Pyrosoma atlanticum

''Pyrosoma atlanticum'' is a pelagic species of marine colonial tunicate in the class Thaliacea found in temperate waters worldwide. The name of the genus comes from the Greek words ''pyros'' meaning 'fire' and ''soma'' meaning 'body', referring to the bright bioluminescence sometimes emitted.''Pyrosoma atlanticum'' (Peron, 1804) : Pyrosome
The JelliesZone. Retrieved 2011-11-10. The specific epithet ''atlanticum'' refers to the Atlantic Ocean, from where the first specimen of the species was collected for scientific description; it was described in 1804 by François Péron, a French naturalist.

Description

A colony of ''P. atlanticum'' is cylindrical and can grow up to long and wide. The constituent zooids 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 slits. Along the side of the branchial sac runs the endostyle, which produces mucus filters. Water is moved through the gill slits into the centre of the cylinder by cilia pulsating rhythmically. Plankton 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 comparing different zooplankton 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 in the organism's transcriptome homologous to ''Renilla'' luciferase (RLuc). Further study of the luciferase showed that it reacted with coelenterazine to produce light, much like RLuc.

Ecology

Five specimens of the penaeid shrimp '' Funchalia'' were found living inside colonies of ''P. atlanticum''. Other amphipods also lived there, including the hyperiids ''Phronima'' and '' Phronimella'' spp.

Predators of ''P. atlanticum'' include various bony fishes, such as the spiky oreo, the big-eyed cardinalfish, and the pelagic butterfish, dolphins, and whales such as the sperm whale and giant beaked whale.

Synonyms

* ''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

See also

* Jelly-falls

References

External links

*

{{Taxonbar, from=Q4927517

Thaliacea
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