Although sea ​​fish They drink a lot of water; their freshwater relatives drink almost nothing. The root of this difference lies in the need of fish to maintain a normal balance of salt and water in the body.

The water in the ocean is three times saltier than the own liquid environment of the fish living in the ocean. Through a natural process known as osmosis, water from a marine fish's body flows out through its skin and gills. To replace lost fluid, saltwater fish are forced to absorb a large number of sea ​​water.

The concentration of salt in the body of freshwater fish exceeds its content in the surrounding aquatic environment, therefore freshwater fish do not drink like sea fish, but constantly absorb water through the skin. They excrete excess fluid in the form of excessive urination.

1. The amount of water that marine fish absorb depends on the degree of salinity. The saltier the water, the more fish drinks.

2. The gills of fish that live in salt water absorb some salt.

3. By osmosis, fish can pass large amounts of water through their gills.

4. Excess salt is excreted in the urine.

5. Water swallowed by saltwater fish is absorbed by the intestines.

Freshwater fish secrete salt and absorb water through their skin, so they don't need to drink water. The level of salt in the body of freshwater fish is replenished with food and ions (salt) deposited in the gills.

1. Driven by the force of osmosis, water enters the fish's body through the gills.

2. Some of the salt is lost by the gills as a result of osmosis.

3. Freshwater fish have excess water, which they excrete as very dilute urine.

If the fish are swapped

In their usual home, sea fish maintain a normal water-salt balance by drinking large amounts of water and excreting excess salt. In fresh water sea ​​fish absorbs water, diluting the liquid environment of its body with it. Unable to retain salt or get rid of excess water, the fish dies.

Usually freshwater fish regulates the level of salt in the tissues of its body by absorbing salt and releasing water. In salt water, fish lose water that they cannot replace; The salt content in her body rises to lethal levels.

Fickle natures

Several species of fish are diadromous, meaning they can live in both salt and fresh water, adjusting their body fluids to suit conditions. environment. They drink water - or abstain from it - depending on the salt concentration in their habitat. In addition, their gills and kidneys are able to quickly switch from processing salt water to fresh water, and vice versa. Salmon, which live in the ocean and spawn in rivers, as well as sturgeon, panther and lamprey, which live in river mouths, are also among the easily adaptable fish. Some species of diadromous fish are shown in the illustration above.

