Why are the aurelia near the shore in the heat. It became known why there are so many dead jellyfish on Odessa beaches. Is it possible to swim in a pond where jellyfish live

On the beaches, vacationers continue to watch unusual phenomenon: the coast is still strewn with pinkish jellyfish. To see these beautiful sea ​​creatures, it was not necessary to go far into the water - a huge number of jellyfish, to the delight of the children with shovels and buckets, swam right near the shore. A specialist from the Riga Zoo told where jellyfish came from in Riga and how long this natural phenomenon can be observed.

Why are they washed ashore?

Aurelia aurita or eared jellyfish is the name of a species of invertebrate marine animals that are found in the Baltic Sea. They are round and transparent - just like bags filled with water. These jellyfish swim poorly, they can only rise and sink, hovering motionless. In the second half of summer and early autumn, especially in August-September, they can be found on the coast of the Gulf of Riga. Beautiful inhabitants of the deep sea live only a year, and only once in a lifetime they breed, and then they die. It is the half-dead or dead jellyfish that it throws ashore. So the appearance of jellyfish on the beach is not unusual.

But to meet another type of jellyfish in Latvia - hairy cyanide - can be very, very rare. But sometimes such a jellyfish can be seen in the Pape area.

Is it possible to get a burn from a jellyfish?

Aurelia is poisonous, but its poison is so negligible that it is safe for humans. Several cases have been noted severe burns from Eared Jellyfish to Gulf of Mexico at east coast America and England. Those who rested on the Black Sea say that jellyfish also sting, but the burn is light, weaker than nettle. The Baltic jellyfish cannot bite through human skin. Taking a jellyfish in hand, usually a person does not feel a bite. But still there are people with sensitive skin - for example, children. In such people, the skin may turn red and itch.

Is the presence of jellyfish a sign of clean water?

No, this conventional wisdom is not true. It is only known that jellyfish live only in salt water.


Photo: Nora Krevņeva

Is it possible to swim in a pond where jellyfish are found?

Can. But again, if the skin is sensitive, then you can get burns from the touch of jellyfish. Running barefoot on the shallows, where there are a lot of jellyfish, is also possible, but do not be surprised if your feet itch later.

Aurelia jellyfish are heterosexual creatures. Understanding who is female and who is male is very simple. On the body of males there are milky-white testicles, clearly visible and looking like half rings, females have purple and red ovaries that are visible through the bell.

In Japan and China, aurelia jellyfish are used as food; in these countries, fishing for these creatures is organized. Large aurelias are used for salting, small ones are boiled or fried. Fortunately, we do not practice such fishing in Latvia. Jellyfish die a natural death. But sometimes small fish gnaw at the dome of the jellyfish with pleasure.

In Sevastopol unexpectedly ended bathing season. The Black Sea was filled with hordes of jellyfish. With details - the correspondent of "Vesti FM" Oleg Grinev.

"Vesti FM": What's up, what's going on?

Grinev: In fact, there is still no clear explanation of the reasons why all coastal beaches are occupied by jellyfish. Two days ago, bathers discovered that, literally one meter away from the shore, they were swimming in a continuous carpet consisting of both dead and live jellyfish. The scientists took water samples. It is possible that toxins, traces of human activity, got into the water. Because of this, some of the jellyfish died out, and some simply migrated from their permanent habitats and approached the shore. As a rule, jellyfish come ashore in Sevastopol in mid-autumn, when storms begin. And why they approached now remains to be seen.

"Vesti FM": The version that the matter is only in a cold snap does not stand up to criticism?

Grinev: The version does not stand up to criticism for the reason that there is no cooling as such, even recent storms, of course, mixed the upper and lower layers, but, nevertheless, the water temperature is plus 18-19 degrees, and in some bays even reaches 20.

"Vesti FM": But everyone who has ever vacationed on the Black Sea coast knows that there are jellyfish there, but it’s just that now is probably not the season. Too early they appeared and there are a lot of them?

