Natural History | publisher = T.F.H. Publications | date =2001 | location =Neptune City, NJ 07753 | pages = 464 | isbn = 1-890087-47-5}}</ref> 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. == Anatomy == The structure of a gorgonian colony varies. The suborder ''holaxonia'' skeletons are formed from a flexible, horny substance called [[gorgonin]]. The suborder ''scleraxonia'' variety of gorgonians are supported by a skeleton of tightly group calcareous spicules. There are also species which encrust like coral.<ref name="Goldstein">{{cite book | last = Goldstein | first = Robert J. | title = Marine Reef Aquarium Handbook | publisher = Barron's Educational Series, Inc. | date = 1997 | location = | pages = 198 | isbn = 0-8120-9598-7}}</ref> Most of holaxonia and sclerazonia, however, do not attach themselves to a hard substrate. Instead, they anchor themselves in mud or sand. Research has shown that measurements of the gorgonin and calcite within several long-lived species of gorgonians can be useful in [[paleoclimatology]] and [[paleoceanography]], as the skeletal growth rate and composition of these species is highly correlated with seasonal and climatic variation.<ref name="Heikoop">{{cite journal | last =Heikoop | first =J.M. | authorlink = | coauthors = M.J. Risk, C.K. Shearer, V. Atudorei | title = Potential climate signals from the deep-sea gorgonian coral ''Primnoa resedaeformis'' | journal = Hydrobiologia | volume = 471 | issue = 1-3 | pages = 117–124 | date = 2002-03 | doi = 10.1023/A:1016505421115 }}</ref><ref name="Sherwood">{{cite book | last =Sherwood | first =Owen A. | coauthors =Jeffrey M. Heikoop, Daniel J. Sinclair, David B. Scott, Michael J. Risk, Chip Shearer, Kumiko Azetsu-Scott | title =Cold-Water Corals and Ecosystems | publisher =Springer Berlin Heidelberg | date = 2005 | pages =1061-1079 | series = Erlangen Earth Conference Series | doi =10.1007/3-540-27673-4 | isbn = 978-3-540-24136-2 }}</ref><ref name="Bond">{{cite journal | last = Bond | first = Zoë A. | coauthors = Anne L. Cohen, Struan R. Smith, William J. Jenkins | title = Growth and composition of high-Mg calcite in the skeleton of a Bermudian gorgonian (''Plexaurella dichotoma''): Potential for paleothermometry | journal = GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS | volume = 6 | pages =Q08010 | date = 2005-08-31 | doi = 10.1029/2005GC000911 }} </ref> == Ecology == [[Image:Gorgonian.Mgiangrasso.jpg|thumb|left|Purple sea whip gorgonian]]Each gorgonian polyp has eight [[tentacle]]s which catch [[plankton]] and particulate matter that is consumed. This process, called [[filter feeding]], is facilitated when the "fan" is oriented across the prevailing current to maximise water throughput and hence food supply. Some gorgonians contain algae, or [[zooxanthella|zooxanthellae]]. This [[symbiotic|symbiotically]] relationship assists in giving the gorgonian nutrition via [[photosynthesis]]. Gorgonians possessing zooxanthellae are usually characterized by brownish polyps. Those without zooxanthellae usually have more brightly colored polyps. Lacking this additional nutrion, they are more dependent on the nutrition they derive from filter feeding. Gorgonians are found primarily in shallow waters, though some have been found at depths of several thousand feet.<ref name="Borneman"/><ref name="Goldstein"/> The size, shape, and appearance of the gorgonians are highly correlated with their location. The more fan-shaped and flexible gorgonians tend to populate shallower areas with strong currents, while the taller, thinner, and stiffer gorgonians can be found in deeper, calmer waters.<ref name="Borneman"/> Other fauna, such as [[hydrozoa]], [[bryozoa]], and [[brittle stars]], are known to dwell within the branches of gorgonian colonies.<ref name="Haywood">{{cite book | last = Haywood | first =Martyn | coauthors = Sue Wells | title = The Manual of Marine Invertebrates | publisher = Tetra Press:Salamander Books Ltd. | date = 1989 | location = Morris Plains, NJ | pages =208 | isbn = 3-89356-033-5}}</ref> The [[Pygmy seahorse]] not only makes certain species of gorgonians its home, but closely resembles its host and is thus well camoflauged. <ref name="Fishbase">{{cite web | last = Agbayani | first = Eli | title = "Hippocampus bargibanti, Pygmy seahorse" | publisher = FishBase | date = 2007-06-05 | url = http://www.fishbase.org/Summary/SpeciesSummary.php?id=53790 | accessdate = 2007-09-22}} </ref> Gorgonians are classified in the [[phylum (biology)|phylum]] [[Cnidaria]], class [[Anthozoa]], alongside the orders Alcyonacea (soft corals) and [[Pennatulacea]] (sea pens). There are about 500 different species of gorgonians found in the oceans of the world, primarily in the shallow waters of the Atlantic near Florida, Bermuda, and the West Indies.<ref name="UD">{{cite web | title = Sea Fan | publisher = University of Delaware Graduate College of Marine Studies | date = | url = http://www.ocean.udel.edu/kiosk/gorgonia.html | accessdate = 2007-09-23 }}</ref> ==References== <references/> * Sprung & Delbeek (1997), ''The Reef Aquarium'', p. 31-32 ==External links== * [http://www.seawater.no/fauna/Nesledyr/hornkorall.htm The Marine Fauna Gallery of Norway] * [http://animaldiversity.ummz.umich.edu/site/accounts/classification/Gorgonacea.html AnimalDiversity] {{Wikispecies|Gorgonacea}} [[Category:Anthozoa]] [[de:Gorgonien]] [[es:Gorgonacea]] [[fr:Gorgonacea]] [[it:Gorgonacea]] [[nl:Hoornkoralen]] [[sk:Vejárovníky]]