1. 1. LIFE IN THE CRADLE OF LIFE If you look at our earth from space, we will see that it is not land at all, but water - the World Ocean. The oceans account for 73% of the planet's surface, while land accounts for only 27%. The world ocean consists of five water giants: in addition to the largest Pacific, there are also the Atlantic, Indian and Arctic. So it would be more correct to call our planet not the Earth, but the Ocean. Life on our planet began not on land, but in the ocean. Ocean water tastes bitter and salty, it contains everything chemical elements and their compounds, necessary for the existence and development of all life on the planet. Taste a drop of your sweat - it's salty. Lick the blood when you get hurt - it's also salty. This is the influence of the ocean, from which all land living creatures once emerged. The human body is 63% water, our blood is 92% water. Without water there is no life. What are seas? These are essentially coastal bays of the World Ocean. Russia can be called a great maritime power. In the south, Russian dry land is washed by Black and Sea of ​​Azov, in the west - the Baltic, in the north - the seas of the Arctic Ocean (Barents, White, Kara, Chukotka), in the east - the Pacific Ocean (Bering, Okhotsk, Japan). The Caspian Sea, which has no access to the World Ocean, stands apart. Life in sea and ocean waters is rich and diverse. All types of fauna are represented in salt water, and out of more than sixty classes of animals, about sixty live in water. On our planet there are two environments in which life is possible: air and water. We live in the air - in the atmosphere. The aquatic environment is called the hydrosphere. The hydrosphere is populated by more than
2. 2. 4 EXPERIENCE THE WORLD LIFE IN THE CRADLE OF LIFE 5 have lost the ability to live outside of water. Only breathing atmospheric air now connects both of them with their former homeland - air environment. The former include pinnipeds, and the latter cetaceans. Pinnipeds live and feed in water, and go to the shore or ice to rest and reproduce. Therefore, their legs gradually transformed into flippers. Pinnipeds are divided into two characteristic groups according to the degree of adaptability to life in the aquatic environment. The legs of animals of both groups are shortened and turned into rowing limbs. And the hind ones have changed in different ways in connection with life in water. Thus, walruses move on land, relying on both their forelimbs and their hind limbs - a reminder that their ancestors were once denser and more uniform than the atmosphere. And the Dilis live on dry land. And in real seals, of course, there is not one, but two groups of living creatures in it. Some of them have completely lost the ability to support their bodies; others are secondary water. on land: when the Caspian seal moves along the su Primary waters are those that are in the process of evolution, only the front flippers are involved in this, the rear flippers have never left the hydrosphere. Their character is folded, raised, the body drags on its belly. The thorny trait is the ability to breathe oxygen dissolved in water. Among secondary aquatic animals, say, the seal or the walrus, the ancestors lived and evolved on land, and then again adapted to life in the hydrosphere. Primary aquatic organisms include, say, the Antarctic sponge; Looking at it, you won’t even immediately understand whether it is an animal or a bright underwater flower. Some of the sea animals even have “plant” names, such as the sea lily. Sea anemones, a type of sea coral, also look like amazing flowers of the sea. We will return to all these sea inhabitants later, but for now let’s turn to the secondary aquatic population of the hydrosphere. Let's start with aquatic mammals, whose ancestors certainly lived on land. Some of these animals once, a long time ago, lived on the coasts, and then chose two environments as their habitat: air and water, and some became so adapted to life in the aquatic environment that they at all
3. b DISCOVER the world LIFE IN THE CRADLE OF LIFE 7 dolphins blue whale The most perfect adaptation to life of fin whales in the aquatic environment, of course, is in cetaceans - they completely lost contact with the shore, and their development proceeded differently than in pinnipeds: the hind limbs make up a group of toothed whales - these are sperm whales, the bones have disappeared, and the tail (missing) At lastono whales, dolphins. Others lost their teeth, instead of them gih) turned into a powerful caudal fin, special plates grew - whalebones, through their purpose and shape they resemble such a whale, which is captured in a huge mouth, like the fin of fish, only located not in the direction of water, while all living things are the smallest crustaceans, in a vertical plane, but in a horizontal plane. the schools of fish remaining in his mouth make up the whales. They are also divided into two groups. Only whales are his food. A huge blue whale, for example, during the transition to life in the aquatic environment, retained its teeth and a body of 30 meters in length and a mass of 130 tons, completely
4. 4. 8 DISCOVER THE WORLD LIFE IN THE CRADLE OF LIFE 9 is adapted to feed on tiny sea crustaceans, which, however, in the sea are concentrated in schools of hundreds of thousands of individuals. The fin whale behaves in the same way, capturing whole schools of herring, capelin, and other fish into its filtering apparatus. small fish. Speaking about the inhabitants marine environment, let's talk about birds... Some of them gradually connected their lives with water. It's about about those birds that obtain food only in the aquatic environment, which means they can successfully pursue prey in the water. Penguins undoubtedly hold the record for adapting to life in the aquatic environment - they have completely lost the ability to fly, their wings have turned into perfect flippers. The penguin moves in water at a speed of 10 meters per second and is capable of diving to a depth of 130 meters. There are 16 species of these underwater birds, all of them are excellent swimmers, even the most fast fish. The second most adaptable bird inhabitant of sea water can be called petrels, especially those species that live in Southern Hemisphere. Their entire life (except for the period of incubation of eggs) is spent at sea. These birds sleep on the waves and drink salty sea water. They are usually active at night, when the smallest crustaceans, and after them the squid that feed on them, rise to the surface. The diving petrel uses its wings as fins, stays under water for up to 2 minutes, swims up to 300 meters during this time, dives
5. 10 DISCOVER THE WORLD LIFE IN THE CRADLE OF LIFE 11 dive to a depth of 5 meters, swimming in water more than 100 meters. They row with their wings. The edges dive for herring from a height and dive to 30 meters, rowing underwater with their wings and legs. Guillemots dive to the same depth and swim very quickly, and their wings are equally well adapted to both air and water environments. They steer in the water with their paws. Arctic loons swim more than 20 km underwater per day, sometimes diving to a depth of 10 meters. These birds have not lost contact with land; on land they multiply. But it is on land that they are very clumsy - their body is adapted to hunting in the aquatic environment. In puffins, the legs are so shifted H~&D that this bird To move on land, you have to raise your body high, but in water these legs provide the puffin with rapid movement to a depth of 9 meters. Cormorants also dive to the same depth. Petrels and eiders are not afraid of storms or surf. They pierce the rising waves, catching their prey on the fly. Eiders can ~ " ~.