Grinev: Yes. Jellyfish, of course, are. They are met in any weather and at any time of the year. But the fact is that it was hundreds of thousands of jellyfish that covered all Sevastopol beaches with a continuous carpet, not only the bays, but also the beaches of Fiolent, which are constantly washed by the current, including the cold one, why this happened is still not clear. But, again, the possibility is not ruled out that sand was mined on Fiolent just two weeks ago, and thereby destroyed all the benthic fauna. It is possible that it was precisely because of this that the jellyfish were forced to migrate in order to avoid destruction by humans. It is quite possible that during the migration storms, of course, destroyed some of them, and the living ones approached the shore, where there is food for them.

"Vesti FM": Are the beaches officially closed by order of the city authorities?

Grinev: No, the beaches are not closed. There are no unsanitary conditions on the beaches, there are no toxic substances in the water, only jellyfish in the water. Jellyfish are organic. And although they do not pose a serious danger to humans, let's just say that it is unpleasant to swim when you are surrounded by jellyfish.

"Vesti FM": The administration is not going to do anything?

Grinev: So far, it is impossible to do anything - to scoop out jellyfish, very serious forces and means are needed, and given that the coastline is more than 50 kilometers long, it will take more than one day. It is much easier to wait for the next storm or hope that the jellyfish will move away on their own. But, most likely, the next wave of about three points will throw all the jellyfish ashore, and the jellyfish that can will simply go to the depths to avoid the storm.

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25.04.2019, 07:10

“Ukraine abandoned the inhabitants of Donbass”

VLADIMIR SOLOVIEV: “Putin said that these are “humanitarian measures”. But Zelensky provoked such a decision. Firstly, he not only repeated all Poroshenko’s mantras about Donbass, but managed to bring to the stage of de facto negation of the Minsk agreements that there would be no special status for Donetsk and Lugansk and there would be no amnesty.”

The painting by the French artist Theodore Gericault "The Raft of the Medusa" in 1819 attracted me primarily with its plot and the terrible tragedy that formed its basis. The gigantic canvas impresses with its expressive power, combining in one picture the dead and the living, hope and despair.

The canvas is huge. Its length is 7 m, and the width 5 m

Raft of the Medusa.

TRAGEDY IN THE SEA.

With The subject for the picture was an event that excited all of France at that time. On June 17, 1816, a small French squadron - the frigate "Medusa", the corvettes "Echo" and "Loire" and the brig "Argus" - set off from France to Senegal.

On board each of the ships were a considerable number of passengers - soldiers, officials colonial administration and members of their families. Among them were the governor of Senegal, Schmalz, and the soldiers of the "African battalion" - three companies of 84 people each, recruited from people of different nationalities, among whom there were former criminals and various daredevils. The flagship Medusa and the entire squadron were commanded by Durouade Chaumaret, an inexperienced captain who received this position through patronage.


Frigate.


Corvette


Brig.

The captain's inexperience quickly showed itself. The high-speed Meduza broke away from the rest of the ships of the flotilla and, less than a month later, ran aground near the Cape Verde Islands, 160 km from the coast West Africa. A small sand bank was clearly marked on the maps as a bright spot, but Chaumeret, who did not read sea charts well, managed to drive his ship into this particular part of the Atlantic. When the crew began to throw weights overboard to lighten the ship's weight, did the captain stop these attempts? How could state property be squandered? He decided to get to the shore in boats.

There were only six of them, and the Meduza carried about four hundred people on board. Among them were the future governor of Senegal, Colonel Julien Schmalz, his wife, as well as several dozen scientists, high-ranking military and aristocrats. It was this audience that took their places in the boats. Seventeen people remained on board the Medusa. The remaining one hundred and forty-nine with a minimum supply of food and fresh water were loaded onto a small raft, hastily put together from masts and planks.

