Like other Cnidarians, this species is radially symmetrical. They have distinct tissues, but no organs, and only one body opening. The tissues are the outer epidermis, the inner gastrodermis, and a middle layer of gelatinous mesoglea, which has a cartilege-like consistency. The medusa stage is most prominant, and no bottom-dwelling stage exists. The umbrella edge is divided into eight lobes, where sense organs such as light receptors and odor pits are located. The umbrella can be bell-shaped or hemispherical, and color can range from purple to brownish-red. Pelagia noctiluca has a frilled edge on the bell, with eight thin, stinging tentacles and four lobes hanging down from the mouth, called oral arms. The tentacles are very elastic. The name means "night light" in German for a reason. Very colorful, this jellyfish phosphoresces when disturbed and can leave a luminous mucous behind if handled. It is called the "mauve jelly" by the British. Also known as the oceanic jelly, this species is adapted to life in the open water. It is in the class Scyphozoa, the true jellyfish. The estimated lifespan of Pelagia noctiluca is two to six months, and death is usually caused by rough waters. (Grzimek 1972; Stachowitsch 1991;Calder 2000; Marr 1999)
Other Physical Features: ectothermic ; radial symmetry
The habitat is primarily pelagic, or in the open ocean. However, this species can survive almost anywhere ocean currents carry it, including benthic and temperate coastal habitats. (Calder 2000;Grzimek 1972)
Aquatic Biomes: benthic ; coastal
Found in the Mediterranean and the Atlantic Ocean, it lives mainly in the open ocean as well as in coastal waters. (Grzimek 1972)
Biogeographic Regions: atlantic ocean (Native )
Carnivorous like other Cnidarians, this species preys mainly on zooplankton, small fish, crustaceans, other jellyfish, and eggs. Pelagia noctiluca captures its prey with tentacles armed with cnidocytes, each of which contains a nematocyst. Nematocysts have barbed filaments to trap their prey and toxins to stun them. They can even pierce the shell of a crab with their barbs. Food is digested intracellularly as well as extracellularly, in a gut cavity, enabling them to eat multicellular animals. (Raven and Johnson 1999; Banister and Campbell 1985)
Pelagia noctiluca are beautiful, especially when they phosphoresce. The chemical reactions causing their luminescence are currently of great interest to researchers. Other jellyfish are used for medical and therapeutic purposes, and Pelagia noctiluca might soon be helpful for humans. One possible use of their fluorescent protein is as a genetic marker to detect protein movement or gene expression in research in developmental, environmental and medical biology. (Manning 1997)
-Pelagia noctiluca- is among the jellyfish that scare tourists away from beaches, especially in the Mediterranean. Italian beaches were overrun by large groups of them in the summer of 1999. The sting of -Pelagia noctiluca- is venomous to humans, but normally only causes a whip-like scar across the body. In rare cases of allergic reactions, life-threatening conditions like anaphylactic shock can occur. Fishermen are also affected by jellyfish, including -Pelagia noctiluca- . There have been reports from France of jellyfish tearing holes in fishing nets. (Marr 1999;Calder 2000)
-Pelagia noctiluca- is not in danger of extinction at the present time. They are multiplying in number in the Mediterranean, but are expected to return to normal levels in the next few years. (Marr 1999)
US Federal List: no special status
The adults, which have separate sexes, reproduce sexually by releasing gametes from gonads located near the center of the body. The ova and sperm are released through the mouth of the jellyfish, and fertilize externally. Each fertilized egg forms a planulae, an undifferentiated mass of cells that swims with external cilia. Planula may be widely dispersed by oceanic currents. Unlike other species which have a bottom-dwelling polyp stage, Pelagia noctiluca's planulae develop directly into ephyrae, young medusae. The ephyrae quickly grows into an adult medusa, completing the life cycle. (Banister and Campbell 1985; Stachowitsch 1991;Calder 2000)
Parental Investment: no parental involvement
Pelagia noctiluca és una medusa de la classe dels escifozous, de distribució atlàntica i mediterrània, que ocupa preferentment hàbitats pelàgics però que pot formar eixams que arriben a la línia de costa, impedint el bany atesa la naturalesa extremadament urticant dels seus cnidocits.
A Wikimedia Commons hi ha contingut multimèdia relatiu a: Pelagia noctilucaDie Leuchtqualle (Pelagia noctiluca), auch Feuerqualle genannt, ist eine Schirmqualle aus der Familie der Pelagiidae und gehört zu den wenigen europäischen Quallen, deren Nesselkapseln die menschliche Haut durchdringen können. Der Gattungsname Pelagia ist von griechisch pelagós ‚Meer‘ abgeleitet (es gibt auch eine Heilige gleichen Namens). Ihren Artnamen noctiluca – „die Nachtleuchtende“ – verdankt sie ihrem schwachen, nächtlichen Leuchten, das bei Erschütterung der Qualle sichtbar wird (Biolumineszenz).