6. 6. They fall onto the shore, the splashes from them form puddles on the low banks and wet the stones. The second floor is called littoral (from the Latin litoralis - “shore”). Under the influence of the attraction of the Sun and Moon, the surface of the sea rises and falls. Twice a day, tidal currents either advance on the shore or roll away from it. In the Black Sea, this fluctuation in water level is only 13 cm, and in the ocean it can range from 2 to 16 m. Some algae, crabs, mollusks, and sea worms have adapted to live on these two floors. INVERTED SKYSCRAPER When we begin to study the sea, it turns out that its inhabitants are far from indifferent to where exactly they are. Some plants and animals are located near the surface, others prefer deeper zones. And there are also those that live at the very bottom; it turns out to be huge and populated. a skyscraper, only seemingly upside down, going deep into the depths, and each floor has its own population. On the ground floor there is a surf zone. Under the influence of the wind, sea waves roll rhythmically
7. 7. 14 DISCOVER THE WORLD The third floor of a sea skyscraper will be the coastal zone that is not exposed during low tide. This floor extends down to the level where the thicket of plants ends. This is the floor most populated by marine organisms; there is enough light and a lot of food. The depth of the lower level of this floor depends on the transparency of the water in the sea. In the Barents Sea, in many tropical seas, the lower boundary of this floor is at a depth of 250 m. On the fourth floor there are no plants - here is the kingdom of echinoderms and sponges. This floor goes to a depth of 400m. From the fifth floor the deep sea area begins - up to one kilometer. There are many attached animals that resemble plants. The lower the floors, the less populated they are. Of the 140 thousand species of marine animals known to science today, most live on the first four floors, on the fifth there are no more than 600-700 species, and at a depth of 10 km - no more than 120. Sponges are found to a depth of 7000 m, sea ​​stars- up to 7230 m, shrimp - up to 9000 m, sea anemones and mollusks - up to 9300 m. The lowest floors are dominated by polychaete worms, brittle stars, and holothurians. Pisces inhabit all floors except the last, but, of course, deep sea fish completely different from those that inhabit the first four floors. Currently, the greatest depth from which it has been possible to catch fish is a little more than 7 km. Plants in our skyscraper are located only on the first three floors, mainly on the second and third. Why? Because plants need light to exist. And light penetrates the water to a relatively small depth, which is lower, the lower the transparency of the water in a given area. IN Pacific Ocean limit value transparency - 60, in the Indian Sea - 50, in the Baltic Sea - not. more than 13 meters. At a depth of 1000-1500 m there is a twilight zone, and then complete darkness reigns.
8. 8. FOOD PYRAMID OF THE SEA Marine meadows and forests All seaweed are divided into three groups: green, brown and red. Scientists have calculated the biomass of planktonic algae in seawater; it amounts to an astronomical figure of one and a half billion tons. On the 3rd day, algae create the same biomass that they themselves have. Naturally, with such gigantic productivity, they provide food for a huge number of animals. Diatoms are single-celled organisms surrounded on the outside by a shell of silica. The shape and structure of these shells is amazing; it resembles the creation of a skilled artist, precious jewelry. This beauty was first seen in the 15th century, when the microscope was invented. These algae live alone or in colonies different forms- threads, ribbons, stars are sometimes so large that they are visible to the naked eye. Diatoms reproduce by fission and swim near the surface, usually no deeper than 100 m. Other microscopic algae are also present in ocean plankton. Brown algae are multicellular plants, but among them there are very tiny ones, indistinguishable without magnifying instruments, and giants up to 50 m long. These algae are common in all seas from the Arctic to the Antarctic. The most famous of these algae is kelp. It usually grows on the littoral floor and prefers cool waters with strong currents. Laminaria, especially kelp from the eastern seas (Okhotsk, Japan), are used for food. They are preserved like “seaweed” and sent for chemical processing to obtain iodine and other valuable drugs. "
9. 9. 18 DISCOVER THE WORLD FOOD PYRAMID OF THE SEA 19 Thallasiophyllum thalli resemble the fan leaves of palm trees - they are dotted with small holes. Agarum has the same perforated thalli. This algae is common in the Pacific Ocean. Macrocystis has a more complex structure: a branched trunk, on the “branches” - something similar to leaves and bubbles with air. The length of these “branches” reaches 50 m. The main part of them, thanks to bubble-floats, sways near the surface. This algae is a valuable raw material for the chemical industry. Different types algae Sargassum algae Fucus has branched thalli usually with air bubbles and grows in the northern and eastern seas of Russia, even in the desalinated water of the Baltic Sea. Fucus trees are used as fertilizers, as livestock feed, feed flour and various chemical products are made from them. A group of sargassum stands apart among the brown algae. These algae abound in the area of ​​the Atlantic Ocean called the Sargasso Sea. This sea is a huge accumulation of intertwined algae, which slowly rotate under the influence of the current at the surface. And under these thickets there is a depth of 4-6 km. In weak winds, sailing ships got stuck in Sargassy, ​​and even today not all ships are able to break through this underwater jungle. Red algae, purple algae, are predominantly saltwater plants. They contain special pigments of red and of blue color, giving them
10. 10. 20 DISCOVER THE WORLD FOOD PYRAMID OF THE SEA 21 unique coloring. They are found in the seas, but not only are they connected with the sea, with salt water everywhere, they settle on hard surfaces, you. In the surf zone along tropical shores they grow their own and sometimes on other algae. shaped low trees - rhizophora and other types of Coralline algae are known to be part of this family. They form a special type of marine runoff in the formation of coral life - mangroves. All of them are, in the fullest sense, fauve trees. They are found everywhere. Phyllophosa and amphibians, they are then flooded sea ​​water, then - in feltia - valuable algae, their fishing is carried out during low tide - they stand out of the water. They differ in the Black, White and Far Eastern seas, of which the usual method of reproduction is viviparity: they obtain agar - a valuable substance for food, and the steam germinates in the fruit still hanging on the tree. Fruit of the perfumery and pharmaceutical industries. plants are pointed, sometimes up to 1 m long. Through Most large group- these are green seedlings six months to a year that come off under the force of gravity, algae, there are about 20 thousand species of them. they fly down and, like spears, pierce into the mud. Those that are not Most green - both unicellular, colo were able to firmly stick in, carried away by a tidal wave, nial, and multicellular - are common and can rush along the waves for a year until they stumble upon fresh water. Stranded in all seas from the Arctic to the Tropics. Mangrove trees are superbly adapted to life at the boundary between the atmosphere and the hydrosphere. seaweed. in the lion it is larger in size, its lamellar thallus reaches several centimeters. This is one of the common algae in the shallow waters of the Black and Japanese seas. Locals call her sea ​​salad. We will also briefly get acquainted with higher flowering marine plants, which belong to secondary aquatic organisms. Very few of the flowering plants descended from the land into sea water. This is primarily a common herb, or eelgrass, or seagrass. Its roots go deep into the ground, and its ribbon-shaped leaves sway in the water. It grows at a depth of 1 to 10 m. Zostera leaves, after drying, are used to stuff mattresses and upholstered furniture, and in Mexico, zostera is used as food. Posidonia, which grows in the Mediterranean Sea, Atlantic and Pacific oceans, is very similar to Zostera. Ruppia, a completely inconspicuous plant with thin string-like leaves, also belongs to sea grasses. Its flowers are pollinated by water. Ruppia marinea grew in abundance in the reservoirs of salty springs of Staraya Russa. A number of species live along the Pacific coast.
