''Pyrosoma atlanticum'' is a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of marine colonial

tunicate Tunicates are marine invertebrates belonging to the subphylum Tunicata ( ). This grouping is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ...

in the class

Thaliacea Thaliacea is a class of marine chordates within the subphylum Tunicate, Tunicata, comprising the salps, pyrosomes and doliolids. Unlike their benthic relatives the Ascidiacea, ascidians, from which they are believed to have emerged, thaliaceans a ...

found in temperate waters worldwide. The name of the genus comes from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words ''pyros'' meaning 'fire' and ''soma'' meaning 'body', referring to the bright

bioluminescence Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorgani ...

sometimes emitted.''Pyrosoma atlanticum'' (Peron, 1804) : Pyrosome
The JelliesZone. Retrieved 2011-11-10. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''atlanticum'' refers to the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

, from where the first specimen of the species was collected for scientific description; it was described in 1804 by

François Péron François Auguste Péron (22 August 1775 – 14 December 1810) was a French naturalist and explorer. Life Péron was born in Cérilly, Allier, in 1775, the son of a tailor (not a harness maker as is frequently asserted). Although intended fo ...

, a French naturalist.

Description

A colony of ''P. atlanticum'' is cylindrical and can grow up to long and wide. The constituent

zooid A zooid or zoöid is an animal that is part of a colonial animal. This lifestyle has been adopted by animals from separate unrelated taxa. Zooids are multicellular; their structure is similar to that of other solitary animals. The zooids can ...

s form a rigid tube, which may be pale pink, yellowish, or bluish. One end of the tube is narrower and is closed, while the other is open and has a strong diaphragm. The outer surface or test is gelatinised and dimpled with backward-pointing, blunt processes. The individual zooids are up to long and have a broad, rounded branchial sac with

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

slits. Along the side of the branchial sac runs the

endostyle The endostyle is an organ found in invertebrate chordate species of tunicates, lancelets, and in the larval stage of vertebrate lampreys. It assists in filter-feeding. It has evolved into the thyroid in vertebrate chordates. Since the endo ...

, which produces

mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...

filters. Water is moved through the gill slits into the centre of the cylinder by

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

pulsating rhythmically.

Plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

and other food particles are caught in mucus filters in the processes as the colony is propelled through the water. ''P. atlanticum'' is bioluminescent and can generate a brilliant blue-green light when stimulated.''Pyrosoma atlanticum''
Marine Species Identification Portal. Retrieved 2011-11-11.

Distribution and habitat

''P. atlanticum'' is found in temperate waters in all the world's oceans, usually between 50°N and 50°S. It is most plentiful at depths below 250 m (800 ft).''Pyrosoma atlanticum'' - Péron, 1804
SeaLifeBase. Retrieved 2011-11-11. Colonies are pelagic and move through the water column. They undergo a large diurnal migration, rising toward the surface in the evening and descending around dawn. Large colonies may rise through a vertical distance of 760 m (2,500 ft) daily, and even small colonies a few millimetres long can cover vertical distances of 90 m (300 ft).

Biology

A study in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

comparing different

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

organisms found that colonies of ''P. atlanticum'' were the most efficient grazers of particles above 10 μm in diameter, catching a higher proportion of the particles than other grazers. This implies the species uses high biomass intake as a strategy, rather than investing in energy-conservation mechanisms. Growth occurs by new rings of zooids being budded off around the edge of the elongating colony. A pair of luminescent organs is on either side of the inlet siphon of each zooid. When stimulated, these turn on and off, causing rhythmic flashing. No neural pathway runs between the zooids, but each responds to the light produced by other individuals, and even by light from other nearby colonies. ''P. atlanticum'' remains as one of the least studied planktonic grazers, according to a 2021 study. In the study, the researchers took samples of the pyrosome's microbiome. The results of the study found that a possible source of bioluminescence in ''P. atlanticum'' is the abundance of '' Photobacterium'' in its microbiome. However, there is still debate, as a 2020 study found a potential endogenous pyrosome

luciferase Luciferase is a generic term for the class of oxidative enzymes that produce bioluminescence, and is usually distinguished from a photoprotein. The name was first used by Raphaël Dubois who invented the words ''luciferin'' and ''luciferase'' ...

in the organism's transcriptome homologous to ''Renilla'' luciferase (RLuc). Further study of the luciferase showed that it reacted with

coelenterazine Coelenterazine is a luciferin, a molecule that emits light after reaction with oxygen, found in many aquatic organisms across eight phyla. It is the substrate of many luciferases such as '' Renilla reniformis'' luciferase (Rluc), ''Gaussia'' lu ...

to produce light, much like RLuc.

Ecology

Five specimens of the penaeid shrimp ''

Funchalia ''Funchalia'' is a genus of deep-water prawns of the family Penaeidae. Six species are currently recognised: *''Funchalia danae'' Burkenroad, 1940 *'' Funchalia meridionalis'' (Lenz & Strunck, 1914) *''Funchalia sagamiensis'' Fujino, 1975 *''Func ...

'' were found living inside colonies of ''P. atlanticum''. Other

amphipods Amphipoda () is an order (biology), order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods () range in size from and are mostly detritivores or scavengers. There are more than 10,700 amphip ...

also lived there, including the hyperiids '' Phronima'' and '' Phronimella'' spp.

Predators Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

of ''P. atlanticum'' include various bony fishes, such as the spiky oreo, the big-eyed cardinalfish, and the pelagic butterfish,

dolphin A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...

s, and

whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...

s such as the

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the Genus (biology), genus ''Physeter'' and one of three extant species in the s ...

and giant beaked whale.

Synonyms

The following synonyms have been noted: * ''Dipleurosoma ellipticum'' Brooks, 1906 – genus transfer and junior synonym * ''Pyrosoma atlanticum dipleurosoma'' Metcalf & Hopkins, 1919 – junior synonym * ''Pyrosoma atlanticum echinatum'' Metcalf & Hopkins, 1919 – junior synonym * ''Pyrosoma atlanticum'' f. ''elegans'' Lesueur, 1815 – junior synonym * ''Pyrosoma atlanticum hawaiiense'' Metcalf & Hopkins, 1919 – junior synonym * ''Pyrosoma atlanticum intermedium'' Metcalf & Hopkins, 1919 – junior synonym * ''Pyrosoma atlanticum paradoxum'' Metcalf & Hopkins, 1919 – junior synonym * ''Pyrosoma atlanticum triangulum'' Neumann, 1913 – junior synonym * ''Pyrosoma atlanticum'' var. ''giganteum'' Lesueur, 1815 – junior synonym * ''Pyrosoma atlanticum'' var. ''levatum'' Seeliger, 1895 – junior synonym * ''Pyrosoma atlanticum'' var. ''tuberculosum'' Seeliger, 1895 – junior synonym * ''Pyrosoma benthica'' Monniot C. & Monniot F., 1966 – junior synonym * ''Pyrosoma elegans'' Lesueur, 1813 – junior synonym * ''Pyrosoma ellipticum'' (Brooks, 1906) – junior synonym * ''Pyrosoma giganteum'' Lesueur, 1815 – junior synonym * ''Pyrosoma giganteum'' var. ''atlanticum'' Péron, 1804 – status change * ''Pyrosoma rufum'' Quoy & Gaimard, 1824 – junior synonym * ''Pyrosoma triangulum'' Neumann, 1909 – junior synonym

References

External links

* {{Taxonbar, from=Q4927517 Pyrosomatidae Fauna of the Atlantic Ocean Fauna of the Indian Ocean Fauna of the Pacific Ocean Bioluminescent animals Animals described in 1804 Taxa named by François Péron Colonial animals