''Caulerpa taxifolia'' is a species of green
seaweed, an
alga
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
of the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''
Caulerpa
''Caulerpa'' is a genus of seaweeds in the family Caulerpaceae (among the green algae). They are unusual because they consist of only one cell with many nuclei, making them among the biggest single cells in the world. A species in the Mediterran ...
'', native to tropical waters of the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...
,
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
, and
Caribbean Sea
The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...
. 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 Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
, the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
, 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
''C. taxifolia'' is light green
with
stolons (stems) on the sea floor, from which sparsely-branched upright fronds of approximately 20–60 cm in height arise.
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
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through th ...
''G. cydonium''.
Like all members of the genus ''Caulerpa,'' ''C. taxifolia'' consists of a single
cell
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...
with many
nuclei. The algae has been identified as the largest known
single-celled organism
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms an ...
. 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
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
since the early 1970s.
A clone of the alga that was resistant to cold was observed in the tropical aquarium at the Wilhelmina Zoo in
Stuttgart and further bred by exposure to chemicals and
ultraviolet light
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
.
The zoo distributed the strain to other aquaria, including the
Oceanographic Museum of Monaco
The Oceanographic Museum (''Musée océanographique'') is a museum of marine sciences in Monaco-Ville, Monaco.
This building is part of the Institut océanographique, which is committed to sharing its knowledge of the oceans.
History
Th ...
.
The aquarium strain is morphologically identical to native populations of the species.
However, a 2008 study found that a population of the aquarium strain near
Caloundra
Caloundra ( ) is a coastal town and the southernmost town in the Sunshine Coast Region in South East Queensland, Australia.
Geography
Caloundra is north of the Brisbane central business district. Caloundra is accessible from Landsborough ...
, Australia exhibited markedly reduced sexual reproduction, with only male plants present during some reproductive episodes.
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.
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
100 of the World's Worst Invasive Alien Species is a list of invasive species compiled in 2014 by the Global Invasive Species Database, a database of invasive species around the world. The database is run by the Invasive Species Specialist Group ...
compiled by the
IUCN Invasive Species Specialist Group.
The species is able to thrive in heavily polluted waters, 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
Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifi ...
, attempted to alert Moroccan and French authorities to the spread of the strain in 1989,
but the governments failed to respond to his concerns.
The occurrence of the strain is generally believed to be due to an accidental release by the museum,
but
Monaco
Monaco (; ), officially the Principality of Monaco (french: Principauté de Monaco; Ligurian: ; oc, Principat de Mónegue), is a sovereign city-state and microstate on the French Riviera a few kilometres west of the Italian region of Lig ...
rejected the attribution and instead claimed that the observed algae was a mutant strain of ''C. mexicana''.
By 1999, scientists agreed that it was no longer possible to eliminate the presence of ''C. taxifolia'' in the Mediterranean.
A study published in 2002 found that beds of ''
Posidonia oceanica
''Posidonia oceanica'', commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free f ...
'' in the Bay of
Menton
Menton (; , written ''Menton'' in classical norm or ''Mentan'' in Mistralian norm; it, Mentone ) is a commune in the Alpes-Maritimes department in the Provence-Alpes-Côte d'Azur region on the French Riviera, close to the Italian border.
Me ...
were not negatively affected eight years after colonization by ''C. taxifolia''. 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
and 2001
found that the strain observed in the Mediterranean was genetically identical to aquarium strains, with similarities to an additional population in Australia.
Presence in Australia
A 2007 study found that a native
bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
species was negatively affected by the presence of ''C. taxifolia'', but that the effect was not necessarily different from that of native seagrass species. 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
San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...
,
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
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
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...
in 1999 by the
Animal and Plant Health Inspection Service
The Animal and Plant Health Inspection Service (APHIS) is an agency of the United States Department of Agriculture (USDA) based in Riverdale, Maryland responsible for protecting animal health, animal welfare, and plant health. APHIS is the lead ...
, prohibiting interstate sale and transport of the strain without a permit under the
Noxious Weed Act and
Plant Protection Act
The Plant Protection Act (PPA) (part of ) is a US statute relating to plant pests and noxious weeds introduced in 2000. It is currently codified at 7 U.S.C. 7701 ''et seq''. It consolidates related responsibilities that were previously spread ...
.
Other negative effects
''C. taxifolia'' may become entangled in fishing gear and boat propellers.
Control methods
''C. taxifolia'' may be controlled via mechanical removal, poisoning with
chlorine
Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...
, or application of
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
.
Researchers at the
University of Nice
A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, the ...
investigated possible use of a species of
sea slug
Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary t ...
, ''
Elysia subornata
''Elysia subornata'' is a species of small sea slug, a marine opisthobranch gastropod mollusk in the family Plakobranchidae.
This sea slug resembles a nudibranch, but it is not closely related to that order of gastropods. Instead, it is a sa ...
'', 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.
Gallery
File:Caulerpa taxifolia - National Museum of Nature and Science, Tokyo - DSC07620.JPG, ''C. taxifolia'' on display at the National Museum of Nature and Science
The is in the northeast corner of Ueno Park in Tokyo. The museum has exhibitions on pre-Meiji period, Meiji science in Japan. It is the venue of the taxidermied bodies of the legendary dogs Hachikō and Taro and Jiro. A life-size blue whale mode ...
in Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
, Japan.
File:CaulerpaTaxifolia.jpg, A field of ''C. taxifolia'' amongst seagrass
Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the orde ...
File:Lysmata amboinensis on Caulerpa taxifolia.jpg, A Pacific cleaner shrimp (''Lysmata amboinensis'') on top of a ''C. taxifolia'' specimen within a marine aquarium
A marine aquarium is an aquarium that keeps ocean, marine plants and animals in a contained environment. Marine aquaria are further subdivided by hobbyists into fish only (FO), fish only with live rock (FOWLR), and reef aquarium, reef aquaria. Fi ...
References
Further reading
*
*
* Theodoropoulos, David. 2003. Invasion Biology: Critique of a Pseudoscience. pages 42,159. Avvar Books, Blythe, CA. 237 p.
External links
*
Killer Algae 2001 BBC Documentary
In-depth article on invasions of Caulerpa taxifolia, source as escaped aquarium plant, etc.from ''Killer Algae'' by Alexandre Meinesz
at the Center for Invasive Species Research
"Deep Sea Invasion"''
Nova (TV series)
A nova is an exploding star.
Nova or NOVA may also refer to:
People with the name
Single name
* Nova (singer), a Puerto Rican reggaeton and hip hop singer, part of duo Nova & Jory
* Nova (wrestler), ring name of American pro wrestler Mike Buc ...
'' broadcast April 1, 2003
Species Profile- Caulerpa, Mediterranean Clone (''Caulerpa taxifolia'') National Invasive Species Information Center,
United States National Agricultural Library
The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Located ...
. Lists general information and resources for Caulerpa, Mediterranean Clone.
{{Taxonbar, from=Q310961
taxifolia
Species described in 1817
Algae of India
Biota of the Mediterranean Sea
Flora of the Indian subcontinent
Invasive species
Invasive species in the Mediterranean Sea