Editing Portuguese man o' war (section)

==Drifting dynamics==
[[File:Bluebottle (Physalia physalis) sail camber.png|thumb|The bluebottle course at zero angle of attack is dependent on the sail camber.<ref name=Lee2021>{{cite journal | last1=Lee | first1=Daniel | last2=Schaeffer | first2=Amandine | last3=Groeskamp | first3=Sjoerd | title=Drifting dynamics of the bluebottle (''Physalia physalis'') | journal=Ocean Science | publisher=Copernicus GmbH | volume=17 | issue=5 | date=October 2021 | issn=1812-0792 | doi=10.5194/os-17-1341-2021 | pages=1341–1351| bibcode=2021OcSci..17.1341L | s2cid=244189437 | doi-access=free }} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License] {{Webarchive|url=https://web.archive.org/web/20171016050101/https://creativecommons.org/licenses/by/4.0/ |date=2017-10-16 }}.</ref>]]
''P. physalis'' uses a float filled with [[carbon monoxide]] and air as a sail to travel by wind for thousands of miles, dragging behind long tentacles that deliver a deadly venomous sting to fish.<ref name=Iosilevskii2009>{{cite journal|last1=Iosilevskii|first1=G.|last2=Weihs|first2=D.|title=Hydrodynamics of sailing of the Portuguese man-of-war ''Physalia'' physalis|journal=Journal of the Royal Society Interface|volume=6|issue=36|pages=613–626|year=2009|pmid=19091687|pmc=2696138|doi=10.1098/rsif.2008.0457}}</ref> This sailing ability, combined with a painful sting and a life cycle with seasonal blooms, results in periodic mass beach strandings and occasional human envenomations, making ''P. physalis'' the most infamous of the siphonophores.<ref name=Munro2019>{{cite journal | last1=Munro | first1=Catriona | last2=Vue | first2=Zer | last3=Behringer | first3=Richard R. | last4=Dunn | first4=Casey W. | date=October 2019 | title=Morphology and development of the Portuguese man of war, Physalia physalis | journal=Scientific Reports | publisher=Springer Science and Business Media LLC | volume=9 | issue=1 | page=15522 | issn=2045-2322 | doi=10.1038/s41598-019-51842-1 | pmid=31664071 | pmc=6820529 | bibcode=2019NatSR...915522M}} [[File:CC-BY icon.svg|50px]] Material and modified material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License] {{Webarchive|url=https://web.archive.org/web/20171016050101/https://creativecommons.org/licenses/by/4.0/ |date=2017-10-16 }}.</ref> Despite being a common occurrence, the origin of the man o' war or bluebottle before reaching the coastline is not well understood, and neither is the way it drifts at the surface of the ocean.<ref name=Lee2021 />

===Left- and right-handedness===
[[File:Physalia physalis EM1B0679 (40827501481).jpg|thumb|Looking down from above a man o' war, showing its sail. Sails can be left-handed or right-handed.]]
The Portuguese man o' war is asymmetrically shaped: the zooids hang down from either the right or left side of the midline of the pneumatophore or bladder. The pneumatophore can be oriented [[Chirality|towards the left or the right]]. This phenomenon may be an adaptation that prevents an entire population from being washed on shore to die. The "left-handed" animals sail to the right of the wind, while the "right-handed" animals sail to the left. The wind will always push the two types in opposite directions, so at most half the population will be pushed towards the coast.<ref name=Totton1956>Totton, A. and Mackie, G. (1960) "Studies on Physalia physalis", ''Discovery Reports'', '''30''': 301–40.</ref><ref name=Woodcock1944>Woodcock, A. H. (1944) "A theory of surface water motion deduced from the wind-induced motion of the Physalia", ''J. Marine Res.'', '''5''': 196–205.</ref> Regional populations can have substantial differences in float size and the number of tentacles used for hunting. The regional form previously known as ''P. utriculus'' has a bladder rarely exceeding {{convert|10|cm|sigfig=1}} in length and has one long hunting tentacle that is less than {{convert|3|m|sigfig=1}} long. In comparison, the typical man o' war has a float of around {{convert|15|to|30|cm|sigfig=2}}, and several hunting tentacles that can reach {{convert|30|m|sigfig=1}} in mature colonies when fully extended.<ref name=Munro2019/><ref name=Lee2021/> When combined with the trailing action of the tentacles, this left- or right-handedness makes the colony sail sideways relative to the wind, by about 45° in either direction.<ref name=Woodcock1956>{{cite journal|last=Woodcock|first=A.H.|title=Dimorphism in the Portuguese man-of-war|journal=Nature|volume=178|issue=4527|pages=253–255|year=1956|doi=10.1038/178253a0|bibcode=1956Natur.178..253W|s2cid=4297968|url=https://www.nature.com/articles/178253a0}}</ref><ref name=Iosilevskii2009/> Colony handedness has therefore been theorized to influence man o' war migration, with left-handed or right-handed colonies potentially being more likely to drift down particular respective sea routes.<ref name=Woodcock1956/> Handedness develops early in the colony's life, while it is still living below the surface of the sea.<ref name=Munro2019/>

