Limacina antarctica
Encyclopedia
Limacina antarctica is a species
of swimming sea snail
in the family Limacinidae
, which belong to the group commonly known as sea butterflies
(Thecosomata).
Limacina antarctica is a keystone species
of the mesozooplankton of Antarctic
pelagic ecosystems.
Until 2010 this taxon was known only as Limacina helicina antarctica or as Limacina helicina f. antarctica. Limacina antarctica is however now considered to be a separate species from Limacina helicina
, based on cytochrome c oxidase subunit I (COI) gene sequences.
This species occurs in the Weddell Sea
and Ross Sea
in the Antarctic
and in Cumberland Bay
, South Georgia. and other localities in the Southern Ocean
.
.
The width of the shell is 0.5-6 mm.
ic species. It is very abundant in the Southern Ocean, with up to 2681 individuals per m3. This species is abundant in the Ross Sea
, Antarctica. It is sometimes even more abundant than krill
.
Limacina antarctica feeds mainly on phytoplankton
and also on zooplankton
, but less so. It catches its prey using mucus
webs.
This snail is a primary consumer and directly depends on phytoplankton. When the phytoplankton is reduced, the population of Limacina antarctica is also reduced, and it can even disappear as happened in McMurdo Sound
in the summer of 2000-2001. It is considered an indicator species
of the health of the ecosystem. Under different conditions in McMurdo Sound there can be over 300 individuals per m3, which is over 20% of the biomass
of zooplankton
.
Fecal pellets of Limacina antarctica and its quantity have been firstly described by Manno et al. (2010). Fecal pellets are oval, greenish brown and with peritrophic membrane. A size of a single pellet varies from 103 μm (286600 μm3) to 120 μm (440,610 μm3). A single Limacina antarctica produces about 6-11 pellets daily. Population of Limacina antarctica in the studied area in the Ross Sea produced from about 71,000 pellets per square meter per year to about 362,000 pellets per square meter per year. Fecal pellets of Limacina antarctica has contributed to about 19% of flux of organic carbon. Fecal pellets of Limacina antarctica together with dead Limacina antarctica can cover up to 72% (estimation) of organic carbon flux
to the deep water.
Limacina antarctica probably affect carbon cycle
, resources of phytoplankton
and dimethyl sulfide
(emission by phytoplankton), that may have impact on the Earth's climate
.
Many predators depend on Limacina antarctica as their food source:
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Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of swimming sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
in the family Limacinidae
Limacinidae
Limacinidae is a family of small sea snails, pteropods, pelagic marine gastropod mollusks in the clade Thecosomata .-Genera:Genera within the family Limacinidae include:...
, which belong to the group commonly known as sea butterflies
Sea butterfly
Sea butterflies, also known as Thecosomata or flapping snails, are a taxonomic suborder of small pelagic swimming sea snails. These are holoplanktonic opisthobranch gastropod mollusks in the informal group Opisthobranchia. They include some of the world's most abundant gastropod species.This group...
(Thecosomata).
Limacina antarctica is a keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
of the mesozooplankton of Antarctic
Antarctic
The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...
pelagic ecosystems.
Until 2010 this taxon was known only as Limacina helicina antarctica or as Limacina helicina f. antarctica. Limacina antarctica is however now considered to be a separate species from Limacina helicina
Limacina helicina
Limacina helicina is a species of small swimming predatory sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies ....
, based on cytochrome c oxidase subunit I (COI) gene sequences.
Distribution
The distribution of Limacina antarctica is circumglobal south of 50°S.This species occurs in the Weddell Sea
Weddell Sea
The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha Coast, Queen Maud Land. To the east of Cape Norvegia is...
and Ross Sea
Ross Sea
The Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
in the Antarctic
Antarctic
The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...
and in Cumberland Bay
Cumberland Bay
Cumberland Bay, wide at its entrance between Larsen and Barff Points, which separates into two extensive arms that recede inland along the northern coast of South Georgia. Discovered and named in 1775 by a British expedition under James Cook....
, South Georgia. and other localities in the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
.
Description
Limacina antarctica has a sinistral and very thin shell. Its thickness is approximately 2–9 μm. There are ribs on the surface of the shell. There are differences in the shell structure between Limacina antarctica and Limacina helicinaLimacina helicina
Limacina helicina is a species of small swimming predatory sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies ....
.
The width of the shell is 0.5-6 mm.
Ecology
Limacina antarctica is a holoplanktonHoloplankton
Holoplankton are organisms that are planktonic for their entire life cycle. Examples of holoplankton include some diatoms, radiolarians, some dinoflagellates, foraminifera, amphipods, krill, copepods, and salps.-Sources:Asexual Holoplankton:...
ic species. It is very abundant in the Southern Ocean, with up to 2681 individuals per m3. This species is abundant in the Ross Sea
Ross Sea
The Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
, Antarctica. It is sometimes even more abundant than krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
.
