''Amphibalanus amphitrite'' is a
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of acorn
barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive ...
in the
Balanidae
The Balanidae comprise a family of barnacles of the order Balanomorpha. As a result of research published in 2021 by Chan et al., the members of the family Archaeobalanidae were merged with this family.
Genera
These genera belong to the family B ...
family. Its common names include the striped barnacle, the purple acorn barnacle and Amphitrite's rock barnacle. It is found in warm and temperate waters worldwide.
Description
''A. amphitrite'' is a medium-sized, cone-shaped
sessile
Sessility, or sessile, may refer to:
* Sessility (motility), organisms which are not able to move about
* Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant
* Sessility (medicine), tumors and polyps that ...
barnacle with distinctive narrow vertical purple or brown stripes. The surface of the test has vertical ribbing. It has a diamond-shaped
operculum protected by a movable lid formed from two triangular plates. It grows to about twenty millimetres in diameter.
Distribution
It is uncertain where ''A. amphitrite'' originated but it may have been in the
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 ...
or southwestern
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 contine ...
as fossils of the species have been found in these regions.
[ It has now spread to most of the warm and temperate seas of the world.
]
Habitat
''A. amphitrite'' is a common coastal and estuarine organism found on hard natural surfaces such as bedrock, boulders, mollusc shells and red mangrove Red mangrove may refer to at least three plant species:
* ''Rhizophora mangle''
* ''Rhizophora mucronata''
* ''Rhizophora stylosa
''Rhizophora stylosa'', the spotted mangrove, red mangrove, small stilted mangrove or stilt-root mangrove, is a tree ...
roots. It is also found on artificial surfaces such as the hulls of ships, pilings and seawalls. It can be very abundant, with over three hundred individual barnacles being recorded on a single oyster (''Crassostrea virginica
The eastern oyster (''Crassostrea virginica'')—also called the Atlantic oyster, American oyster, or East Coast oyster—is a species of true oyster native to eastern North and South America. Other names in local or culinary use include the Wel ...
'').
Biology
''A. amphitrite'' is a model organism for studies of fundamental and applied larval settlement. This is due to its invasive
Invasive may refer to:
*Invasive (medical) procedure
*Invasive species
*Invasive observation, especially in reference to surveillance
*Invasively progressive spread of disease from one organ in the body to another, especially in reference to cance ...
behaviour, its worldwide distribution and the ease with which it can be bred in the laboratory. Its genome
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
has been sequenced.
''A. amphitrite'' is a hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many taxonomic groups of animals (mostly invertebrates) do not have ...
and individuals have both male and female reproductive organs. Sperm is introduced into the mantle cavities of adjacent barnacles through an elongated penis and the fertilised eggs are brooded within the mantle cavity for several months. Free-swimming larvae called nauplii are then released into the water column where they become part of the zooplankton
Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
. In temperate areas, spawning is mainly in the spring and summer but in warmer waters it may continue throughout the year. Individuals can release up to ten thousand eggs per brood and there may be many broods per year. After several moults the last larval stage, the cyprid
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive ...
larva, settles and crawls around looking for a suitable place to cement itself. It does this with a matrix of proteins secreted by the antennae.[
For feeding, ''A. amphitrite'' has specialized paired appendages called cirri. These are used to sieve food particles from the water and transfer them to the mouth. They are oriented perpendicular to the general flow direction of the water and the rates of movement vary with the availability of food so as to maximize particle intake.
''A. amphitrite'' can tolerate low salinity levels in estuaries but appears to need higher levels in order to breed. It can also tolerate temperatures as low as 12 °C but needs temperatures of at least 15 °C to breed which limits its northerly spread.]
Fouling
''A. amphitrite'' is part of the biofouling
Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...
community. The larvae settle out on and colonise the hulls of ships, harbour structures, buoy
A buoy () is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.
Types
Navigational buoys
* Race course marker buoys are used for buoy racing, the most prevalent form of ya ...
s and the inflow pipes of desalination plant
Desalination is a process that takes away mineral components from saline water. More generally, desalination refers to the removal of salts and minerals from a target substance, as in soil desalination, which is an issue for agriculture. Saltw ...
s. These become covered with barnacles and other associated hard fouling species. Metal structures become corroded and maintenance costs are increased. The fouling also causes friction between the water and the hulls of ships and this reduces efficiency and increases fuel costs.[
]
References
{{Taxonbar, from=Q2844158
Barnacles
Crustaceans described in 1854
Taxa named by Charles Darwin