According to all maritime laws, Chaumare, as a captain, was supposed to be the last to leave the ship, but did not. He, Governor Schmalz and senior officers were placed in boats. Several junior ranks, thirty sailors and most of soldiers and passengers simply moved to the raft. The command of the raft was entrusted to midshipman Coudin, who had difficulty moving due to a leg injury.

Those who happened to sail on the raft were not even allowed to take provisions with them, so as not to overload the raft. There were 17 people left on the abandoned frigate, who could not find a place either on a raft or in boats.

Transporting a bulky heavy raft proved to be extremely difficult. The rowers were exhausted. They, like the captain of the Medusa, who was in one of the boats, were already worried about the thought of only their own salvation - a storm was about to come. Suddenly, the rope holding the raft in tow broke. It is not clear whether this happened due to someone else's fault or if the rope simply failed.

Unrestrained, the boats with the captain and the governor on board rushed forward. Only the crew of one boat again tried to take the raft in tow, but after several failures, they also abandoned it.

Both those who were in the boats and those who remained on the raft understood that the fate of the raft was a foregone conclusion: even if it stays afloat for some time, people still do not have provisions. On the raft - without a rudder, without sails, which was almost impossible to control - there were 148 people left: 147 men and one woman, a former marque. People were overcome by a sense of hopelessness ...

As the boats began to disappear from sight, screams of despair and rage rang out from the raft. When the first stupor passed, which was replaced by a feeling of hatred and bitterness, they began to check the available supplies: two barrels of water, five barrels of wine, a box of crackers, soaked sea ​​water, - and that's all ... Soaked crackers were eaten on the first day. Only wine and water remained.

By nightfall, the raft began to sink into the water. “The weather was terrible,” the engineer Correard and the surgeon Savigny, participants in the drift on the Medusa raft, write in their memoirs. The raging waves swept over us and sometimes knocked us down. What a terrible state! It is impossible to imagine all this! By seven o'clock in the morning the sea calmed down somewhat, but what a terrible picture opened up to our eyes. There were twenty dead on the raft. Twelve of them had their feet caught between planks as they slid across the deck, the rest were washed overboard…”

Having lost twenty people, the raft rose somewhat, and its middle appeared above the surface of the sea. There they all huddled. The strong crushed the weak, the bodies of the dead were thrown into the sea. Everyone looked eagerly at the horizon in the hope of seeing the Echo, the Argus, or the Loire rushing to their aid. But the sea was completely deserted...

“Last night was terrible, this one is even more terrible,” Correard and Savigny write further. “Great waves crashed into the raft every minute and boiled furiously between our bodies. Neither the soldiers nor the sailors doubted that their last hour had come.

They decided to lighten their dying moments by drinking themselves unconscious. Intoxication did not take long to create confusion in the brains, already upset by the danger and lack of food. These people were clearly going to finish off the officers, and then destroy the raft by cutting the cables connecting the logs. One of them, with a boarding ax in his hands, moved to the edge of the raft and began to cut the fastenings.

Action was taken immediately. The madman with the ax was destroyed, and then a general squabble began. In the midst of a stormy sea, on this doomed raft, people fought with sabers, knives, and even teeth. Firearms the soldiers were taken away when landing on a raft. Through the wheezing of the wounded, a woman's cry broke through: “Help! I'm sinking!"

This was the cry of a canker who had been pushed off the raft by the rebellious soldiers. Correar rushed into the water and pulled her out. In the same way, junior lieutenant Lozak ended up in the ocean, and they saved him; then the same disaster with the same outcome fell on the lot of midshipman Coudin. It is still difficult for us to comprehend how an insignificant handful of people managed to resist such a huge number of madmen; there were probably no more than twenty of us fighting with all this rabid army!

When dawn came, 65 people were counted dead or missing on the raft. A new misfortune was also discovered: during the dump, two barrels of wine and two barrels of water, the only ones on the raft, were thrown into the sea. Two more barrels of wine had been drunk the day before. So for all the survivors - more than sixty people - now there was only one barrel of wine left.