===Mathematical modelling===
Since they have no propulsion system, the movement of the man o' war can be modelled mathematically by calculating the forces acting on it, or by [[Advection|advecting]] virtual particles in [[Ocean general circulation model|ocean]] and [[Atmospheric circulation|atmospheric circulation models]]. Earlier studies modelled the movement of the man o' war with [[Lagrangian particle tracking]] to explain major beaching events. In 2017, Ferrer and Pastor were able to estimate the region of origin of a significant beaching event on the southeastern [[Bay of Biscay]]. They ran a Lagrangian model backwards in time, using wind velocity and a wind [[drag coefficient]] as drivers of the man o' war motion. They found that the region of origin was the [[Sargasso Sea|North Atlantic subtropical gyre]].<ref name=Ferrer2017>{{cite journal|last1=Ferrer|first1=Luis|last2=Pastor|first2=Ane|title=The Portuguese man-of-war: gone with the wind|journal=Regional Studies in Marine Science|volume=14|issue=|pages=53–62|year=2017|bibcode=2017RSMS...14...53F|doi=10.1016/j.rsma.2017.05.004}}</ref> In 2015 Prieto et al. included both the effect of the [[ocean current|surface currents]] and wind to predict the initial colony position prior to major beaching events in the Mediterranean.<ref name=Prieto2015>{{cite journal|last1=Prieto|first1=L.|last2=MacÍas|first2=D.|last3=Peliz|first3=A.|last4=Ruiz|first4=J.|title=Portuguese Man-of-War (Physalia physalis) in the Mediterranean: A permanent invasion or a casual appearance?|journal=Scientific Reports|volume=5|issue=1|page=11545|year=2015|doi=10.1038/srep11545|pmid=26108978|pmc=4480229|bibcode=2015NatSR...511545P|s2cid=8456129}}</ref> This model assumed the man o' war was advected by the surface currents, with the effect of the wind being added with a much higher wind drag coefficient of 10%. Similarly, in 2020 Headlam et al. used beaching and offshore observations to identify a region of origin, using the joint effects of surface currents and wind drag, for the largest mass man o' war beaching on the Irish coastline in over 150 years.<ref name=Headlam2020>{{cite journal |doi = 10.1016/j.ecss.2020.107033|title = Insights on the origin and drift trajectories of Portuguese man of war (Physalia physalis) over the Celtic Sea shelf area|year = 2020|last1 = Headlam|first1 = Jasmine L.|last2 = Lyons|first2 = Kieran|last3 = Kenny|first3 = Jon|last4 = Lenihan|first4 = Eamonn S.|last5 = Quigley|first5 = Declan T.G.|last6 = Helps|first6 = William|last7 = Dugon|first7 = Michel M.|last8 = Doyle|first8 = Thomas K.|journal = Estuarine, Coastal and Shelf Science|volume = 246|page = 107033|bibcode = 2020ECSS..24607033H|s2cid = 224908448}}</ref><ref name=Lee2021/>  These earlier studies used numerical models in combination with simple assumptions to calculate the drift of this species, excluding complex drifting dynamics. In 2021, Lee ''et al.'' provide a [[Parametric equation|parameterisation]] for Lagrangian modelling of the bluebottle by considering the similarities between the bluebottle and a [[Forces on sails|sailboat]]. This allowed them to compute the hydrodynamic and aerodynamic forces acting on the bluebottle and use an equilibrium condition to create a generalised model for calculating the drifting speed and course of the bluebottle under any wind and ocean current conditions.<ref name=Lee2021/>