Limacina antarctica feeds mainly on phytoplankton
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
and also on zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
, but less so. It catches its prey using mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
webs.
This snail is a primary consumer and directly depends on phytoplankton. When the phytoplankton is reduced, the population of Limacina antarctica is also reduced, and it can even disappear as happened in McMurdo Sound
McMurdo Sound
The ice-clogged waters of Antarctica's McMurdo Sound extend about 55 km long and wide. The sound opens into the Ross Sea to the north. The Royal Society Range rises from sea level to 13,205 feet on the western shoreline. The nearby McMurdo Ice Shelf scribes McMurdo Sound's southern boundary...
in the summer of 2000-2001. It is considered an indicator species
Indicator species
An indicator species is any biological species that defines a trait or characteristic of the environment. For example, a species may delineate an ecoregion or indicate an environmental condition such as a disease outbreak, pollution, species competition or climate change...
of the health of the ecosystem. Under different conditions in McMurdo Sound there can be over 300 individuals per m3, which is over 20% of the biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
of zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
.
Fecal pellets of Limacina antarctica and its quantity have been firstly described by Manno et al. (2010). Fecal pellets are oval, greenish brown and with peritrophic membrane. A size of a single pellet varies from 103 μm (286600 μm3) to 120 μm (440,610 μm3). A single Limacina antarctica produces about 6-11 pellets daily. Population of Limacina antarctica in the studied area in the Ross Sea produced from about 71,000 pellets per square meter per year to about 362,000 pellets per square meter per year. Fecal pellets of Limacina antarctica has contributed to about 19% of flux of organic carbon. Fecal pellets of Limacina antarctica together with dead Limacina antarctica can cover up to 72% (estimation) of organic carbon flux
Carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth...
to the deep water.
Limacina antarctica probably affect carbon cycle
Carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth...
, resources of phytoplankton
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
and dimethyl sulfide
Dimethyl sulfide
Dimethyl sulfide or methylthiomethane is an organosulfur compound with the formula 2S. Dimethyl sulfide is a water-insoluble flammable liquid that boils at and has a characteristic disagreeable odor. It is a component of the smell produced from cooking of certain vegetables, notably maize,...
(emission by phytoplankton), that may have impact on the Earth's climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
.
Many predators depend on Limacina antarctica as their food source:
- The gastropod Clione antarcticaClione antarcticaClione antarctica is a species of a pelagic marine gastropod mollusks in the family Clionidae.- Distribution :Distribution of Clione antarctica include Southern Hemisphere in polar waters of Antarctica.- Ecology :...
feeds only on Limacina antarctica. There is a coevolutionary relationship between this specilized predator and its prey; their life cycles are parallel. - The medusae Solmundella bitentaculataSolmundella bitentaculataSolmundella bitentaculata is a species of narcomedusa jellyfish in the family Aeginidae.-Distribution:This species is found in:* Ross Sea, Antarctica.* European waters * Gulf of Mexico * Kenya * New Zealand * North West Atlantic...
and Diplulmaris antarcticaDiplulmaris antarcticaDiplulmaris antarctica is a species of jellyfish in the family Ulmaridae.-Distribution:This species is found in Antarctica including the Antarctic Peninsula in continental shelf waters near the surface.-Description:...
- Fish in the family Myctophidae heavily depend on Limacina antarctica. Limacina sp. is a food species for a number of myctophid fishes in the Southern Ocean: Electrona antarctica, Electrona paucirastraElectrona paucirastraElectrona paucirastra is a lanternfish in the family Myctophidae, found around the globe in the southern hemisphere between 35° S and 48° S. Its length is about 7 cm. It is a mesopelagic species, which can be found close to surface at night-time....
, Electrona subaspera, Metelectrona herwigi, Protomyctophum normani, Diaphus taaningi, Diaphus hudsoni, Gymnoscopelus nicholsi, Ceratoscopelus warmingii and Symbolophorus boops. - Also notothenioid fish (family NototheniidaeNototheniidaeThe cod icefishes or nothothens are the family Nototheniidae of acanthopterygian fishes, containing about 50 species in 13 genera. They are traditionally placed in the perciform assemblage together with their relatives, but like every lineage in the "Perciformes" their actual relationships are not...
) heavily depend on Limacina antarctica as food. For example fishes: Trematomus newnesi, Trematomus bernacchii, Trematomus hansoni, Trematomus centronotus and Pagothenia borchgrevink. - Whales heavily depend on this species
External links
- Map of distribution of Limacina antarctica at Marine Species Identification Portal.