Hours passed. The horizon remained deadly clear: no land, no sail. People began to suffer from hunger. Several people tried to organize fishing by building tackle from improvised material, but this idea was unsuccessful. The next night was calmer than the previous ones. People slept standing up, knee-deep in water, closely clinging to each other.

By the morning fourth day a little over fifty people remained on the raft. A school of flying fish jumped out of the water and flopped onto the wooden deck. They were quite small, but very good in taste. They were eaten raw... next night the sea remained calm, but a real storm raged on the raft. Some of the soldiers, dissatisfied with the established portion of wine, revolted. In the midst of the darkness of the night, the massacre boiled again ...

By morning, only 28 people remained alive on the raft. " Sea water corroded the skin on our feet; we were all bruised and wounded, they burned from salt water, forcing us to scream every minute, - Correar and Savigny say in their book. There was only four days of wine left. We calculated that if the boats were not washed ashore, they would need at least three or four days to reach Saint-Louis, then still need time to equip the ships that would go looking for us. However, no one was looking for them ...

Wounded, exhausted, tormented by thirst and hunger, people fell into a state of apathy and complete hopelessness. Many went crazy. Some have already gone into such a frenzy of hunger that they pounced on the remains of one of their comrades in misfortune ... “At the first moment, many of us did not touch this food. But after a while, everyone else was forced to resort to this measure.

On the morning of July 17, a ship appeared on the horizon, but soon disappeared from sight. At noon he reappeared and this time headed straight for the raft. It was the brig Argus. A terrible sight appeared before the eyes of his crew: a half-sunken raft and on it fifteen emaciated to the last extreme, half-dead people (five of them subsequently died). And fifty-two days after the disaster, the Meduza frigate was also found - to everyone's surprise, it did not sink, and there were still three living people on board from among those seventeen that remained on the ship.

Among those rescued on the raft were officers Correard and Savigny. In 1817 they published notes about these tragic events. The book began with the words: "The history of sea voyages knows no other example as terrible as the death of the Medusa."

This publication had the widest resonance. France was amazed that its enlightened citizens could descend to cannibalism, eating corpses and other abominations (although, perhaps, there is nothing particularly surprising here - after all, the passengers of the Medusa grew and formed in a bloody era of revolution and continuous wars).

A considerable political scandal also broke out: the liberals hastened to blame the royal government for the tragedy of Meduza, which had poorly prepared the expedition.

THE ARTIST'S WORK ON THE PICTURE.

In November 1818, Gericault retired to his studio, shaved his head so that there was no temptation to go out to social evenings and entertainment, and devoted himself entirely to working on a huge canvas - from morning to evening, for eight months.

The work was intense, a lot changed along the way. For example, having spent so much time on gloomy sketches, Gericault hardly used them for the painting itself. He abandoned pathology and physiology in order to reveal the psychology of doomed people.

On his canvas, Gericault creates an artistic version of events, but very close to reality. He unfolded on a raft, overwhelmed by waves, a complex scale psychological states and the experiences of people in distress. That is why even the corpses in the picture do not bear the stamp of dystrophic exhaustion and decomposition, only the accurately conveyed stiffness of their bodies shows that the audience is dead.

At first glance, it may seem to the viewer that the figures are located on the raft somewhat chaotically, but this was deeply thought out by the artist. In the foreground - the "frieze of death" - the figures are given in full size, here people are shown dying, immersed in complete apathy. And next to them are already dead ...

In hopeless despair, the father sits by the corpse of his beloved son, supporting him with his hand, as if trying to catch the beating of a frozen heart. To the right of the figure of the son is the corpse of a young man lying head down with his arm outstretched. Above him is a man with a wandering look, apparently losing his mind. This group ends with the figure of a dead man: his stiff legs are caught on a beam, his hands and head are lowered into the sea.

. The raft itself is shown close to the frame, and therefore, from the viewer, which involuntarily makes the latter, as it were, an accomplice in tragic events. Dark clouds hung over the ocean. Heavy, huge waves rise to the sky, threatening to flood the raft and the unfortunate people crowded on it. The wind tears the sail with force, tilting the mast held by thick ropes.

