View source for Pyrosome

{{Short description|Family of tunicates}}
{{Automatic taxobox
| name = Pyrosomatidae
| fossil_range = {{Fossil range|Neogene|Present}}
| image = Pyrosoma atlanticum.JPG
| image_caption = ''[[Pyrosoma atlanticum]]''
| parent_authority = Jones, 1848<ref>{{Catalogue of Life|id=B6LN9|title=Pyrosomatida|access-date=29 September 2024}}</ref>
| taxon = Pyrosomatidae
| authority = [[Fernando Lahille|Lahille]], 1888
| subdivision_ref = <ref name=WoRMS-family/>
| subdivision_ranks = Genera
| subdivision = *''[[Pyrosoma]]'' <small>[[François Péron|Péron]], 1804</small><ref name=WoRMS-genus>{{cite taxon |WoRMS|id=137224 |title=''Pyrosoma'' Péron, 1804 |access-date=20 September 2024}}</ref>
*''[[Pyrosomella]]'' <small>van Soest, 1979</small>
*''[[Pyrostremma]]'' <small>Garstang, 1929</small>
}}
'''Pyrosomes''' are free-floating colonial [[tunicate]]s in family '''Pyrosomatidae'''. There are three genera, ''[[Pyrosoma]]'', ''[[Pyrosomella]]'' and ''[[Pyrostremma]]'', and eight species.<ref name=WoRMS-family>{{cite taxon|WoRMS|title=Pyrosomatidae Lahille, 1888 |id=137216 |access-date=29 September 2024}}</ref><ref name=Lilly2023>{{cite journal |first1=Laura E. |last1=Lilly  |first2=Iain M. |last2=Suthers  |first3=Jason D. |last3=Everett  |first4=Anthony J. |last4=Richardson |year=2023 |title=A global review of pyrosomes: Shedding light on the ocean's elusive gelatinous "fire-bodies". |journal=Limnol. Oceanogr. Lett. |volume=8 |issue=6 |pages=812–829 |doi=10.1002/lol2.10350 |doi-access=free |bibcode=2023LimOL...8..812L }}</ref> They usually live in the upper layers of the open ocean in warm seas, although some may be found at greater depths.<ref name=Lilly2023 />
Pyrosomes form cylindrical or cone-shaped colonies up to {{cvt|60|ft|m|order=flip}} long,<ref name=Atlantic>{{cite news |last= Garber|first= Megan|date= August 2, 2013|title= 12 Reasons Pyrosomes Are My New Favorite Terrifying Sea Creatures|url= https://www.theatlantic.com/technology/archive/2013/08/12-reasons-pyrosomes-are-my-new-favorite-terrifying-sea-creatures/278316/|work= The Atlantic}}</ref> made up of hundreds to thousands of individuals, known as [[zooid]]s. [[Colony (biology)|Colonies]] range in size from less than one centimeter to several metres in length. They are commonly called "sea pickles".<ref name="blobs">{{Cite web |url=http://www.newser.com/story/244630/blob-like-intruders-infesting-pacific-coast.html |title=Blob-like intruders infesting pacific coast|date=22 June 2017 }}</ref><ref name="blob2">{{Cite web |url=http://www.newsweek.com/mysterious-sea-pickles-invading-west-coast-bizarre-bloom-628338 |title=Newsweek: Mysterious Sea Pickles invading West Coast in bizarre bloom|website=[[Newsweek]] |date=22 June 2017 }}</ref> Other nicknames include "sea worms", "sea squirts", "fire bodies", and "cockroaches of the sea".<ref name=NatGeo />
Each zooid is a few millimetres in size, but is embedded in a common gelatinous tunic that joins all of the individuals.<ref name="blobs" /> Each zooid opens both to the inside and outside of the "tube", drawing in ocean water from the outside to its internal filtering mesh called the branchial basket, extracting the microscopic plant cells on which it feeds, and then expelling the filtered water to the inside of the cylinder of the colony. The colony is bumpy on the outside, each bump representing a single zooid, but nearly smooth, although perforated with holes for each zooid, on the inside.<ref name=Atlantic /><ref name=NatGeo />
Pyrosomes are [[plankton]]ic, which means their movements are largely controlled by currents, tides, and waves in the oceans. On a smaller scale, however, each colony can move itself slowly by the process of jet propulsion, created by the coordinated beating of [[cilia]] in the branchial baskets of all the zooids, which also create feeding currents.<ref name=NatGeo>{{cite news |last= Guo|first= Demi|date= February 20, 2019|title= See the giant 'sea worm' filmed off the coast of New Zealand|url= https://www.nationalgeographic.com/animals/2019/02/giant-sea-worm-pyrosome-sighted-new-zealand/|archive-url= https://web.archive.org/web/20190220232656/https://www.nationalgeographic.com/animals/2019/02/giant-sea-worm-pyrosome-sighted-new-zealand/|url-status= dead|archive-date= February 20, 2019|work= National Geographic}}</ref>