Der Schirm ist hochgewölbt und hat die Form einer Halbkugel oder Glocke. Er kann einen Durchmesser von 10–12 cm erreichen. Die Farbe dieser Meduse reicht von einem blassen Pink bis hin zu malvenfarben und bräunlich, die Schirmoberfläche ist mit pink oder mauve-farbenen, nesselzellenbewehrten Warzen überzogen. Der Schirm trägt unterseitig sechzehn marginale Lappen und acht marginale Sinnesorgane.[1] Rund um die Mundöffnung befinden sich vier, außen gekrauste Mundtentakel, am Schirmrand acht fadenförmige, bis einen Meter lange Fangtentakel. Die Fangtentakel sind mit zahllosen Nematozysten besetzt, die ihrerseits mit Proteintoxiden mit einer molaren Masse von 50–150 kDa gefüllt sind.[2]
Die Leuchtqualle lebt kosmopolitisch in wärmeren Meeren (zum Beispiel dem Mittelmeer, dem Roten Meer und im Golf von Mexiko) und tritt meist in Schwärmen auf.[3][2] Dabei können die Wanderpopulationen kilometerlang sein und in einer Tiefe von bis zu 20 m auftreten.[4] Pelagia noctiluca macht kein sessiles Polypenstadium durch, die adulten Tiere entlassen im Herbst voll entwickelte Jungmedusen. Die übliche Beute dieser Qualle sind freischwimmende Seescheiden, kleinere Quallen[1] und Zooplankton.[3]
Pelagia noctiluca gehört der Klasse der Schirmquallen (Scyphozoa) aus dem Stamm der Nesseltiere (Cnidaria) an, ihre Familie (Pelagiidae) umfasst die Arten Pelagia flaveola, P. noctiluca und P. panopyra. Ein Synonym für P. noctiluca ist Pelagia perla (Slabber, 1781).[3]
Die mikroskopisch kleinen Harpunen der Nesselzellen durchdringen die menschliche Haut. Das Nesselgift löst eine sofortige Kontakturtikaria aus, die schmerzhaft, aber nicht lebensgefährlich ist. Folgen sind eine errötende Haut der jeweilig betroffenen Stelle, sowie ein starker Juckreiz. In wenigen Fällen kann es jedoch zur Systematisierung (Übelkeit, Erbrechen und Kopfschmerzen) kommen. Erste-Hilfe-Maßnahmen umfassen das sofortige Entfernen anhaftender Tentakel und die Neutralisierung des Giftes mit einer Magnesiumsulfatlösung.[2]
Massenauftreten von Leuchtquallen bedrohen Aquakulturen. Es gab Fälle, in denen bis zu 100.000 Lachse umgebracht wurden.[5] In den letzten Jahren häufen sich auch Meldungen über ungewöhnliche Massenvorkommen im Mittelmeer, die dann zu Strandsperrungen führen. Für die jeweilige örtliche Tourismusindustrie sind derlei Vorfälle problematisch, da die Badegäste fernbleiben.[6]
Die Leuchtqualle kann als invasive Art bezeichnet werden, da die eigentliche Hochseequalle periodisch in Küstengewässer getrieben wird, wo sie zu Schäden führt.[7]
Die Leuchtqualle (Pelagia noctiluca), auch Feuerqualle genannt, ist eine Schirmqualle aus der Familie der Pelagiidae und gehört zu den wenigen europäischen Quallen, deren Nesselkapseln die menschliche Haut durchdringen können. Der Gattungsname Pelagia ist von griechisch pelagós ‚Meer‘ abgeleitet (es gibt auch eine Heilige gleichen Namens). Ihren Artnamen noctiluca – „die Nachtleuchtende“ – verdankt sie ihrem schwachen, nächtlichen Leuchten, das bei Erschütterung der Qualle sichtbar wird (Biolumineszenz).
Pelagia noctiluca is a jellyfish in the family Pelagiidae and the only currently recognized species in the genus Pelagia.[1] It is typically known in English as the mauve stinger,[2][3] but other common names are purple-striped jelly (causing potential confusion with Chrysaora colorata),[4] purple stinger, purple people eater,[5] purple jellyfish, luminous jellyfish and night-light jellyfish.[6] In Greek, pelagia means "(she) of the sea", from pelagos "sea, open sea";[7] in Latin noctiluca is the combining form of nox, "night"", and lux, "light";[8] thus, Pelagia noctiluca can be described as a marine organism with the ability to glow in the dark (bioluminescence). It is found worldwide in tropical and warm temperate seas,[2][3] although it is suspected that records outside the North Atlantic region, which includes the Mediterranean and Gulf of Mexico,[9] represent closely related but currently unrecognized species.[10]
A fairly small and variably coloured species, both its tentacles and (unusual among jellyfish) bell are covered in stinging cells.[2][11] Stinging incidents are common, painful and the symptoms may continue for a considerable time after the encounter, but they are generally not dangerous.[2] When large numbers of this oceanic species are washed ashore, the local economy can be affected because tourists avoid the beaches and fishers are stung while trying to retrieve their nets, which can be clogged by the jellyfish.[2][9] Additionally, swarms of Pelagia noctiluca have been recorded wiping out entire fish farms.[12][13] Because of this, it has become one of the most studied jellyfish species.[14]
This jellyfish is best known from the North Atlantic region, ranging from 4th parallel north (just north of Equator) to the North Sea and Atlantic Canada, including the Mediterranean and Gulf of Mexico.[9][15]
There are reports from most other tropical or warm temperate seas around the world, including both the Pacific and Indian Oceans, with its apparent southern limit being 42nd parallel south.[2][3] Some of the locations are California (rare),[16] Hawaii (rare),[3] and all around Australia (common).[11] However, it is suspected that Pelagia noctiluca—as currently defined—is a species complex with records outside the North Atlantic region involving other closely related species that presently are unrecognized or undescribed.[10] Even North Atlantic and South Atlantic populations show significant genetic differences.[17] A comprehensive taxonomic review is necessary to resolve the situation.[18] In 2014, a second species in the genus Pelagia was described from the Mediterranean, but two years later it was moved to its own genus as Mawia benovici.[19]
The swimming ability of Pelagia noctiluca is limited and as a result large swarms (also known as blooms) of this oceanic species are occasionally carried by the wind or current to inshore areas, sometimes ending up stranded on beaches.[2][9] This also means that the species sometimes appears in waters outside its normal temperature preference, with records as far north as the Shetland Islands and the Norwegian deep.[2] It generally occurs at water temperatures between 10 and 27 °C (50–81 °F), but below 11 °C (52 °F) it stops pulsating.[3] It mostly ranges from the surface to a depth of 150 m (490 ft), but has been recorded to 1,400 m (4,600 ft).[2] Pelagia noctiluca partakes in the diel vertical migration, occurring near the surface at night and deeper during the day.[20]
Local populations fluctuate greatly and the species may go virtually unrecorded in a region for years, only to suddenly reappear in huge swarms.[9][21][22] On occasion, a swarm may cover tens of square kilometers,[23] include millions of Pelagia noctiluca,[24] and reach densities of more than 500 individuals per m3 (14 per ft3).[20]
Pelagia noctiluca are fairly small jellyfish with adults having a bell diameter of 3–12 cm (1.2–4.7 in).[2] Their colour is variable, ranging from mauve, purple, pink, light brown to yellow.[2][16] The body is radially symmetrical. There is only one body cavity known as the gastrovascular cavity. This is a primitive gut or digestive cavity with only one opening that is used for ingestion and excretion; there are four long oral arms with crenulated margins that are the primary feeding surface. Each P. noctiluca medusa has eight long tentacles that emerge from the umbrella margin. Being radially symmetrical it has no head and thus no centralized nervous system. The nervous system present is primitive, consisting of a simple net composed of naked and largely non-polar neurons. In addition P. noctiluca also lacks a gaseous exchange, excretory and circulatory system. However cnidaria have evolved cnidae, cells which serve for a variety of functions that include prey capture, defense, locomotion and attachment. When fully formed cnidae are called cnidocytes. When stimulated the cnidae secrete nematocyst toxins that are biological poisons.