In the background of the picture is a group of believers in salvation, because hope can come to the world of death and despair. This group forms a kind of "pyramid, which is crowned by the figure of a Negro signalman, trying to attract the attention of the Argus brig that has appeared on the horizon." frieze of death" it was dark, then towards the horizon - a symbol of hope - it becomes lighter.

HOW DID YOU RECEIVE THE PICTURE?

When Géricault exhibited The Raft of the Medusa in Salone in 1819 , the picture aroused public outrage, since the artist, contrary to the academic norms of that time, used such a large format not to depict a heroic, moralizing or classical plot.

Highly appreciated the painting by Eugene Delacroix , who posed for his friend, witnessed the birth of a composition that breaks all the usual ideas about painting . Delacroix later recalled that when he saw the finished painting, he“In delight, he rushed to run like crazy, and could not stop until the house”.

After the artist's death in 1824, the painting was put up for auction and purchased by his close friend, the artist Dedreux-Dorcy, for 6,000 francs, while the representatives of the museum in the Louvre were not ready to go beyond 5,000. Dedreux-Dorcy subsequently turned down an offer to sell the work in the United States for a much larger amount and eventually gave it to the Louvre for the same 6,000 on the condition that it be placed in the main exhibition. The Raft of the Medusa is currently in the Louvre.

There is no hero on Gericault's painting "The Raft of the Medusa", but nameless people, suffering and worthy of sympathy, are immortalized.In this picture, Gericault was the first to raise the theme of humanity to the romantics and demonstrated an exceptional realistic style of painting.

FATE OF THE CAPTAIN:

Captain 1st Rank Jean Duroy de Chaumare appeared before the tribunal, was dismissed from the Navy and sentenced to prison for three years. In the regions where he lived out his life, everyone knew about his "exploits" and treated him with contempt and hostility. He lived long life, died at 78, but longevity was not a joy to him. He had to spend the rest of his life as a recluse, as he had to listen to insults everywhere. His the only one the son committed suicide, unable to endure his father's shame ...

Artist Theodore Géricault died at the age of 32 as a result of a fall from a horse.

YOUR OPINION ABOUT THE PICTURE AND THE TRAGEDY WHICH FORGED IN ITS BASIS?

(Write about what touched you the most)


And now - let's take our eyes off the bottom and look around the turquoise water column - many marine animals spend their whole lives in it, trying not to approach either the bottom or the surface. Among them there are excellent swimmers - pelagic fish, whose whole life is in motion, and slow creatures carried by currents. Of these living floaters, we most often meet jellyfish and ctenophores.


Jellyfish


There are two species in the Black Sea large jellyfish - aurelia, similar to an umbrella, andcornerotwith a fleshy mushroom-shaped dome from which heavy lacy mouth-lobes hang down. The dome of the cornerot can reach 70 centimeters in diameter, such a jellyfish is long more than a meter! Aurelia appear off our shores in early spring, there are many of them in the sea all summer; by autumn - they are forced out by mighty cornerots.

We don't really like jellyfish - they are slippery and they sting. This is true. But let's dive in and cast a glance at them from under the water - how merrily the thin umbrellas of aurelia play in the rays of the sun, as in crystal chandeliers, the light is magically crushed in the huge bells of the cornerots! From time to time they wave their domes - straighten and shorten them, pushing themselves up. Jellyfish do not know how to move quickly - they are carried along the sea by the will of the currents, and sometimes the waves wash their countless numbers ashore.
Jellyfish live in the water column, here they catch with their tentacles their small moving food - plankton. Sometimes larger animals come across, the jellyfish draws them into the stomach - and it is transparent, like her whole body, and, like flies stuck in amber, we see digested fish and crustaceans embedded in the dome of the jellyfish. To make it easier for them to soar in the water, the jellyfish themselves are almost entirely composed of it. But still, if they did not push themselves up, they would eventually sink to the bottom, contact with which is death, their jelly-like bodies are so tender. Further from the bottom - closer to the light, closer to food - plankton, inhabiting the upper 30-50 meters of the sea. This is main law jellyfish life.

