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. The species name taxifolia arises from the resemblance of its leaf-like fronds to those of the yew (Taxus).

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. 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.

Description

thumb|left|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 Algae in the genus Caulerpa synthesize a mixture of toxins termed caulerpicin, believed to impart a peppery taste to the plants. The effects of the specific toxin synthesized by C. taxifolia, caulerpenyne, have been studied, with extracts from C. taxifolia being found to negatively affect P-glycoprotein-ATPase in the sea sponge G. cydonium.

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. Wild-type C. taxifolia is monoecious.

Use in aquaria

Caulerpa species are commonly used in aquaria for their aesthetic qualities and ability to control the growth of undesired species. C. taxifolia has been cultivated for use in aquaria in western Europe since the early 1970s. A clone of the alga that was resistant to cold was observed in the tropical aquarium at the Wilhelma Zoo in Stuttgart and further bred by exposure to chemicals and ultraviolet light. The zoo distributed the strain to other aquaria, including the Oceanographic Museum of Monaco.

Status as invasive species

Outside its native range, C. taxifolia is listed as an invasive species. 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). possibly contributing to its spread in the Mediterranean.

Presence in the Mediterranean Sea

The presence of C. taxifolia in the Mediterranean was first reported in 1984 in an area adjacent to the Oceanographic Museum of Monaco. Alexandre Meinesz, a marine biologist, attempted to alert Moroccan and French authorities to the spread of the strain in 1989, The occurrence of the strain is generally believed to be due to an accidental release by the museum, but Monaco rejected the attribution and instead claimed that the observed algae was a mutant strain of C. mexicana. Other published studies have shown that fish diversity and biomass are equal or greater in Caulerpa meadows than in seagrass beds and that Caulerpa had no effect on composition or richness of fish species.

Studies in 1998 A 2010 study indicated that the effect of detritus from C. taxifolia negatively impacted abundance and species richness.

Presence in California

C. taxifolia was found in waters near San Diego, California, in 2000, where chlorine bleach was used in efforts to eradicate the strain. The strain was declared eradicated from Agua Hedionda Lagoon in 2006. California passed a law in 2001 forbidding the possession, sale, transport, or release of Caulerpa taxifolia within the state.

The Mediterranean clone of C. taxifolia was listed as a noxious weed in 1999 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.

Other negative effects

C. taxifolia may become entangled in fishing gear and boat propellers.

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File: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

File:CaulerpaTaxifolia.jpg|A field of C. taxifolia amongst seagrass

File:Lysmata amboinensis on Caulerpa taxifolia.jpg|A Pacific cleaner shrimp (Lysmata amboinensis) on top of a C.&nbsp;taxifolia specimen within a marine aquarium

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See also

  • Largest organisms

References

Further reading

  • Theodoropoulos, David. 2003. Invasion Biology: Critique of a Pseudoscience. pages 42,159. Avvar Books, Blythe, CA. 237 p.
  • Killer Algae, 2001 BBC Documentary
  • In-depth article on invasions of Caulerpa taxifolia, source as escaped aquarium plant, etc.
  • Caulerpa Taxifolia fact sheet
  • An excerpt from Killer Algae by Alexandre Meinesz
  • Caulerpa taxifolia at the Center for Invasive Species Research
  • "Deep Sea Invasion" Nova (TV series) broadcast April 1, 2003
  • Species Profile- Caulerpa, Mediterranean Clone (Caulerpa taxifolia), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Caulerpa, Mediterranean Clone.