These organisms have a well-developed manubrium, a proboscis-like structure bearing the mouth and four long oral arms. Also the mesoglea, or jelly, is relatively thickened and well developed in this species. Sense organs, known as rhopalia in the scyphomedusae, are located around the umbrella margin in notches and alternate between tentacles. Cnidae are present in the epidermis and gastrodermis of the umbrella, as well as on the tentacles.
Pelagia noctiluca has eight marginal tentacles alternating with eight marginal sense organs. Four gonads arise as elongated endodermal proliferations, developing into ribbon-like folds in the interradial sectors of the stomach wall slightly distal to the rows of gastric filaments. Male and female gonads vary only slightly and the main difference is the thickness of the follicle.
Pelagia noctiluca are bioluminescent, i.e. have an ability to produce a low light that is visible to humans during the night. Light is emitted in the form of flashes when the medusa is stimulated by turbulence created by waves or by a ship's motion. This flashing is only of relatively short duration and gradually fades. A very early description of bioluminescence was provided by Pliny the Elder in Historia Naturalis (77 AD), using the name "pulmo marinus", and now considered to refer to P. noctiluca.[25][26]
Pelagia noctiluca is adapted to a pelagic, open-sea mode of life. Whereas most jellyfish, including the other species in the family Pelagiidae, have a life cycle with both the free-swimming stages (planula, ephyra and medusa) and a bottom-living polyp stage, P. noctiluca has adapted in such a way that the polyp stage is absent.[27] P. noctiluca reproduces sexually with the male and female spawning respectively sperm and eggs into the sea during daylight hours. After 3 days, the fertilized egg develops into a planula; at this stage movement is only done by ciliary action. After a week, planulae develop into tiny ephyrae and a month later they develop into (male or female) medusae.[3] There is little or no ephyra growth at temperatures below 10 °C (50 °F),[21] and fewer survive below 8 °C (46 °F).[28] The bottom-living polyp stage of most other jellyfish species is in between the planula and ephyra stages.[27] Initially, the medusa of P. noctiluca only has a bell diameter of about 1 cm (0.4 in). Some already reach maturity at 3.5 cm (1.4 in) in bell diameter and at 6 cm (2.4 in) all are mature.[21] In the Mediterranean Sea, P. noctiluca appear to mostly spawn between the late summer and early winter, but also at lower levels in the spring to early summer.[9][21] P. noctiluca rely on favorable trophic conditions to spawn, so when their criteria is not met, the medusae will stop reproducing immediately and lose weight when presented with an inadequate amount of food.[29] Large swarms of adults at the ocean surface in certain times of the year possibly are spawning aggregations.[9] This jellyfish typically lives for about 9 months.[21]
Pelagia noctiluca are opportunistic and have been recorded feeding on a wide range of small organisms like planktonic crustaceans (cladocerans, copepods, ostracods and crustacean larvae), mollusk larvae, larvaceans, hydromedusae, siphonophorans, arrow worms, fish eggs and fish larvae,[3][9][20] as well as detritus suspended in the open water and microscopic phytoplankton.[30] The phytoplankton can be consumed either directly or indirectly by eating herbivorous crustaceans with stomachs filled with it. The ability to eat phytoplankton is—as far as known—highly unusual among cnidarians.[30] P. noctiluca will eat small warty comb jellies (Mnemiopsis leidyi), potentially helping to control this invasive species.[31] Cannibalism where adults consume young of their own species is also common in P. noctiluca.[20] The stomach contents of P. noctiluca also vary throughout the seasons. Copepods tend to be their largest food source all year round, but fish eggs and pteropods are a close second. During the spring months, P. noctiluca mainly prey on copepods and fish eggs, while pteropods are preyed on more during December and May. The variability in this species' diet suggests that they are generalists, and do not have strong prey selectivity.[32]
Feeding reactions were studied by Bozler (1926), where a piece of food was given to the marginal tentacle, the tentacle contracted quickly. There was a slow contraction of the coronal muscle which brought the tentacle nearer to the mouth. The food was grasped by the lip of one of the oral arm and transported slowly along until it reached the stomach. They were found to feed on the salp Thalia democratica; however, they are found mainly to feed by taking food particle by the amoeboid process of the endoderm cells, thus being suspension feeders.