In order to know where the bottom is and where the surface is, jellyfish have balance organs - statocysts - sacs with sensitive hairs in which grains of sand roll. The position of the grain of sand in the statocyst indicates the direction down to the bottom, which means that you need to swim in the opposite direction. And the eyes that distinguish the level of illumination indicate the way up - to light and food. Too bright light already scares off the jellyfish - it means that the waves are very close, which can damage its soft body. The eyes and statocysts of jellyfish, together with the olfactory fossa, are collected into single organs - ropalia - there are many of them, and they are located along the edge of the dome of the jellyfish. Strange as it may sound, jellyfish - not all their lives - jellyfish, but two more animals that are completely different from either jellyfish or each other. Unclear? Let's look at the life story of Aurelia.

Four white semicircles forming a wide cross in the Aurelia umbrella, the testes of the males of these jellyfish. And in females, pink-purple ovaries are visible in the dome. Males fertilize eggs, and they develop in the body of females - take a closer look, in the photographs of some aurelias you can see her orange clusters under umbrellas. From the eggs come covered with ciliaplanula larvae, they circle in the water, eating the smallest plankton. Having gained weight, the planulas sit on the bottom and turn intopolypwith a mouth surrounded by tentacles. The Aurelia polyp is tiny and hard to find in the sea. From the upper part of the polyp, new jellyfish bud and float into the sea - the wheel of life of Aurelia has made a full turn.

And aurelia and cornerotbelong to the classscyphoid jellyfish- they are large. But there are several other species in our seahydroid jellyfish– you can’t see those without a microscope, and we will get to know them by studying the Black Sea plankton.

In other intestinal cavities - sea anemones, which we will meet on stones, the polyp is large and strong - this is the main, long-lived, stage of its life cycle. So who is the sea anemone - that polyp that looks like a luxurious blue or red flower that we find under stones in the sea, or a planula larva circling in the water column?
What is Aurelia: a plate jellyfish, found everywhere near the coast, or a ciliated planula? Or is she a polyp with tentacles?
What is a crab - a bottom dweller in a powerful shell, a lover of dead mollusks, or a microscopic crustacean that catches unicellular algae in plankton?
From the point of view of biology, this is one and the same organism, but its essence is different - with a different way of life and different habitats, occupying different ecological niches. What is the meaning of such complexity? Perhaps in the fact that, living differently on different stages life cycle, the organism depends in different ways on environment. For example, there are many predators in the water column - planktonic larvae die, but the bottom stages of the life cycle survive. This is just one of the possible explanations - try to come up with your own.

Jellyfish immobilize or even kill their prey with the help of stinging cells, in which, coiled with a tight spring, a capsule with poison is hidden and a sharp and jagged spear extending from it. The spring straightens, and the poisoned spear plunges into the body of the victim when it touches a sensitive hair on the surface of the stinging cell - a kind of trigger, or cock of this weapon. In the body of the victim, the sharp tip of the hollow spear breaks off, and paralyzing poison pours out of it, like from a tube. The stinging cage is a one-time weapon: once fired, it bursts and dies.

Batteries of poisoned harpoons are located near the aurelia in the fringe of tentacles surrounding its umbrella, and at the cornerot they are on the beard of the oral lobes hanging under the dome. It is interesting that the shiny big-headed fry of the horse mackerel often crowd in a whole flock between the mouth lobes of the cornerot, travel with the jellyfish - and stinging cells mysteriously do not care for them. Just like clownfish live among the deadly tentacles of tropical anemones.
For a small planktonic crustacean, one blow with a poisonous dart of a jellyfish or sea anemone is enough to stop fluttering. Now imagine how many sensitive hairs you touch, how many times you pull the trigger when you touch a jellyfish in the water with your shoulder!


