We are no strangers to jellyfish: they are transparent and often float in the water like a round umbrella on the turquoise sea, especially when they are in groups, and they look spectacular from a distance.
People often classify and name jellyfish according to the differences in their umbel-like bodies: some umbrella-like bodies emit silver light, which is called silver jellyfish; some umbrella-shaped bodies are like monks' hats, which are called monk hat jellyfish;
Some umbrella-like bodies seem to be the white sails of the ship, called sail jellyfish;
Some are like umbrellas, called umbrella jellyfish;
Some umbrella-shaped bodies shine with the light of caixia, called Xia jellyfish
...... However, in taxonomy, the subphylum jellyfish phylum (also known as the pteropod phylum) is mainly divided into two major tax groups, one belongs to the hydra order, about 3000 species, including flower jellyfish (among which there are water flies living in freshwater, etc.), soft jellyfish (of which the serval pod is the most common jellyfish in China's coast), porous pods (there are porous flies living in tropical oceans), horoscopic flies (there are horoscopic flies living in tropical oceans), freshwater mothers (including the famous peach blossom jellyfish,
Hook-hand jellyfish, etc., which live in the ocean), disc-sac jellyfish (there are accustomed silver coin jellyfish, sail jellyfish, etc.), tube jellyfish (such as monk hat jellyfish), hard jellyfish (such as magnificent jellyfish) and radiation jellyfish (including sea sand flies, ear gnaces, etc.); the other belongs to the bowl jellyfish, there are about 250 species, including cross jellyfish (there are trumpet jellyfish, tall cup jellyfish, etc.),
Crown jellyfish (such as red-spotted cruise jellyfish), flag water jellyfish (common species such as Kasumi jellyfish and sea moon jellyfish), root jellyfish (including jellyfish, etc.) and cubic jellyfish (with lamp jellyfish, hand-dragged jellyfish) and so on. With the exception of a few freshwater species such as hydras and peach blossom jellyfish, they are all seafood found in oceans around the world.
"Gentle and beautiful killer"
Jellyfish bodies contain more than 90% of the water in their gums, so it's no wonder Westerners call them "jelly fish." Although the jellyfish has a kind and gentle name and a beautiful and docile appearance, it is actually a very fierce animal. The weapons they possess are daunting, the slender, ribbon-like tentacles beneath the umbrellas, their predatory and digestive organs.
Like poisonous wires, the top of these tentacles is covered with countless poisonous stinging cells, which can shoot out venom, so it is called "poisonous hands". Jellyfish ingest various organic matter in the water for food, and after the prey is stung, it will be quickly paralyzed and die. Then, the jellyfish's tentacles cling to these prey, shrink back, and suck on the polyps under the umbrella body, each polyp can secrete enzymes, quickly breaking down the proteins in the prey. Jellyfish have no respiratory organs and circulatory system, only primitive digestive organs, from the mouth into the inside, is a short esophagus, followed by a quadrangular stomach, with gastric septum, gastric filament and other structures, so the food they capture is immediately digested and absorbed in the intestine.
Would a jellyfish be so ferocious that it would swallow a person? Although there are no such reports at present, scientists believe that this is not impossible. For example, some jellyfish have tentacles tens of meters long, and are accustomed to tightly wrapping huge prey, paralyzing the prey with its poisonous stinging cells, and then calmly "enjoying".
The fact that jellyfish use this "cruel" approach to their prey is that they themselves are just a thin, weak thing, easily torn apart, unable to withstand the action of resistance when the prey is captured. Therefore, jellyfish can only avoid the danger of being torn apart by immediately injecting deadly venom into the body of the prey.
Widely distributed in the Pacific and Atlantic Oceans, the monk-hat jellyfish is a highly toxic jellyfish.
The pale blue transparent sac-like floating sac floating on the surface of the water is generally 6 to 30 cm long, with a blunt rounded tip and a blunt posterior end, and the tip is raised in the shape of a dorsal peak, which resembles the hat of a monk (i.e., a monk) who is a monk, hence the name. These floating sacs have glowing membrane crowns, which can adjust their direction and drift on the surface of the water with the help of wind, looking at them from a distance, like a warship with sails, so it is also called "Portuguese warships".
The venom hidden in the monk's cap jellyfish sting cells is as powerful as the venom of a cobra. Experiments have proved that these neurotoxins are a protein that can make biological nerves deranged, and after 6 years of refrigeration, the toxicity of the venom remains unabated. This toxin occurs quickly in the water, and small animals die immediately after being stung. A person who is stabbed can also suffer a fatal blow, and after a few minutes, the victim's blood pressure drops sharply, it is difficult to breathe, the pulse is weak, and even the heart stops beating. Because the spine cells on the long tentacles are arranged in a candibal pattern, the skin of the stinged person will also show a cannabis-like whiplash scar, which can be distinguished from the stings of other jellyfish.
Even jellyfish that can be eaten by us are dangerous animals, once stung, it will lead to redness, swelling, heat and pain, epidermal necrosis, and symptoms such as chills, irritability, chest tightness, and unbearable pain in the wound, and when severe, it can be life-threatening due to breathing difficulties and shock.