11. 11. TENANTS OF ALL FLOORS We will begin our study of the animal world of our inverted skyscraper from the first floor - from the surface. And, as in the case of algae, the first object of our attention is tiny creatures that can only be seen with high magnification. But they are very beautiful and play an important role in the food chain. sea ​​life. People, as you know, eat a wide variety of foods, but it all comes down to three factors: water, salt, solar energy. It is thanks to solar energy that all living things on the planet are provided with food, and plants create this food by capturing carbon from the atmosphere or water. They use this element to build their own tissues, creating, as scientists say, primary biomass. It is this biomass, created by plants under the influence of sunlight, that feeds all living things on the planet. You can build a simple, as scientists call it, food chain: plants ~ herbivores ~ predators. Few people eat predators: every organism tries to shorten the food chain, to get closer to the primary creators of food, plants. In the sea, the food chain will be somewhat longer than on land: plants photosynthesize biomass, small marine animals that make up the food of the fry feed on it; Larger fish feed on the fry, and these fish are eaten by, say, cod. And each of us has eaten cod, right? So it turns out that through a series of stages we feed on solar energy, which plants on our planet can capture. We will begin our description of the inhabitants of the seas and oceans with single-celled animals and plants.
12. 24 DISCOVER the world TENANTS OF ALL FLOORS 25 Radiolarians Meet the radiolarians, or rays Foraminifera ki. Their sizes range from 50 microns to 1 mm. They have a skeleton surrounding the central part, which is also surrounded by the thinnest threads with which this tiny creature catches food - even smaller protozoa, tiny algae. Radiolarians form the basis of plankton. Many planktonic rays have inclusions in their bodies in the form of algae, which capture carbon dioxide released by the animal. The rayed flagellate, no more than 2 mm in diameter, receives oxygen for respiration from the algae. They have one peculiarity: when irritated (from excitement, such a combination, to the mutual benefit of different seas, for example), the night light flashes brightly. During the day, organisms are called symbiosis and the spread of arachnylcorus, of course, these outbreaks are invisible, but at night there are thousands of strange things among the inhabitants of sea waters. The radio waves of these little ones begin to glow. This phenomenon is found not only in surface waters, and it occurs in waters, but also at depth, in the Kuril-Kamchatka region, when oars hit the water, when moving in a warm depression, they were found at the bottom - 4 km from but yes, even from splashes. Some nocturnals settle on the surface. on radiolarians and exist in symbiosis with them. Another most abundant tiny inhabitant of the sea Another inhabitant of the sea that has a strong affinity for seawater is foraminifera. mitive structure are sponges. They don't swim. They also have shells. Planktonic forages are free, but are fixed on something solid. The minifera have long shells around them, and these animals can only be seen during research. They provide them with buoyancy. From shells in laboratories, but their skeletons are quite noticeable, these crumbs also consist of sea silt. us. They are found both in the intertidal zone and on the In plankton there is also another inte great depths. resin crumb - nocturnal light. Often its osprey The size of sponge skeletons varies from several can be seen in the Black Sea. These pans are up to 2-2.5 m long, they are colored yellow, green, red and others. bright colors, but there are also whitish, even transparent ones. The surface of the body of sponges is permeated with pores - finely sized holes, into which water and food are absorbed; central part the skeleton has a wider opening for the ejection of undigested particles. Scientists know more than 3,000 species of sponges, divided according to their skeletal composition into calcareous, ordinary and glass. Sponges are immobile animals. They reproduce either by budding, like a branching plant, or sexually: a larva-ball acanthomera emerges from the egg
13. 26 DISCOVER THE WORLD RESIDENTS ON ALL FLOORS 27 seas. A wide belt of sponge settlements was found around Antarctica at a depth of up to 500 m. Calcareous sponges usually prefer shallow water, glass sponges prefer deep water. Sponges often develop in symbiosis with other sea inhabitants. They settle on shells in which hermit crabs live. The crayfish moves, the sponge gets a new feeding area. And the leftovers from his table also fall into the sponge. And she disguises the cancer house. There are crabs that cut off a sponge and, holding it with their back pair of legs, carry it on their back. This is also done for camouflage purposes. Over time, the sponge adheres to the shell. There are also quite outlandish symbioses: a sponge grows to the back of a crab, already sitting on the shell of a hermit crab. So two clawed hands live, connected by a sponge. no more than 2 mm in diameter. For some time, the larva settles in the central channel of the sponges, the shrimp swims, and then attaches to the bottom, where it develops. That's where they reproduce. In Japan it is customary to become an independent individual. give a glass sponge with shrimp for a wedding. Sponges often form continuous thickets at the bottom, inside: these shrimp (necessarily a pair, a male, and himself, for example, in the Sea of ​​Japan. They are found in large numbers) penetrate inside the sponge at the larval stage, off the coast of the Barents Sea. Fishermen try to avoid these places, as sponges clog their nets. The most diverse and colorful sponges are in the tropical Sponges rasnailuya ch-asha Nentmun.a axin.el.la siphon.oha.lin.a sea rossella anelsin.
14. 14. 28 DISCOVER THE WORLD TENANTS OF ALL FLOORS 29 and then they can’t get out and THEY spend their whole lives up to 30 m long, and the bubble itself is in a sponge. rarely exceeds 30 cm. Tentacle Sponges secrete toxic substances that kill; they are usually directed downward, but in small animals, and have bad smell. There are realities: they are sponges when they move, drilling corals, mollusk shells. they reach for the physalia under the top. There is a whole group of “toilet” sponges - their skeletal structure, collecting all living things from the ground, devoid of sharp needles, elastic and soft, still ancient from the upper floor of the ocean. the Greeks used these elastic seafood instead of mo. Some tentacles are flickering, a couple of buds. Fishing for these sponges continues today. Even while licking prey, others participate in plantations of sponges that are specially created: the skeleton of the tua in digestion. The food of physalia alata, sponges are cut and lowered to the bottom, is varied over time - whole sponges grow from diatoms and pieces from pieces. radiolaria to shrimp and fry. Coelenterates are other multicellular fish. organisms living in water. Their body consists of Physalia - inhabitants of the tropic sac, in the cavity of which digestion occurs, and occasionally they are consumed by food, hence the name of the type of these animals. fresh waters. Their venom is similar to that of coelenterates. The sizes of coelenterates range from 2 mm to a cobra - it acts on a nerve of 2 m (not counting the thirty-meter tentacles). Frequently system. Poisonous, they exist in the form of colonies. The overwhelming majority are physalia, discarded species live in the sea from the waves on the shore and even from the top to the deepest dry areas. Physalia is sometimes called physalia. Glass sponges. Each individual animal has the shape of either a lump: its crest is curved into a polyp or a jellyfish. in the form of the Latin letter “8”, which, as it turned out, allows the pheronema to maneuver in the wind like a sail on the border of an airborne ship. Along with the physalia on the surface and aquatic environment floats, drifts and sailboat. This is also a colony of sea life and a beautiful bubble of blue or reddish color. Pu of animals, having a high triangular outgrowth on the air bladder. The oval bubble is filled with gas, similar in composition to the atmospheric disk, reaching 12 cm. Sailboats are usually blue, they are hardly noticeable on the water. Pita mu, and inflated like a balloon. The sailfish is loaded with plankton, and on _ -- - ----- napYCHl< верху шара находится слег­ верхней его стороне путешест­ ка извилистый гребень ­ это физалия. Может пока­ вуют мелкие голубые крабы. На парусниках откладывают икру заться, что это своеобразное животное, но на самом деле некоторые летучие рыбы, а три вида моллюсков питаются ими. это целое сообщество поли­ Одним словом, парусник, в отли­ пов и медуз. Щупальцев у чие от физалии, не защищен. физалии много, достигают