Pelagia noctiluca is considered the most important stinging jellyfish in the Mediterranean Sea.[2][9] Both its tentacles and—unusual among jellyfish—the bell are covered in cnidocytes (stinging cells), and even recently dead, stranded individuals can sting.[2] P. noctiluca contains four different types of nematocysts, but two are important for stinging, O-isorhiza and eurytele.[33] The sting causes pain that typically lasts 1–2 weeks, local redness, swelling and a rash, but it is generally not dangerous and there are no known fatalities.[2][34] On occasion, symptoms may be more general and include dizziness, vomiting and diarrhea. Sudden recurrent skin eruptions may occur years later. Rarely, the sting can cause a serious allergic reaction and leave scars or hyperpigmented marks on the skin that can remain for years after the encounter.[2] If stung by P. noctiluca there can be cross-reactivity (an allergic reaction) if later stung by Portuguese man o' war (Physalia physalis) or sea nettles (Chrysaora).[2][34] There is one known case where a sting by P. noctiluca caused Guillain–Barré syndrome, but all symptoms disappeared within 6 months.[35] Peculiarly, there is a record of a seven-arm octopus "borrowing" the stinging capability of a P. noctiluca. The open-sea octopus grabbed and positioned the jellyfish in such a way that it provided a defense.[36] The sting of P. noctiluca can possibly be relieved with the use of Hydroxyacetophenone and Symsitive® since they are nematocyst inhibitor compounds, meaning they inhibit the discharge of cnidocysts.[33]
{{cite web}}
: CS1 maint: DOI inactive as of April 2023 (link) CS1 maint: url-status (link) Pelagia noctiluca is a jellyfish in the family Pelagiidae and the only currently recognized species in the genus Pelagia. It is typically known in English as the mauve stinger, but other common names are purple-striped jelly (causing potential confusion with Chrysaora colorata), purple stinger, purple people eater, purple jellyfish, luminous jellyfish and night-light jellyfish. In Greek, pelagia means "(she) of the sea", from pelagos "sea, open sea"; in Latin noctiluca is the combining form of nox, "night"", and lux, "light"; thus, Pelagia noctiluca can be described as a marine organism with the ability to glow in the dark (bioluminescence). It is found worldwide in tropical and warm temperate seas, although it is suspected that records outside the North Atlantic region, which includes the Mediterranean and Gulf of Mexico, represent closely related but currently unrecognized species.
A fairly small and variably coloured species, both its tentacles and (unusual among jellyfish) bell are covered in stinging cells. Stinging incidents are common, painful and the symptoms may continue for a considerable time after the encounter, but they are generally not dangerous. When large numbers of this oceanic species are washed ashore, the local economy can be affected because tourists avoid the beaches and fishers are stung while trying to retrieve their nets, which can be clogged by the jellyfish. Additionally, swarms of Pelagia noctiluca have been recorded wiping out entire fish farms. Because of this, it has become one of the most studied jellyfish species.
Pelagia noctiluca, el acalefo luminiscente, medusa luminescente o clavel,[1] es una especie de medusa de la clase de los escifozoos, de distribución atlántica y mediterránea, que ocupa preferentemente hábitats pelágicos pero puede formar enjambres que llegan a la línea de costa, impidiendo el baño dada la naturaleza extremadamente urticante de sus cnidocitos.
Su implicación en la aparición de plagas de medusas tiene varias posibles causas, cuya ponderación en relevancia varía según el autor:
Su coloración es violeta rosácea brillante, y presenta la umbrela abultada, con 16 lóbulos periféricos, 8 órganos sensoriales carentes de ojos, 8 tentáculos y un espacio gástrico con 16 canales radiales.[2]
Pelagia noctiluca, el acalefo luminiscente, medusa luminescente o clavel, es una especie de medusa de la clase de los escifozoos, de distribución atlántica y mediterránea, que ocupa preferentemente hábitats pelágicos pero puede formar enjambres que llegan a la línea de costa, impidiendo el baño dada la naturaleza extremadamente urticante de sus cnidocitos.
Su implicación en la aparición de plagas de medusas tiene varias posibles causas, cuya ponderación en relevancia varía según el autor:
El incremento en nutrientes en mares y océanos, por vertidos de fertilizantes y de aguas negras de los núcleos urbanos, lo que acentúa la disponibilidad de nitrógeno y fósforo en los mares. Una menor depredación por la disminución en el número de predadores naturales, como la tortuga boba o el atún rojo. El incremento de la temperatura de los mares, que aceleran su ciclo vitalMerikell (Pelagia nocticula) on karikloomade klassi kuuluv mereeluline ainuõõsne.
Merikellade keha on radiaalselt sümmeetriline. Neil on 8 m pikad kombitsad[viide?]. Närvisüsteem on primitiivne. Liikumine on piiratud ainult vertikaalselt. Liikumine on põhjustatud karika pulseerimisest. Nende värvus on roosa ja kahvatulilla, mõnikord ka kuldkollane.
Neil on võime pimedas helendada. Nad vilguvad ainult suhteliselt lühikese kestusega ja valgus järk-järgult kaob.
Merikella levilaks on soojaveelised ja parasvöötme veed, sealhulgas Vahemeri, Punane meri ja Atlandi ookean. Teda on leitud ka Vaiksest ookeanist.
Loistomeduusa (Pelagia noctiluca) on ihmisellekin vaarallinen vaaleanpunainen polttiaiseläin (Cnidaria).
Loistomeduusan kello on halkaisijaltaan noin kymmensenttinen. Sen lonkerot voivat kasvaa kymmenen metriä pitkiksi.[2] Sen vaaleanpunertava kello hohtaa valoa, jos meduusaa häiritään, ja se voi myös paeta ja jättää jälkeensä hohtavaa limaa.[3]
Loistomeduusaa tavataan Välimerellä, Punaisellamerellä ja Atlantin lämpimissä osissa.[2] Sitä on tavattu myös Britteinsaarten vesillä, joissa se on kuitenkin harvinainen.[4]
Loistomeduusat elävät avomerellä suurissa parvissa, jopa 45 kilometrin mittaisia parvia on havaittu. Ne pystyvät liikkumaan supistelemalla kelloaan, tai säätelemällä sulfidi-ionien määrää kehossaan[5], mikä vaikuttaa niiden kellumissyvyyteen. Enimmäkseen meduusat kuitenkin ajelehtivat merivirtojen mukana.[3]
Loistomeduusat syövät enimmäkseen eläinplanktonia, pieniä kaloja, äyriäisiä, toisia meduusoita ja muiden lajien mätiä. Lonkeroissa on pieniä väkäsiä, joilla meduusa tarttuu saaliiseen, ja myrkkyaineita, jotka tainnuttavat uhrin. Loistomeduusa voi lävistää jopa taskuravun suojakuoren myrkkyväkäsillään.[3]
Loistomeduusa (Pelagia noctiluca) on ihmisellekin vaarallinen vaaleanpunainen polttiaiseläin (Cnidaria).