It is said that the most toxic jellyfish in the world is the box jellyfish living in australian waters, and the toxin on this jellyfish is enough to poison 60 people. Fortunately, not all jellyfish are so toxic, most jellyfish venom does not poison people, and there are even some more special jellyfish - they have no tentacles and venom at all.
<h2 class = "pgc-h-arrow-right" > flooded "jellyfish army"</h2>
Jellyfish can not only "hurt people", but also "flood", thus bringing more trouble to people. There is a large jellyfish that often appears in the waters of Japan, with a diameter of 2 meters and a weight of 220 kilograms, and the density of the distribution is said to be 100 times higher than normal. They not only caused resentment among fishermen in the northern part of honshu island in Japan, but also began to affect the fishing and fisheries in China and South Korea.
Perhaps even more frightening would have been made to know that 2013 was once called the dreaded "Year of Jellyfish" by marine biologists , a year in which jellyfish rapidly multiplied on many of the world's beaches.
As for why the "jellyfish army" suddenly flooded, it is still unknown. Some analysts believe that global heating and environmental pollution are the main culprits of the surge in jellyfish numbers. Global warming raises sea temperatures, leading to mass blooms of jellyfish. The warm ocean current carries a large number of jellyfish into the Sea of Japan. Echizen jellyfish were abundant in Japanese waters in 1958 and 1995. When they appeared this time, the average temperature of the sea was higher than the previous two times.
Because some industrial emissions often accumulate in the port area, if they contain nitrogen, phosphorus and other components, it will enrich the seawater in the area and increase the number of plankton, which provides food for jellyfish and favorable breeding conditions. In addition, ports usually build some levees and construction facilities to prevent high tides, which also provide conditions for jellyfish to grow attached.
The types of jellyfish that have erupted around the world and the scale of outbreaks vary, with Echizen jellyfish, Kasumi jellyfish, monk's jellyfish, sea moon jellyfish, and so on. One of the most noteworthy is the sea moon jellyfish, which are "invading" the world's seas.
For example, in China, in Shandong Province, Yantai Port Bureau, a wharf around a dock, there were countless jellyfish floating on the surface, layered on top of each other, stretching for hundreds of meters. These transparent moon jellyfish are sea moon jellyfish, about the size of a plate, with a diameter of about 20 centimeters, constantly shrinking their bodies in the water and floating slowly. When the sea moon jellyfish flooded Japan, it also caused even greater disasters. Because they can clog the filtration units of nuclear power plants, nuclear power plants are forced to shut down.
In Japan, the western United States, western Europe, and Australia, researchers have tracked "invasive" jellyfish and concluded that the outbreak of sea moon jellyfish is a typical invasive alien species event. Research shows that nearly a quarter of marine species in international ports around the world are "outsiders". It is possible that the marine jellyfish were transported by ship to the waters of the world. They "hitchhike" to new habitats, which are usually local
Native species have adverse effects.
Scientists believe that relying solely on natural migration, sea and moon jellyfish cannot be dispersed in so many waters around the world. Based on an understanding of the flow of the ocean and the swimming ability of the sea jellyfish, they conducted computer simulations of the movements that could occur in the 7,000 years of this jellyfish, and the only logical way for the sea jellyfish to spread around the world through ships was the only logical way.
In order to maintain stability during the voyage, ships are usually loaded with some seawater, and many marine organisms are able to "travel" around the world through ballast seawater and trade in exotic species (such as the sale of tropical fish).
When an alien species reaches a new environment suitable for them to inhabit, it will grow and multiply rapidly. When their number reaches a certain level, coupled with the water temperature, food, etc. are beneficial, they may emerge at once.
Jellyfish outbreaks require the prey on a large number of zooplankton, and the reduction of zooplankton reduces the feeding pressure of algae, which will cause algae outbreaks and changes in the structure of plankton communities, and the increase in algae may eventually lead to red tides, bringing disasters to fishery production. If this situation continues to occur, biological disasters can occur that adversely affect the balance of the entire ecosystem.
<h2 class="pgc-h-arrow-right" > rare jellyfish as gorgeous as flowers</h2>
In fact, jellyfish are not only harmless to humans under normal circumstances, but also animals that are beneficial to humans. Many bowl jellyfish are fished for fishing, such as jellyfish, which is an extremely nutritious seafood product.
Some jellyfish can act as indicators of ocean currents and are a great help in exploring the location of fishing grounds. Jellyfish's stinging cells, motility and luminescence ability are all important contents of scientists' research. Because lunar jellyfish can get information more than a dozen hours before the storm comes, scientists have simulated their sound wave sending organs for experiments to predict ocean storms. More importantly, jellyfish are also one of the main taxa of marine plankton and play an important role in maintaining the balance of ecosystems.