15. 15. 30 DISCOVER THE WORLD RESIDENTS OF ALL FLOORS 31 In all our seas, except in the Black and Azov Seas of the Caspian Sea, you can often find the root-eared jellyfish, or Aurelia. mouth. Its dimensions are up to 40 cm. Its umbrella is flattened, up to in diameter, and the coloring is 40 cm in diameter, pinkish-whitish with a blue-violet border on the upper side. The Cornerot has no tentacles - there are no four darkish circles, but the oral lobes behind the bald spots (gonads) end in eight barks from under the umbrella, like a donkey's ears with dissimilar outgrowths, four protrude (hence the name). Corks have oral lobes. The strong-muscled aurelia feeds on plankton, swims sluggishly, ra, it constantly actively throws out strong waves, swims, squeezing the dome and the mass of these jellyfish onto the shore. The calmer the sea, the closer the aurelia, throwing out from under the umbrella, stays to the surface. Propagates water. Touching it, the cross is aurelia, laying eggs; The larvae float at the bottom causing a severe burn. up to 7 days, then they sit on the bottom like polyps. They feed at shallow depths of the Pacific coast, they are also like polyps, driving water to the mouth of the tentacles, sometimes found in large quantities as crosses. After some time, the milk buds bud. This jellyfish got its name from the cross-shaped jellyfish. different designs, which is clearly visible in the cold waters of our seas, lives similar to its yellowish-brown dome, which has a diameter similar to Aurelia cyanea. Its dome reaches 2 m in diameter up to 30 mm. Touching this jellyfish is very red, in the center it is yellowish, red at the edges. Shchu is dangerous - it first causes burns and chills, then pain in the cyanea's fingers is long (up to several meters), pain in the joints and numbness of the limbs, coughing and breathing in 8 groups, hanging like a net. Stinging sewing. Cells that are especially sensitive to poisonous secretions when touched cause severe pitting of jellyfish eyes. The little cross hunts in a unique way. burn, palpitations. From the depths, the jellyfish quickly moves to the surface; Having reached it, it turns over, spreads numerous tentacles and begins to slowly sink. At depth it turns over again and rushes to the surface. In tropical waters there are many deadly jellyfish (sea wasp, chiropsalmus and others), as well as their larvae, and it is better to stay away from these gelatinous creatures, although in Japan and China they eat jellyfish. If jellyfish swim freely and only their larvae, like those of Aurelia, settle on the ground during development, then in coral polyps the opposite happens:
16. 32 DISCOVER THE WORLD TENANTS OF ALL FLOORS 33 they lead an attached lifestyle, and the larvae of the Mediterranean majority of them are free-swimming. Nicella is usually red, Colonial coral polyps of gorgonians live on small very plant-like ones. Gorgonian colonies are up to 5m deep. This species attaches itself to rocks, rocks, and hard ground, but is successfully kept there and prefers to settle outside the surf zone. Gore marine aquariums. Gonaria are called horn corals. Today, up to 1,200 species of sea feathers have a skeleton known to be up to 1,200 species. They prefer moderately unbranched, consists of warm and tropical waters, in the Arctic there are few of them, all from a soft trunk, from which 30 species are found in Antarctica. Deep-sea horns have “feathers”, or species have the height of the "trees)) - up to 2 m. So that the branches. The trunk - this overgrown colony does not collapse, it also has a thick trunk - the neck body of the primary axial skeleton, resisting the currents. This skeletal, shoots - bud of years has a high concentration iron oxides, which have fallen secondary. To the bottom of which its color ranges from pink to red-black. feathers do not grow, they When the horny substance of gorgonines predominates, the skeleton at the base of the trunk can be white, brown, and black. swollen end, I stick “off the coast of Cuba in the surf zone there is a fan in the soft ground, like Venus with a very strong skeleton up to 2 m in height and an anchor. If necessary 1.5 m wide. The skeleton is flexible and sea feathers can move to another area and fly under the influence of the surf, like a fan. bottom, which is facilitated by a well-developed muscle system. About 300 species of these polyps are known. There are very few of them in the gorgonian polar zones, and almost half of the noble corals known settle in the shallow waters of the tropics. There are, however, deep-sea species that descend to depths of up to 6 km. At night, some of these polyps glow. Most sizes are up to 60 cm, but at the station “ North Pole)) managed to obtain a specimen 260 cm high. The bright red colonies of pennatula, common in the Atlantic and Indian Oceans- its lateral branches look like leaves. When irritated, they begin to glow blue and violet, light waves beautifully run throughout the colony. Sea anemones are also corals, only soft, without a visible skeleton and leading a predominantly solitary life. They are often compared to the amazing flowers of the sea and called sea anemones.
17. 17. 34 DISCOVER THE WORLD TENANTS OF ALL FLOORS 35 Their body is cylindrical, in the axle, it turns into a mucus sole, a secreted lump. The stinging mucus, which immobilizes the stomach cells and attaches itself to hard objects, can also burn your hand. Oral disc of human races. placed on top of the cylinder, Most anemones it is surrounded by tentacles with stinging cells that live in shallow water. some live in the depths. On some tentacles, from 6 to 10 kilometers long, there are swellings where they are scanned. The lifestyle is deeply centered, especially many aquatic species have so far been studied by stinging cells. Eggs weak. The serpentine apemope is widely represented in some sea anemones. Sea anemones are developed in the oceans and live in special Kama waters, but several rakh are inside the mother’s body. The larvae of the species have adapted to low salinity and live, feed, swim for 7-8 days in plankton, and then, for example, in Cherny and even in Azov and Baltic, they settle on the bottom. com seas. They are not always motionless. Movement Anemones feed interestingly - among them there are sea anemones more often at night, and this is done both by predators and by consuming organic materials: by pulling, for example, the sole, suspensions in the water. When they settle on the tentacle of the second and become fixed, they pull up the rest of the body; having bent the edible particles, the cilia drive this piece along, secure it with the tentacles, separate it again to the top, and then the tentacle bends and brings the sole and secures it in a new place; Place it on a piece in your mouth. If the settled piece is inedible, the side, separate the sole and move with pushes of the soles, the cilia nevertheless also drive it to the top, howling forward. And there are also burrowing sea anemones: they move and then the tentacle bends in the other direction, and they do not make wave-like movements like a worm. the edible piece is washed off. Predatory sea anemones Planktonic sea anemones have an air bubble, capture food with their tentacles and bring it to their mouth. on the sole and hang on the surface with tentacles. Their prey is mollusks, crabs, and fish. Hungry ak down. Some sea anemones guard their hunting grounds by sitting motionless on their grounds; they have a special bag of goads, spreading their tentacles wide; which is directed towards the uninvited guest after sensing movement in another sea anemone. If the salvo was fired<<при подхо­ де, она начинает шевелить де», гостья, хоть и ра­ щупальцами, искать добычу. неная (в месте пораже­ Б удержании крупной добы­ ния ткани мертвеют), чи участвуют все щупальца, старается уползти. При с мелкой справляются одно сильном залпе на близ­ или несколько. Сытая акти­ ком расстоянии акти­ ния, а также испуганная, втя­ ния-пришелец может гивает щупальца, съеживает­ погибнуть.