Pelagia noctiluca, aussi connue sous le nom de méduse pélagique, pélagie ou piqueur-mauve, est une espèce de méduses de l'embranchement des cnidaires, de la classe des scyphozoaires, et de la famille des Pelagiidae.
Cette espèce exclusivement pélagique forme de larges bancs de plusieurs centaines, voire plusieurs milliers de spécimens, qui se déplacent au gré des courants.
L'espèce est décrite sous le nom de Medusa noctiluca par le naturaliste suédois Pehr Forsskål lors de sa traversée de la Méditerranée en 1775[1]. En grec, l'adjectif πελάγια (pelágia) signifie « de la haute mer » ; le latin nocti(s) veut dire « de la nuit » et le suffixe luca est dérivé du latin lux, lucis, la « lumière ». Ainsi Pelagia noctiluca peut être compris comme la dénomination d'un organisme marin ayant la faculté de briller dans le noir. Cette propriété est due à un mucus lumineux produit par l'enveloppe de l'animal lorsque celui-ci est dérangé par les vagues.
Pelagia noctiluca est une méduse scyphozoaire phototrope négative qui est, contrairement à la plupart des scyphoméduses, exclusivement pélagique[2].
Ce cnidaire possède une ombrelle crénelée (seize plis marginaux, de forme rectangulaire avec les coins arrondis et des entailles médianes peu profondes), arrondie ou aplatie suivant le degré de contraction, de 3 à 12 cm chez les adultes[3]. La marge de l'ombrelle présente huit rhopalies (constitués uniquement d’un statocyste et d’un bulbe sensoriel, mais sans ocelles) alternant avec huit longs tentacules blanchâtres creux, pouvant atteindre 40 centimètres. Le manubrium attaché à la sous-ombrelle est prolongé par quatre longs bras buccaux, de couleur rosâtre, festonnés pouvant atteindre 15 centimètres de longueur. L'ensemble du corps est recouvert de cnidocytes (cellules à nématocystes urticants) qui peuvent provoquer de vives douleurs en cas de contact avec la peau. Un seul tentacule peut porter des centaines jusqu’à des milliers de cnidocytes dans son ectoderme[4]. L'ombrelle et les bras buccaux sont parsemés de très nombreuses verrues mauves qui contiennent ces cnidocytes. Les bras buccaux capturent et paralysent les proies faisant partie du zooplancton (90 % de crustacés — cladocères et copépode —, cténaires, petites méduses, thaliacés voire petits poissons)[5] et les ramènent, grâce à un mucus gluant, vers le manubrium. La digestion est extracellulaire et a lieu au sein de le cavité sous-ombrellaire. Les restes non digérés sont rejetés par la bouche[6]. Le régime alimentaire semble opportuniste, la prédation de cette espèce étant plutôt gouvernée par la disponibilité de la nourriture que par la préférence alimentaire[7].
Possédant quatre pigments, elle présente une coloration rougeâtre variée, allant de l'orange au violet en passant par le rose, et un dichromatisme sexuel : les femelles sont plutôt marron et les mâles violets[8]. Son ectoderme (chapeau) est transparent et urticant et laisse entrevoir sa mésoglée, son endoderme et ses gonades. Elle brille grâce à un mucus sécrété par son ectoderme lorsque la méduse est perturbée ou heurtée par les vagues.
Contrairement aux autres espèces de sa famille, cette Pélagie semelpare, à gonochorisme stable, est caractérisée par un cycle de développement hypogénétique, holoplanctonique et direct[9] : à l'automne, les méduses mâles libèrent par leur cavité orale des spermatozoïdes directement dans l'eau de mer. Ces cellules reproductrices pénètrent dans la cavité orale des méduses femelles qui y ont également libéré leurs ovocytes. Après cette fertilisation externe, la fécondation interne a lieu dans la cavité gastrique des méduses femelles qui libèrent par leur cavité orale un nuage jaune d'œufs (jusqu'à 19 000 œufs en laboratoire[10]) en pleine mer. Ces œufs éclosent au bout de deux jours, donnant naissance à une petite larve de type planula. En 44 heures, cette larve se transforme progressivement en une larve ephyra qui évolue progressivement pour donner une jeune méduse. Elle passe donc directement au stade de méduse adulte, sans stade scyphistome (petit polype).
Cette Pélagie peut survivre plusieurs semaines sans nourriture et supporter des variations de température de l'eau allant de 13 à 25 degrés[10].
Cette espèce de méduse pélagique est largement présente dans toutes les eaux chaudes et tempérées, comme la mer Méditerranée, la mer Rouge, ou l'océan Atlantique. Il est plausible que son aire de répartition puisse se déplacer vers le nord avec le réchauffement climatique. C'est un phénomène observé depuis quelques décennies pour diverses espèces de poissons, mais aussi de plancton. C'est la méduse méditerranéenne type, qui abonde sur le littoral certains étés, notamment celui de Marseille à l'Italie, apportée par le courant liguro-provençal qui longe les côtes du golfe de Gênes aux Baléares[11].
C'est une méduse urticante dont la piqûre provoque pour les baigneurs une sensation de brûlure, des démangeaisons, des lésions cutanées relativement importantes, voire des allergies pouvant occasionner des chocs anaphylactiques. Cette espèce n’est pas létale, contrairement à d’autres retrouvées en Australie, mais des accidents mortels ont été signalés, de manière exceptionnelle lorsque ces chocs allergiques ne sont pas traités assez vite ou que de nombreuses piqûres peuvent induire un affolement du baigneur où il n'a plus pied et une noyade[12].