There are also very precious endangered species among jellyfish, and the peach blossom jellyfish, known as the "giant panda in the water", is one of them. Peach blossom jellyfish are mostly white and transparent, and some are pink, which is a type of jellyfish that grows in temperate fresh water, with a diameter of about 0.1 to 2.4 cm. They mostly appear in the early spring when the peach blossoms are in full bloom, and when they swim in the water, they resemble peach blossom petals floating on the surface of the water, hence the name. In ancient China, they were called "peach blossom fish".
As early as the thirty-seventh year of the Ming Dynasty (1609), there is a record of "peach blossom fish" in the "Guizhou Chronicle", which is the earliest record of peach blossom jellyfish in the world. The description of the peach blossom jellyfish in the "Integration of Ancient and Modern Books" in the third year of Qing Yongzheng (1726) is more detailed and vivid: "The peach blossom fish is shaped like an elm pod, the size is different, the creep swims in the water, and the movement is collected one by one, if the person holds the finger and puts it away, he does not know how to avoid people, and the same is true in the storage cup." Take the view from the water, but it is like a saliva twist, soft and complex. ”
The reason why the ancients called it peach blossom fish is because it is not only shaped like a peach blossom, as beautiful as a peach blossom, but also synchronized with the peach blossom. In fact, the peach blossom jellyfish does not only appear when the peach blossoms bloom, and the peach blossoms are gone, but exist all year round. It is only because of the strong summer sun, the high water surface temperature, and the impact of the flood, and the low water surface temperature in the winter, and there is no plankton they need, so these times they are foraging under the water and in the stone crevices, and only in the spring when the flowers bloom, the peach blossom jellyfish floats to the surface. Peach blossom jellyfish So far, there are 12 species of peach blossom jellyfish found in the world, and there are 9 species distributed in China, and they are all endemic species. Their survival range is roughly between 30 ° and 60 ° north latitude, especially in Zhejiang, Hubei, Sichuan, Henan, Jiangsu and other places in southern China. However, due to the destruction of the natural environment in which the peach blossom jellyfish live, the prospects for many species are not optimistic.
In the "Red List of Species", Chuxiong peach blossom jellyfish, Hangzhou peach blossom jellyfish, Chuanjing peach blossom jellyfish and Leshan peach blossom jellyfish are listed as near-threatened or vulnerable species, while short-handed peach blossom jellyfish, Sichuan peach blossom jellyfish and Zigui peach blossom jellyfish are listed as endangered species, and only Xinyang peach blossom jellyfish and Chinese peach blossom jellyfish are listed as non-endangered species. This situation has attracted great attention from the academic circles at home and abroad.
Among the peach blossom jellyfish in China, the peach blossom jellyfish is the most famous. This is not only because it is very rare in the world, but also because it has a beautiful legend and a beautiful story. Legend has it that before Zhaojun left the plug, surrounded by his father and fellow villagers, he boarded the dragon boat, sat on the bow of the boat, played the pipa, and drifted all the way down the Xiangxi River in the mournful sound of the piano. At this time, the peach blossoms on both sides of the stream seemed to be emotional, and they fell one after another. Zhaojun also couldn't help but touch the scene, burst into tears, and rolled a drop of crystalline tears into the Xiangxi River. Suddenly, countless colorful "small fish" appeared in the Xiangxi River, and they were intertwined with the peach petals floating in the river, which was extremely gorgeous. Someone fished up a "small fish" and put it in the palm of Zhaojun's hand, and she saw that the "small fish" was shaped like a petaled peach blossom, so she gave it the name of "peach blossom fish". When Zhaojun's dragon boat disappeared at the end of the stream, the peach blossoms on the mountain withered, and the beautiful "little fish" in the stream disappeared without a trace. Since then, the story of Zhaojun girl and peach blossom fish has been recited from generation to generation in the local area.
Peach blossom jellyfish is not only of great ornamental value, but also of academic significance. It is a relatively inferior organism, the genome is small, the analysis of genes is relatively easy, it is a better object for studying the evolution of species, and it is also a better experimental material. The study of peach blossom jellyfish has important scientific value for exploring the origin and evolutionary history of life.
Peach blossom jellyfish has received widespread attention from people, and due to the construction of the Three Gorges Reservoir, the water level of the waters that were originally suitable for the living environment of peach blossom jellyfish in Zigui has been raised and silted up, and these "giant pandas in the water" may suffer the disaster. Many people of insight have issued appeals, hoping to choose a suitable location to restore the living environment of peach blossom jellyfish and find a safe and happy new home for peach blossom jellyfish.
Fortunately, through the continuous study of peach blossom jellyfish by experts from the Institute of Immortal Biology of the Chinese Academy of Sciences, it was found that after the Three Gorges Reservoir was stored, there were still peach blossom jellyfish inhabiting multiple locations in the reservoir area, and they did not disappear because of the reservoir storage. In view of the specific cultural connotation and ornamental value of peach blossom jellyfish, the current call for the protection of peach blossom jellyfish has aroused great concern from the domestic academic community and all sectors of society, and China has begun to study specific measures to save peach blossom jellyfish and strive to save this precious species.