Pyrosomes are brightly [[bioluminescence|bioluminescent]], flashing a pale blue-green light that can be seen for many tens of metres.  Pyrosomes are closely related to [[salp]]s, and are sometimes called "fire salps". Sailors on the ocean occasionally observe calm seas containing many pyrosomes, all luminescing on a dark night.<ref name=Atlantic /><ref name=NatGeo />
Pyrosomes feed through filtration and they are among the most efficient filter feeders of any zooplankton species.<ref>{{Cite journal|last1=Henschke|first1=Natasha|last2=Pakhomov|first2=Evgeny A.|last3=Kwong|first3=Lian E.|last4=Everett|first4=Jason D.|last5=Laiolo|first5=Leonardo|last6=Coghlan|first6=Amy R.|last7=Suthers|first7=Iain M.|date=May 2019|title=Large vertical migrations of ''Pyrosoma atlanticum'' play an important role in active carbon transport |journal=Journal of Geophysical Research: Biogeosciences|language=en|volume=124|issue=5|pages=1056–1070|doi=10.1029/2018JG004918 |doi-access=free|bibcode=2019JGRG..124.1056H |hdl=10453/139295|hdl-access=free}}</ref>
==Etymology==
The name ''Pyrosoma'' derives from the Greek words ''pyro'', meaning "fire", and ''soma'', meaning "body".
==Bioluminescence==
Although many planktonic organisms are bioluminescent, pyrosome bioluminescence is unusual in its brilliance and sustained light emission,<ref name=Bowlby>{{cite journal |last1=Bowlby |first1=M.R. |first2=E.A. |last2=Widder |first3=J.F. |last3=Case |year=1990 |title=Patterns of stimulated bioluminescence in two pyrosomes (Tunicata: Pyrosomatidae) |journal=Biological Bulletin |volume=179 |pages=340–350 |doi=10.2307/1542326 |pmid=29314963 |issue=3 |publisher=Marine Biological Laboratory |jstor=1542326|url=https://www.biodiversitylibrary.org/part/24992 }}</ref> and evoked the following comment when seen by the eminent scientist [[Thomas Henry Huxley|Thomas Huxley]] at sea:<blockquote>"I have just watched the moon set in all her glory, and looked at those lesser moons, the beautiful Pyrosoma, shining like white-hot cylinders in the water" (T.H.&nbsp;Huxley, 1849).<ref name=Huxley>{{cite book |editor-last=Huxley |editor-first=J. |editor-link=Julian Huxley |title=T.H. Huxley's diary of the voyage of H.M.S. Rattlesnake |author-first=T.H. |author-last=Huxley |author-link=Thomas Henry Huxley |publisher=Doubleday |location=Garden City, New York |year=1936}}</ref></blockquote>
[[File:Pyrosoma 001.png|thumb|Section through the wall of a pyrosome (magnified) showing a single layer of ascidiozooids: (br)&nbsp;branchial orifice; (at)&nbsp;atrial orifice; (tp)&nbsp;process of the test; (br&nbsp;s)&nbsp;branchial sac]]
Pyrosomes often exhibit waves of light passing back and forth through the colony, as each individual zooid detects light and then emits light in response. Each zooid contains a pair of light organs located near the outside surface of the tunic, which are packed with luminescent organelles that may be intracellular bioluminescent bacteria. The waves of bioluminescence that move within a colony are apparently not propagated by [[neuron]]s, but by a [[Photon|photic stimulation]] process.<ref>{{cite journal |author1=Mackie, G.O. |author2=Bone, Q. |year=1978 |title=Luminescence and associated effector activity in ''Pyrosoma'' (Tunicata: Pyrosomida) |journal=[[Proceedings of the Royal Society B]] |volume=202 |pages=483–495 |doi=10.1098/rspb.1978.0081 |issue=1149|bibcode=1978RSPSB.202..483M |s2cid=84706130 }}</ref> Flashing zooids not only stimulate other zooids within the colony to luminesce, but nearby colonies will also display bioluminescence in response. Colonies will luminesce in response to touch, as well as to light.<ref name=Bowlby/>