Des colonies de cette « ortie de mer » envahissent ou s’échouent sur des plages des côtes méditerranéennes où elle est devenue depuis les années 2000 la terreur des baigneurs[13]. Cet impact touristique incite des gérants de plages privées et les communes de la Côte d'azur à investir dans des filets de protection[10] ou des robots découpeurs de méduses. Ces équipements ont cependant comme conséquence possible de former une « soupe urticante ». Les méduses « vont s’écraser contre les mailles, d’autres animaux aussi, au demeurant. Stressées, elles vont secréter un mucus urticant et leurs tentacules vont se briser tout en restant venimeux »[14]. De plus, la prise de ces animaux dans des filets ou leur hachage induit la production de spermatozoïdes et d'ovules, ce qui favorise la pullulation de méduses[15]. L’observatoire océanologique de Villefranche-sur-Mer a lancé en 2012 un « bulletin météo des méduses » mais les collectivités locales, soucieuses de gérer l'impact touristique, ont supprimé leurs financements[14].
Les cycles à Pelagia débutaient environ tous les douze ans (par exemple, trois ans de présence, puis neuf ans tranquilles) mais ces cycles se sont accélérés depuis 1999 et elle est désormais présente chaque année[16]. Ce type de pullulation est plutôt habituellement observé en été. La prolifération de cette espèce, favorisée par la température élevée de l'eau et le nombre restreint de prédateurs, explique qu'elle peut envahir les ports et tuer la faune piscicole. Ainsi en Irlande du Nord, mi-novembre 2007 une pullulation qui semble avoir concerné une surface de 26 km2 environ, et 10 mètres de profondeur s'est déplacée vers une pisciculture, y tuant plus de 100 000 poissons (1 million £ de dégâts) [17].
Ces méduses peuvent également avoir un impact sur l’activité industrielle, notamment en bouchant les canalisations des centrales électriques et de dessalage[18].
Une marée de Pelagia noctiluca en Espagne.
Pelagia noctiluca, aussi connue sous le nom de méduse pélagique, pélagie ou piqueur-mauve, est une espèce de méduses de l'embranchement des cnidaires, de la classe des scyphozoaires, et de la famille des Pelagiidae.
Cette espèce exclusivement pélagique forme de larges bancs de plusieurs centaines, voire plusieurs milliers de spécimens, qui se déplacent au gré des courants.
Morska mjesečina (Pelagia noctiluca), meduza iz porodice Pelagiidae. Na latinskom Pelagia potječe od grč. pélagos: otvoreno more, dok noctiluca dolazi od lat. nox: noć i lat. lux: svjetlo, pa se Pelagia noctiluca može opisati kao morski organizam koji ima sposobnost svijetliti u tami.
Ova vrsta meduze koja nosi mnogo drugih pučkih naziva (npr. pučinska mjesečina) naširoko je distribuirana u svim toplim i umjereno toplim vodama svjetskih oceana uključujući Sredozemno more, Crveno more i Atlantski ocean. Može se pronaći i u Tihom oceanu, a viđena je u toplim vodama nedaleko od Havaja, južne Kalifornije i Meksika, ali i ostalim pacifičkim lokacijama. To je tipična odobalna, pučinska vrsta, premda ponekad može biti nanesena blizu obale, a može biti i naplavljena na plažama u velikom broju. Boja joj se razlikuje širom svijeta, a osim ružičaste ili ružičasto-ljubičaste, ponekad je u nijansama zlatnožute do brončane.
U dotad neviđenu događaju 21. studenoga 2007. godine jato morske mjesečine površine 26 km2 istrijebilo je 100.000 lososa u ribljem uzgajalištu u Sjevernoj Irskoj, uzrokovavši štetu od oko 1 milijun GBP.[2]
Morska mjesečina (Pelagia noctiluca), meduza iz porodice Pelagiidae. Na latinskom Pelagia potječe od grč. pélagos: otvoreno more, dok noctiluca dolazi od lat. nox: noć i lat. lux: svjetlo, pa se Pelagia noctiluca može opisati kao morski organizam koji ima sposobnost svijetliti u tami.
Ova vrsta meduze koja nosi mnogo drugih pučkih naziva (npr. pučinska mjesečina) naširoko je distribuirana u svim toplim i umjereno toplim vodama svjetskih oceana uključujući Sredozemno more, Crveno more i Atlantski ocean. Može se pronaći i u Tihom oceanu, a viđena je u toplim vodama nedaleko od Havaja, južne Kalifornije i Meksika, ali i ostalim pacifičkim lokacijama. To je tipična odobalna, pučinska vrsta, premda ponekad može biti nanesena blizu obale, a može biti i naplavljena na plažama u velikom broju. Boja joj se razlikuje širom svijeta, a osim ružičaste ili ružičasto-ljubičaste, ponekad je u nijansama zlatnožute do brončane.
U dotad neviđenu događaju 21. studenoga 2007. godine jato morske mjesečine površine 26 km2 istrijebilo je 100.000 lososa u ribljem uzgajalištu u Sjevernoj Irskoj, uzrokovavši štetu od oko 1 milijun GBP.
La medusa luminosa (Pelagia noctiluca), è una medusa della famiglia Pelagiidae.
È comune nel Mar Mediterraneo e nell'Oceano Atlantico orientale fino al Mare del Nord; è stata citata nelle cronache (nel 1992[1][2], 2003[1][2] e 2005[3]) per la sua abbondanza nei nostri mari in alcuni periodi e per le dolorose irritazioni che provoca se sfiorata.
È una specie pelagica, ma nel periodo autunnale e primaverile si avvicina alla costa.
Ombrello marrone-rosato o rosa-violetta di circa 10 centimetri di diametro, traslucido, composto da 16 lobi da cui partono 8 lunghi tentacoli retrattili, molto urticanti e semi-trasparenti, che partono dai bordi e si possono estendere fino a 2 metri. Le braccia orali, dello stesso colore dell'ombrello, sono lunghe fino a circa 30 centimetri.