18. 18. 3b DISCOVER THE WORLD TENANTS ON ALL FLOORS 37 Now let’s move on to modrepore corals, the ones that are probably known to everyone. They also have another scientific name - scleroactinia (from the Greek word scleros - “hard”). These are also sea anemones, only very small ones. These small sea anemones are capable of building huge reefs and even islands in the ocean. The coral polyp secretes calcareous threads around its body and gradually becomes surrounded by a mesh. New portions of lime are released onto this mesh in droplets and balls until a solid structure emerges, inside which the polyp itself sits on a special cup. The shapes of the resulting structures are visible in the drawings: bushes, flat lattices, “cauliflower”, and balls. The brain coral creates a structure similar to the human brain. Modrepore corals are found everywhere in the World Ocean and at different depths. But in subpolar and moderately warm waters at depth they are small and inconspicuous. It's a different matter in the tropics - the coral forests there are very impressive. This is facilitated by better conditions for the development of corals, which need oceanic, salty water. Corals can withstand an increase in salinity and a decrease in nitrogen and phosphorus in digestible compounds. It itself leads to their death. There have been cases when polyps are unable to extract these elements from sea water due to their strong ability. The algae, in turn, receives a downpour, which falls on the coral reef due to carbon dioxide from animals and some organic substances during low tide, the corals immediately die. Death of some substances. And in order for this animal-growing ral reef to be an ecological disaster, since numerous corals are dying and numerous body symbioses are working, light is needed to photograph the inhabitants of the reef. The second condition for the well-being of algae synthesis. In addition, the algae inside the polyp is protected from those who want to feast on it. corals - warm water: at 200 C, corals begin to freeze. In the tropical zone, the calcareous skeleton of corals does not freeze. This is one of the reasons why most collapse. Over millions of years, huge corals were formed, they live in tropical waters and do not like depths. The third condition is absolutely clean lime deposits, which are now being successfully developed. Houses are built from the skeletons of corals, port moving (thanks to the surf) water: from turbidity and under jetties, dams. In tropical countries, they are used to pave the streets; when the oxygen levels drop, the corals die. Finally, guys, filters are made FROM them to purify water, they are based on the condition - corals need light. The point is that wood is polished, metal is polished. For these purposes, it is known that algae live in the body of corals. They additionally use only old corals; recently dead ones provide polyps with oxygen, and in addition,
19. 19. RESIDENTS OF ALL FLOORS 39 are not suitable due to the porous structure. But they are also used - to decorate grottoes in parks, to decorate aquariums, and are sold as souvenirs. Among coelenterates, symbiosis with other organisms is widely developed. Often the skeletons of polyps are overgrown with bryozoans, sessile crustaceans. Sometimes large, beautiful ascidians attach themselves to them. Polyps, in turn, often themselves envelop algae - sponges and the same ascidians. And polyps sometimes settle on each other. Yellow gorgonians attract yellow sea anemones with their color. And blue sea anemones settle on brown-blue colonies of another gorgonian. Sea anemones love to travel in underwater “taxis” - they will visit new places and steal some of the food from their horse. Deep sea anemones settle near the mouth opening of holothurians (we will talk about them below). Sea anemones often ride on shells in which mollusks live. Sometimes the mollusk is no longer in the shell - a hermit crab has taken its place. On such shells, sea anemones even change their usual color, acquiring the same color as that of the head and chest of the crayfish. Sea anemone not only feeds on crumbs from the crayfish's meal, but also protects it with its stinging weapons. Corals
20. 40 DISCOVER THE WORLD RESIDENTS OF ALL FLOORS 41 But the Mediterranean crab built its own algae from it. About such a symbiosis to mutual wearing with sea anemones in a different way. We have already talked about the benefits of each claw. At low tide, he collects convoys of sea anemones and, instead of forming large green spots in the sun: the cluster catches prey, puts these sea anemones forward, does not allow the worms to dry out without water, and the algae to darken. They, naturally, grab everything living with their tentacles and intensively photosynthesize. That’s what I want. and paralyze him. And the crab takes the prey and eats it. say that these worms are recharging their batteries. Sea anemones here are assigned the role of a service dog: and fish. Symbiosis with algae determines the distribution of the protector and the provider for the host. The relationship of ciliated worms: they live in the high tide zone. The relationship between sea anemones and fish is also peculiar, but at low tides, in coastal waters. Below 1000 m we will talk about the views of this later. And finally, these worms are not found anywhere. The sea lives around our inverted skyscraper. Other no less interesting worms also live in sea waters. Ciliated worms and worms are not similar animals - thin and long nemerteans. live Some planktonic forms of worms are similar. The length of some species reaches 10-15 m or more. on disks, others have an elongated shape. Many Most, however, do not grow longer than 20 cm. They feed on diatoms, but there are also predators. They live in the coastal zone, under stones, in crevices. Oxypostia, for example, feeds exclusively on them, sometimes in tubes formed by secretions of other ciliated worms (it lives in the distance on the skin. Nemerteans are predators: they are fast in the eastern seas). :K:onwomota has the shape of a candy wrapper, catches prey, grabs it in rings, like a boa constrictor, and for candy, and it lives in the Atlantic Ocean. They hit it with a trunk, at the end of which there is a sharp spike. The sizes of these worms are small, the giant among them, but nemerteans have chemical receptors, with the help of the Pian anaperus, up to 1.2 cm long. The convoy of which the animal receives information about the state lives on algae. Crawling, it leaves behind the external environment and primitive eyes. the plant has sticky mucus, other chalk stick to it. The largest nemerteans are found in benign animals. Stumbling upon such a prisoner, the Kongs of England. Lineus is long - this is his scientific view that runs on him with the front part of the body and according to the name - usually reaches 10-15 m, but it has been found fattening. :K:onwomota has a brownish color: in the body of worms almost 30 m long. The thorn at the end of the trunk is not poisonous, so you have to be careful with them. sea ​​worm nemermuna How beautiful these worms are can be seen in the pictures. The body of annelids is clearly divided into a head, body and anal lobe. The eyes are located, of course, on the head, but they can also be on the body, on the tentacles, on the tail. The body consists of ring segments, on the sides of each segment are parapodia - special outgrowths, organs of movement (parapodia translated from Greek means “like legs”). Parapodia of marine polychaetes are tufts of bristles. Polychaetes are found everywhere in the World Ocean and on all its levels. In the Barents Sea, on one square meter of the bottom, scientists counted 90 thousand polychaetes

