Pelagia noctiluca
The beauty of the underwater world is that the distribution of life and various species is distributed 360° along the entire water column, even if not exactly uniformly. Marine biologists divide marine life into three macro-categories based on where they live and how they move, or rather into three marine biological categories: Plankton, Nekton and Benthos. Pelagia noctiluca Medusa luminosa viola Mauve stinger intotheblue.it
Nekton is the set of all organisms defined as “swimmers“, capable of moving autonomously and effectively overcoming the motions of the sea, such as waves and currents. The benthos (from the Greek “deep“) includes all those organisms, animals and plants, whose life is linked to the seabed, that is, which in some way contract relationships with it. Plankton includes the organisms that float in the water and are transported by currents and wave motion. However, there are cases in which the division between these three categories is not so clear.
So when we dive in the blue we must consider that marine life can be present anywhere, not just on the seabed that we go to explore on most dives. This is precisely the case of what we call the “wanderers of the sea“, i.e. those plantonic species (Plankton in ancient Greek means “wandering“, “wanderer“), that is, transported by sea currents, such as: shrimps, fish in the larval state, snails capable of floating, larvae of sea urchins and crabs, jellyfish.
In the video we are in the descent phase of a dive to a seabed of approximately 48 meters deep, and halfway down the descent, that is, at approximately 20 meters deep, we encountered an isolated specimen of Pelagia noctiluca, infamous for the painful irritations it causes, purple jellyfish or luminous jellyfish. Let us remember that this jellyfish is a pelagic species, which approaches the coast in spring, summer and autumn, transported by marine currents.
The Luminous jellyfish (Pelagia noctiluca) is a jellyfish of the Pelagiidae family.
Distribution and habitat
It is common in the Mediterranean Sea and the eastern Atlantic Ocean up to the North Sea; it has been mentioned in the news for its abundance in our seas in some periods and for the painful irritations it causes if touched.
Description
Brown-pink or pink-violet umbrella of about 10 centimeters in diameter, translucent, composed of 16 lobes from which 8 long retractable tentacles, very stinging and semi-transparent, start from the edges and can extend up to 2 metres. The oral arms, the same color as the umbrella, are up to about 30 centimeters long. The attribution of the genus noctiluca (from Latin) as it emits flashes (bioluminescence) of greenish light, visible especially at night.
Biology Nutrition
It feeds on plankton and small fish which it captures using its tentacles equipped with stinging nematocysts.
Reproduction
P. noctiluca is one of the jellyfish that does not go through the polypoid stage during maturation. The adults have separate sexes: the female lays her eggs in the sea, which are fertilized by the sperm of the males. The planula is born from the zygote, a larva equipped with cilia for movement and which disperses at a planktonic level. However, it does not go through the scyphistoma stage, anchoring itself to the ground, but divides directly into ephyra, a young jellyfish which will then grow to form the adult jellyfish.
https://it.wikipedia.org/wiki/Pelagia_noctiluca
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