L'epiteto specifico noctiluca deriva dall'iridescenza, di colore verde, di cui è dotata.
Si nutre di plancton e di piccoli pesci che cattura tramite i tentacoli dotati di urticanti nematocisti.
La P. noctiluca è una delle meduse che non attraversano lo stadio polipoide durante la maturazione. Gli adulti sono a sessi separati: la femmina depone le uova nel mare, che vengono fecondate dagli spermatozoi dei maschi. Dallo zigote nasce la planula, una larva dotata di ciglia per il movimento e che si disperde a livello planctonico. Non attraversa però lo stadio di scifistoma, ancorandosi al terreno, ma si divide direttamente in efira, una giovane medusa che poi crescerà a formare la medusa adulta.
La medusa luminosa (Pelagia noctiluca), è una medusa della famiglia Pelagiidae.
De parelkwal of lichtende kwal (Pelagia noctiluca) behoort tot de familie Pelagiidae.
In het Grieks betekent Pelagia “van de zee”, nocti “nacht” en luca “licht”. De kwal is in staat op te lichten in het donker.
De kwal met een diameter van tien centimeter heeft 8 tentakels bedekt met netelcellen, en nog 8 lange neteldraden die een lengte tot 3 meter kunnen bereiken. Deze tentakels kunnen erg ver worden uitgestrekt en samengetrokken. Het halfronde scherm verloopt van lichtpaars tot donkerrood. Bij bedreiging neemt deze kwal een 's nachts goed zichtbare, roodpaars oplichtende kleur aan.
Als de larve (planula) uit het bevruchte ei komt, volgt er een poliepstadium. De larve doorloopt een ontwikkeling tot babykwal (ephydra). Deze kwal hecht zich niet op een oppervlak en kan zodoende in zee leven. Deze kwallen kunnen een gevaar vormen voor badgasten, als ze door de getijden op het strand worden geworpen. Als mensen door de met netelcellen bezette filamenten worden gestoken, kan dit leiden tot een anafylactische shock.
Ze kunnen voor een echte plaag zorgen. De oorzaak van zulke plagen is nog onbekend. Men vermoedt een gebrek aan natuurlijke vijanden zoals tonijn, zwaardvis, trekkervis en de lederschildpad. Andere oorzaken kunnen zijn: gebrek aan neerslag, waardoor kustwater minder zoet en warmer wordt zodat de natuurlijke barrière doorbroken wordt, dan wel de aanwezigheid van grote hoeveelheden zoöplankton lang de kust.
Deze soort komt voornamelijk voor in de open warme en zoutere wateren van de Rode Zee, Atlantische oceaan en Middellandse Zee. Ze worden echter ook weleens massaal aan de kusten gesignaleerd
Bij aanraking van een parelkwal kan een ernstige pijn ontstaan. Andere symptomen zijn langdurige jeuk, het rood worden en opzwellen van de huid, duizeligheid, misselijkheid en braken. Na een steek kan je best de wonden afspoelen met zout water en daarna koelen met een ijscompres.
De rv Pelagia van het NIOZ is vernoemd naar deze kwal.
De parelkwal of lichtende kwal (Pelagia noctiluca) behoort tot de familie Pelagiidae.
In het Grieks betekent Pelagia “van de zee”, nocti “nacht” en luca “licht”. De kwal is in staat op te lichten in het donker.
Meduza świecąca, pelagia świecąca (Pelagia noctiluca) – gatunek krążkopława z rodzaju Pelagia zaliczanego do rodziny Pelagiidae.
Kolorystyka meduz z tego gatunku waha się na całym świecie, oprócz różowego i fiołkoworóżowego koloru, spotyka się osobniki w odcieniach żółtozłotych. Ciało osiąga średnicę do 7 cm. Ma 8 długich czułków zaopatrzonych w komórki parzydełkowe. Ich dotknięcie powoduje bolesne oparzenia.
Pokolenie polipa u tego gatunku jest całkowicie zredukowane[2].
W języku greckim Pelagia oznacza „z oceanu”, Nocti – „nocą” i Luca – „światło”, zatem Pelagia noctiluca można opisać jako morski organizm ze zdolnością do świecenia w ciemności.
Gatunek ten jest powszechnie znany w Europie, pod wieloma różnymi nazwami. Meduza świecąca jest szeroko rozpowszechniona we wszystkich ciepłych i umiarkowanych wodach oceanów na świecie, łącznie z Morzem Śródziemnym, Morzem Czerwonym i Oceanem Atlantyckim. Można je również znaleźć w części Oceanu Spokojnego, zaobserwowano je w ciepłych wodach niedaleko Hawajów, w południowej Kalifornii i Meksyku, jak również w innych lokalizacjach na Pacyfiku. Żyją zazwyczaj w morskich głębinach, czasami jednak są wyrzucane z przybrzeżnych wód i mogą występować w dużej liczbie na plażach.
21 listopada 2007 roku ogromne, szacowane na 26 km² rojowisko miliardów tych krążkopławów, zabiło ok. 100 000 ryb na farmie łososi w Irlandii Północnej[3].
Meduza świecąca, pelagia świecąca (Pelagia noctiluca) – gatunek krążkopława z rodzaju Pelagia zaliczanego do rodziny Pelagiidae.
Mesečinka (znanstveno ime Pelagia noctiluca) je majhna klobučnjaška meduza s polkrožnim klobukom izpod katerega visi 8 lovk.
Mesečinka ima škrlatno rdeč v rjavo se spreminjajoč klobuk, premera 1,5cm do 5cm. Kaže bioluminiscenco. Rob klobuka ima 16 robnih krp, 8 lovk in 8 čutnih betičev. Lovke so lahko dolge do 10 m na lovkah pa ima veliko število posebnih celic z ožigalkami. Mesečinka se potopi tudi do globine 70 m, največkrat jo pa opazimo na globini od 20-50 m.