About 35 grams of salt, mostly table salt, are dissolved in one liter of sea water. However, in the blood and tissue fluid of most marine fish the concentration of salts is three times lower.

This creates a strong osmotic pressure (that is, the pressure that occurs between solutions of different concentrations when they come into contact). It “sucks” water from the fish’s body. And although its covers prevent the outflow of fluid, a certain amount of water is still lost through the gills, mucus, excrement, etc. To make up for this loss, fish drink sea water and “desalinize” it inside the body, removing excess salts - partly through the intestines, but mainly through the gills.

And even more details...

The so-called Case-Wilmer cells are responsible for this, in the membranes of which there are special proteins that carry salt ions into the external environment. Since this transfer occurs towards seawater (where the salt concentration is higher), it requires energy. In freshwater fish, the same proteins act in the opposite direction, capturing ions from the outside. In migratory fish that move from seas to rivers for spawning or vice versa, these proteins switch from one mode to another.

Osmotic pressure is the force acting on a semipermeable membrane separating two solutions with different concentrations of solutes and directed from the more concentrated to the more dilute solution. Osmotic pressure can be very significant. In a tree, for example, under the influence of osmotic pressure, plant sap rises from the roots to the very top. But in a tree, the movement of a concentrated solution, such as plant sap, is not limited by anything. If such a solution is in a confined space, for example in a blood cell, then osmotic pressure can lead to rupture of the cell wall. It is for this reason that drugs intended for administration into the blood are dissolved in an isotonic solution containing as much sodium chloride (table salt) as necessary to balance the osmotic pressure created by the cellular fluid. If infused drugs were made in water, osmotic pressure, forcing water into the blood cells, would cause them to rupture. If you introduce too concentrated a solution of sodium chloride into the blood, then water will come out of the cells and they will shrink.