Ctenophores are living rainbows


They are magically beautiful creatures. They fill the waters of the Black Sea, starting from April - transparent, weightless, sunny weather shimmering with all the colors of the rainbow. Not jellyfish, not even their relatives, they don't look like anyone else. A separate type of animal kingdom -ctenophores!

Watch them from boats, piers, coastal cliffs, even better - from under the water. They are openwork and light, like Chinese lanterns. See how they swim - they don't wave their skirt-blades like jellyfish, but just ... move. Sparkling cords run along the body of the ctenophore - these are rows of rowing plates, they are so thin that the light passing through them is split into rays different colors- and each of the thousands of records plays with gem flashes. The rowing wave begins at the top of the animal and runs to the other end of the body, the ctenophore swims - and it seems to us that a multi-colored electric discharge slips through it. Comb jelly is mesmerizing.

If you want to take a closer look at it - do not take the ctenophore with your hand, it is so tender that it will immediately tear; it is better to scoop it out of the water with some kind of dishes or a boat folded from the palms. But still, it is best to look at ctenophores in their native environment - sometimes weak waves bring them to the shore unharmed.
The ridge plates of the ctenophore are nothing more than microscopic cilia glued together in rows, side by side, the same as those of ciliates; this type of movement betrays in them very primitive animals. Of the sense organs, they have only an organ of balance, such as a statocyst, on the top of their head. There are ctenophores with lasso tentacles, which they throw into the water so that as much as possible of small plankton, on which they feed, will stick to them.

Such is the little one living in the Black Sea for a long timepleurobrachiaand appeared here 20 years ago a largemnemiopsis.

And there are ctenophores without tentacles, predators that eat other ctenophores - only ctenophores and no one else; they are floating stomachs, one side of the body of which is a mouth that opens to swallow the victim. Since the mid-1990s, there has been one such comb jelly in the Black Sea -Beroe.
The appearance of Mnemiopsis in the Black Sea in the 1980s led to ecological disaster- so much plankton he ate and so multiplied; detailed history the conquest of the Black Sea by Atlantic ctenophores, see the chapter on the properties of the Black Sea.
During the day they sparkle like underwater rainbows, and at night they glow! These are the largest luminous animals of the Black Sea, and, swimming on a summer night, you can be a little scared when a green flash suddenly blazes next to you, in the black water - you touched a comb jelly.
At night, underwater, shimmering silent green light, comb jelly resembles a magic lamp; touch it with your finger and the fading light will flare up with renewed vigor.

Why jellyfish swim to the seashore, you will learn from this article.

Why do jellyfish swim to shore?

Jellyfish swim to the shore to leave offspring. Their total invasion in shallow water, closer to the coast - this is just a temporary phenomenon. Having taken care of their future, they swim back deep into the depths of the sea.

Why are there many jellyfish in the sea?

There are not always many jellyfish in the sea, but often the coast is overflowing with such inhabitants. This means that jellyfish have a mating season

Jellyfish are one of the most ancient inhabitants of our planet. They appeared more than 650 million years ago. And in the process of evolution, they have changed little. 95% of these animals are made up of water, and 5% of the muscle fibers in their body makes jellyfish a complete organism.

Three types of jellyfish can be found in the sea:

  • Aurelia

She is also called " eared jellyfish". And all because there are transparent white tentacles around the entire circumference of the aurelia. This is the most small view jellyfish A feature of the animal is the presence of stinging cells in the body, which can damage the edges of the lips and the mucous membrane of the eyes.

  • Cornerot

By appearance it resembles a fleshy bell or dome with a heavy beard of oral cavities. Lacy blades are equipped with poisonous stinging cells. It is better to swim around such jellyfish.

  • Mnemiopsis

This type of jellyfish does not have stingers or tentacles. In the Black Sea, it is the smallest. Its feature is the ability to glow. Therefore, another name for Mnemiopsis is nightlight.

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