==Taxonomy==
[[File:Pyrosoma atlanticum (12256).jpg|thumb|''Pyrosoma atlanticum'' by a tide pool in California]]
According to the [[World Register of Marine Species]], the family is divided into two subfamilies and three genera, containing eight species.<ref name=WoRMS-family/>
* Subfamily [[Pyrosomatinae]] <small>Lahille, 1888</small>
** Genus ''[[Pyrosoma]]'' <small>Péron, 1804</small>
*** ''[[Pyrosoma aherniosum]]'' <small>Seeliger, 1895</small>
*** ''[[Pyrosoma atlanticum]]'' <small>Péron, 1804</small>
*** ''[[Pyrosoma godeauxi]]'' <small>van Soest, 1981</small>
*** ''[[Pyrosoma ovatum]]'' <small>Neumann, 1909</small>
** Genus ''[[Pyrosomella]]'' <small>van Soest, 1979</small>
*** ''[[Pyrosomella operculata]]'' <small>(Neumann, 1909)</small>
*** ''[[Pyrosomella verticillata]]'' <small>(Neumann, 1909)</small>
* Subfamily Pyrostremmatinae <small>van Soest, 1979</small>
** Genus ''[[Pyrostremma]]'' <small>Garstang, 1929</small>
*** ''[[Pyrostremma agassizi]]'' <small>(Ritter & Byxbee, 1905)</small>
*** ''[[Pyrostremma spinosum]]'' <small>(Herdman, 1888)</small>
==Bloom in North Pacific==
In 2017, pyrosomes were observed to have spread in unprecedented numbers along the [[Pacific Ocean|Pacific]] coast of [[North America]] as far north as [[Alaska]]. The causes remain unknown, but one hypothesis is that this bloom may have resulted in part from unusually warm water along the coast over several preceding years. Scientists were concerned that should there be a massive die-off of the pyrosomes, it could create a huge [[dead zone (ecology)|dead zone]] as the [[decomposition]] of their bodies could consume much of the [[oxygen]] dissolved in the surrounding seawater.<ref name=blobs /><ref name=blob2 /><ref>{{cite web |url=http://www.opb.org/news/article/massive-bloom-of-pickle-shaped-sea-creatures-fills-the-pacific/ |title=''Massive Bloom Of Pickle-Shaped Sea Creatures Fills The Pacific'' |publisher=Oregon Public Radio |accessdate=November 17, 2017}}</ref>
==Pyrosome as prey==
Many type of organisms have been spotted eating pyrosome; so far these organisms are sea turtles, sea birds, different species of fish (their primary source of prey are pyrosomes), sea urchins and crabs{{Citation needed|date=March 2024}}.
==References==
{{Reflist}}
== Bibliography ==
*Bone, Q. editor (1998) The Biology of Pelagic Tunicates. Oxford University Press, Oxford. 340 pp.
==External links==
{{Commons category|Pyrosoma}}
*{{cite web |title=A 'sea pickle'? An animal that can grow to 60 feet long is washing up on the Oregon coast |date=1 Feb 2022 |author=Jordan Mendoza |website=USA Today |url=https://www.usatoday.com/story/news/nation/2022/02/01/sea-pickle-washing-up-oregon-beaches/9230497002/}}
*[https://web.archive.org/web/20120216134956/http://www.mar-eco.no/mareco_news/2004/the_pyrosome_story Huge pyrosome captured in the North Atlantic - story and images]
*[http://www.divebums.com/FishID/Pages/pyrosoma_atlanticum.html Images taken by divers off southern California]
*[http://www.lifesci.ucsb.edu/~biolum/ The Bioluminescence Web Page]
*[https://web.archive.org/web/20180616020914/https://nerdist.com/pyrosomes-are-the-borg-of-the-oceans/ Divers with huge southern hemisphere pyrosomes]
*[http://www.cbc.ca/news/canada/british-columbia/tropical-sea-creatures-blooming-bc-1.4164883/ Millions of tropical sea creatures invade waters off B.C. coast]
*[https://www.fisheries.noaa.gov/feature-story/researchers-investigate-explosion-number-pyrosomes-alaska/ Researchers Investigate Explosion in the Number of Pyrosomes off Alaska]
* {{Cite web
|title=The 60 foot long jet powered animal you've probably never heard of
|author=R R Helm
|date=1 August 2013
|publisher=Deep Sea News
|url=http://deepseanews.com/2013/08/the-60-foot-long-jet-powered-animal-youve-probably-never-heard-of/
}}
{{Taxonbar|from1=Q4913878|from2=Q11847380}}
[[Category:Pyrosomatidae| ]]