Caulerpa taxifolia

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Caulerpa taxifolia is a species of green seaweed, an alga of the genus Caulerpa, native to tropical waters of the Pacific Ocean, Indian Ocean, and Caribbean Sea.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The species name taxifolia arises from the resemblance of its leaf-like fronds<ref name="isg">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> to those of the yew (Taxus). Template:Citation needed

A strain of the species bred for use in aquariums has established non-native populations in waters of the Mediterranean Sea, the United States, and Australia.<ref name="nz">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is one of two species of algae listed in 100 of the World's Worst Invasive Alien Species compiled by the IUCN Invasive Species Specialist Group.<ref name=":0">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

DescriptionEdit

File:Icones of Japanese algae (Pl. CX) (8006303168).jpg

Two illustrations (Fig 1 . 4-5) of C. taxifolia displaying its "leaf" and rhizome structures (Fig 1 . 1-3 are illustrations of C. sertularioides)

C. taxifolia is light green<ref name="isg" /> with stolons (stems) on the sea floor, from which sparsely-branched upright fronds of approximately 20–60 cm (8–24 in) in height arise.<ref name="weedsau">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Algae in the genus Caulerpa synthesize a mixture of toxins<ref>Template:Cite journal</ref> termed caulerpicin, believed to impart a peppery taste to the plants.<ref>Template:Cite journal</ref> The effects of the specific toxin synthesized by C. taxifolia, caulerpenyne, have been studied,<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> with extracts from C. taxifolia being found to negatively affect P-glycoprotein-ATPase in the sea sponge G. cydonium.<ref>Template:Cite book</ref>

Like all members of the genus Caulerpa, C. taxifolia consists of a single cell with many nuclei. The algae has been identified as the largest known single-celled organism.<ref>Template:Cite journal</ref> Wild-type C. taxifolia is monoecious.<ref name="reproduction">Template:Cite journal</ref>

Use in aquariaEdit

Caulerpa species are commonly used in aquaria for their aesthetic qualities and ability to control the growth of undesired species.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> C. taxifolia has been cultivated for use in aquaria in western Europe since the early 1970s.<ref name="researchgate">Template:Cite journal</ref> A clone of the alga that was resistant to cold was observed in the tropical aquarium at the Wilhelma Zoo in Stuttgart<ref name="nova">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and further bred by exposure to chemicals and ultraviolet light.<ref name="factsheet">Template:Cite journal</ref> The zoo distributed the strain to other aquaria, including the Oceanographic Museum of Monaco.<ref name="nova" />

The aquarium strain is morphologically identical to native populations of the species.<ref name="isg" /> However, a 2008 study found that a population of the aquarium strain near Caloundra, Australia exhibited markedly reduced sexual reproduction, with only male plants present during some reproductive episodes.<ref name="reproduction" /> The aquarium strain can survive out of water for up to 10 days in moist conditions, with 1 cm fragments capable of producing viable plants.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Status as invasive speciesEdit

Outside its native range, C. taxifolia is listed as an invasive species.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It is one of two algae on the list of the world's 100 worst invasive species compiled by the IUCN Invasive Species Specialist Group (alongside Wakame).<ref name=":0" /> The species is able to thrive in heavily polluted waters,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> possibly contributing to its spread in the Mediterranean.<ref>Template:Cite journal</ref>

Presence in the Mediterranean SeaEdit

The presence of C. taxifolia in the Mediterranean was first reported in 1984<ref name="springer">Template:Cite journal</ref> in an area adjacent to the Oceanographic Museum of Monaco.<ref name="noaafisheries">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Alexandre Meinesz, a marine biologist, attempted to alert Moroccan and French authorities to the spread of the strain in 1989,<ref name="nova" /> but the governments failed to respond to his concerns.<ref name="guardian">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The occurrence of the strain is generally believed to be due to an accidental release by the museum,<ref name="isg" /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> but Monaco rejected the attribution and instead claimed that the observed algae was a mutant strain of C. mexicana.<ref name="guardian" /> By 1999, scientists agreed that it was no longer possible to eliminate the presence of C. taxifolia in the Mediterranean.<ref name="guardian" />

A study published in 2002 found that beds of Posidonia oceanica in the Bay of Menton were not negatively affected eight years after colonization by C. taxifolia.<ref>Template:Cite journal</ref> Other published studies have shown that fish diversity and biomass are equal or greater in Caulerpa meadows than in seagrass beds<ref>Relini, G., M Relini, and G. Torchia. (1998) Fish biodiversity in a Caulerpa taxifolia meadow in the Ligurian Sea. Italian Journal of Zoology 65 Supplement:465-470.</ref> and that Caulerpa had no effect on composition or richness of fish species.<ref>Template:Cite journal</ref>

Studies in 1998<ref name="researchgate" /> and 2001<ref name="springer" /> found that the strain observed in the Mediterranean was genetically identical to aquarium strains, with similarities to an additional population in Australia.

Presence in AustraliaEdit

A 2007 study found that a native bivalve mollusc species was negatively affected by the presence of C. taxifolia, but that the effect was not necessarily different from that of native seagrass species.<ref>Template:Cite journal</ref> A 2010 study indicated that the effect of detritus from C. taxifolia negatively impacted abundance and species richness.<ref>Template:Cite journal</ref>

Presence in CaliforniaEdit

C. taxifolia was found in waters near San Diego, California, in 2000,<ref>Template:Cite magazine</ref> where chlorine bleach was used in efforts to eradicate the strain.<ref>Template:Cite journal</ref> The strain was declared eradicated from Agua Hedionda Lagoon in 2006.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> California passed a law in 2001 forbidding the possession, sale, transport, or release of Caulerpa taxifolia within the state.<ref name="bill1334">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The Mediterranean clone of C. taxifolia was listed as a noxious weed in 1999<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> by the Animal and Plant Health Inspection Service, prohibiting interstate sale and transport of the strain without a permit under the Noxious Weed Act and Plant Protection Act.<ref name="noaafisheries" /><ref name="weedregs">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Other negative effectsEdit

C. taxifolia may become entangled in fishing gear and boat propellers.<ref name="nz" />

Control methodsEdit

C. taxifolia may be controlled via mechanical removal, poisoning with chlorine, or application of salt.<ref name="weedsau" /> Researchers at the University of Nice investigated possible use of a species of sea slug, Elysia subornata, as a possible natural control method, but found that it was not suitable for use in the Mediterranean due to cold winter water temperatures and insufficient population density.<ref>Template:Cite journal</ref>

GalleryEdit

Caulerpa taxifolia - National Museum of Nature and Science, Tokyo - DSC07620.JPG

C. taxifolia on display at the National Museum of Nature and Science in Tokyo, Japan
CaulerpaTaxifolia.jpg

A field of C. taxifolia amongst seagrass
Lysmata amboinensis on Caulerpa taxifolia.jpg

A Pacific cleaner shrimp (Lysmata amboinensis) on top of a C. taxifolia specimen within a marine aquarium