Prehranjuje se s planktonskimi bitji, ki jih lovi z ožigalkami. Ožigalke so napoljene s strupeno tekočino. Ko se žival ali človek dotakne ožigalke, se sproži in izbrizga strup. S tem plen omrtvi in ga z lovkami spravi skozi usta v telesno votlino na spodnji strani klobuka. Neprebavljenje ostanke skozi isto votlino izloči. Ožigalke ne služijo samo za omrtvičenje plena, temveč tudi za obrambo.
Kisik sprejema skozi celotno površino.
V vodi prosto lebdi ali pa plava tako, da se poganja z razpiranjem in stiskanjem klobuka.
Živi v obrežnih vodah vseh morij, posebno v toplejših in zmernejših pasovih. Mesečinka je pogosta v Atlantiku, Sredozemskem morju. V južnem in srednjem Jadranu lahko včasih opazimo velike roje teh živali[1].
So ločenih spolov. Razmnožujejo se spolno. V meduzi nastanejo spolne celice. Po združitvi semenčice z jajčecem se razvije migetalkasta ličinka. Ker je mesečinka v svojem razvoju izgubila polipni stadij se iz ličinke v enem mesecu razvije mlada meduza.
Mesečinka (znanstveno ime Pelagia noctiluca) je majhna klobučnjaška meduza s polkrožnim klobukom izpod katerega visi 8 lovk.
Lysmanet (Pelagia noctiluca) är en manet som förekommer från nordöstra Atlanten till Medelhavet och i delar av Indiska oceanen och Stilla havet. Lysmaneten har förmåga att utsända ljus (se bioluminiscens), vilket både dess svenska namn och dess vetenskapliga artepitet noctiluca antyder.
Lysmaneten blir i genomsnitt cirka 5–6 centimeter stor (mätt över klockan), men kan bli upp till 12 centimeter, och har åtta tentakler med brännande nässelceller och fyra munarmar. Den kan brännas kraftigt nog för att det skall vara smärtsamt för en människa. Manetens utseende är ganska varierat, typiskt har den dock en i grunden nästan genomskinlig klocka med inslag av violetta till rödaktiga nyanser och samma nyanser förekommer på tentakler och munarmar. Maneten är även typiskt prydd av små prickar.
Lysmaneten lever i öppet vatten, vanligen från nära ytan och ner till ungefär 200 meter djup, men man har fångat exemplar även på djupare vatten. Den kan uppträda i stora svärmar och om maneterna vistas nära ytan, där de utsätts för retningar av vågor, utsänder de ett lite blinkande ljus vilket kan ses från fartyg nattetid. Dess föda är olika små pelagiska djur som till exempel fisklarver. Manetens utveckling saknar ett fastsittande polypstadie.
Lysmanet (Pelagia noctiluca) är en manet som förekommer från nordöstra Atlanten till Medelhavet och i delar av Indiska oceanen och Stilla havet. Lysmaneten har förmåga att utsända ljus (se bioluminiscens), vilket både dess svenska namn och dess vetenskapliga artepitet noctiluca antyder.
Pelagia noctiluca (Forsskal, 1775), Pelagiidae familyasına dahil olan bir denizanası türüdür.
Bir scyphozoandır ve açık deniz biçimine adapte olmuşlardır. 10–15 cm büyüklüğündedirler. P. noctiluca, fotosentetik olmayan, çokhücreli ökaryot bir hayvandır. Bütün tentakülleri nematosist hücreleriyle örtülüdür. Karanlıkta, uyarıldıkları zaman, vücutları hafif bir ışık yayar. Vücutları radial simetrilidir. Zararlı ve tehlikelidirler.
Wikimedia Commons'ta Pelagia noctiluca ile ilgili çoklu ortam kategorisi bulunur.
Pelagia noctiluca (Forsskal, 1775), Pelagiidae familyasına dahil olan bir denizanası türüdür.
Bir scyphozoandır ve açık deniz biçimine adapte olmuşlardır. 10–15 cm büyüklüğündedirler. P. noctiluca, fotosentetik olmayan, çokhücreli ökaryot bir hayvandır. Bütün tentakülleri nematosist hücreleriyle örtülüdür. Karanlıkta, uyarıldıkları zaman, vücutları hafif bir ışık yayar. Vücutları radial simetrilidir. Zararlı ve tehlikelidirler.
Вид досить поширений у теплих морях та океанах по всьому світу. Найбільше розповсюджений у Північній Атлантиці, Середземному морі, Червоному морі, у Тихому океані біля узбережжя Гавайських островів, Каліфорнії та Мексики.
Парасолька досягає 20-25 см в діаметрі, щупальця можуть бути до 2 м завдовжки. Забарвлення тіла ніжне, пурпурово-червоне, щупальця - яскраво-червоні. Має властивість світитися вночі. Медуза починає світитися в момент зіткнення з будь-якими предметами.
Контакт зі щупальцями медузи небезпечний для людини. Після дотику щупалець на тілі людини з'являється опік, схожий на опік кропивою, а при сильному ураженні залишає чітко виражені шрами.
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(довідка)
야광원양해파리는 원양해파리과의 자포동물이다.
이 해파리는 북대서양 지역에서 가장 잘 알려져있으며, 서식지는 북위 4도 (적도 바로 북쪽)에서 지중해와 멕시코만을 포함한 북해에 이른다.
야광원양해파리는 일반적으로 10~27°C의 수온에서 출현하지만 11°C 미만에서는 맥동을 중지한다. 서식지는 대부분 수면에서 150m의 깊이까지 다양하지만, 1400m에서 서식했다는 기록이 있다. 야광원양해파리는 밤에는 해수면 근처에서 출현하고 낮에는 더 깊은 곳에서 출현한다.
야광원양해파리는 머리 직경이 3~12cm인 상당히 작은 해파리이다. 몸색깔은 연보라색, 보라색, 분홍색, 밝은 갈색에서 노란색까지 다양하다.