The amount of osmotic pressure created by a solution depends on the quantity, and not on the chemical nature of the substances dissolved in it (or ions, if the molecules of the substance dissociate). The greater the concentration of the solution, the greater the osmotic pressure it creates. This rule, called the law of osmotic pressure, is expressed by a simple formula very similar to the ideal gas law.

The law of osmotic pressure can be used to calculate the molecular weight of a given substance.

1. The amount of water that marine fish absorb depends on the degree of salinity. The saltier the water, the more the fish drinks.
2. The gills of fish that live in salt water absorb some salt.
3. By osmosis, fish can pass large amounts of water through their gills.
4. Excess salt is excreted in the urine.
5. Water swallowed by saltwater fish is absorbed by the intestines.

Freshwater fish secrete salt and absorb water through their skin, so they do not need to drink water. The level of salt in the body of freshwater fish is replenished with food and ions (salt) deposited in the gills.

1. Driven by the force of osmosis, water enters the fish's body through the gills.
2. Some of the salt is lost by the gills as a result of osmosis.
3. Freshwater fish have excess water, which they excrete as very dilute urine.

If the fish are swapped

In their usual home, sea fish maintain a normal water-salt balance by drinking large amounts of water and excreting excess salt. In fresh water, saltwater fish absorb water, diluting the liquid environment of their body with it. Unable to retain salt or get rid of excess water, the fish dies. Typically, freshwater fish regulate the salt levels in their body tissues by absorbing salt and excreting water. In salt water, fish lose water that they cannot replace; The salt content in her body rises to lethal levels.

Fickle natures

Several species of fish are diadromous, meaning that they can live in both salt and fresh water, adjusting their body fluids to suit environmental conditions. They drink water - or abstain from it - depending on the salt concentration in their habitat. In addition, their gills and kidneys are able to quickly switch from processing salt water to fresh water, and vice versa. Salmon, which live in the ocean and spawn in rivers, as well as sturgeon, panther and lamprey, which live in river mouths, are also among the easily adaptable fish. Some species of diadromous fish are shown in the illustration above.

sources

Pike belongs to the order of predatory fish. It feeds on perches, minnows and other fish that live in fresh waters. In addition to fish, pike can feed on molting crayfish and their eggs.

That is, pike can become infected from any fish, crayfish or caviar. By eating infected fish, pike becomes a carrier of all kinds of helminths. The probability of pike being infected with worms is 100%.

Classification of pike infestation with helminths:

Unfortunately, many people underestimate, or do not attach importance to, the danger that exists when infected with helminths. An undiagnosed disease in time can not only “present” a bouquet of diseases, but also lead to life-threatening complications, including death.

Once in the human body, for its development and life, the worm takes all the substances it needs. This leads to digestive disorders, hypovitaminosis, loss of proteins, carbohydrates, drop in hemoglobin, decrease in minerals, blockage of blood vessels, bile ducts, etc.

Its waste products cause all kinds of allergic reactions, reduce immunity, negate the effectiveness of vaccinations, lead to destabilization of the entire body as a whole, and lead to complications in the form of cancer.

Let's consider what consequences diseases have for a person who eats river pike fish, usually infected with helminth larvae.

What is the danger of opisthorchiasis

If the disease is not treated, the following consequences are possible:

• the functioning of the gastrointestinal tract is disrupted;
• bronchitis, pneumonia, and asthmatic manifestations often occur;
• arthritis of the joints develops;
• cardiovascular activity is impaired;
• leads to nervous disorders;
• causes liver cancer;
• provokes pancreatic cancer.

Even after complete recovery, which lasts a very long time, irreversible processes remain in the pancreas and liver.

What is the danger of diphyllobothriasis

The broad tapeworm is the largest tapeworm. Its length reaches 10 - 15 meters. It can live in the human body for more than 20 years.

When suffering from diphyllobothriasis:

• the digestive system is affected;
• a severe form of anemia occurs;
• hypovitaminosis develops;
• possible development of atrophy and necrosis of tissues to which the helminth is attached;
• a large accumulation of worms can lead to intestinal obstruction.

An advantage in diagnosing this disease is the presence of segments in human stool that are visible to the naked eye.

Chinese fluke

The Chinese fluke is a type of flatworm. Its length is 10 – 20 mm. Lives in the human body for about 30 years.

The disease clonorchiasis can have the following complications:

• gallstones;
• yellowness of the skin;
• liver abscess;
• cirrhosis of the liver.

When children become ill with clonorchiasis, not only destruction of the child’s internal organs occurs, but developmental delays are also possible.

The trematode Metagonimus yokogawai belongs to the class of flukes. The worm has a length of 2 to 2.5 mm.

When suffering from metagonimiasis, the body becomes completely sensitized. This worm can spontaneously exit the body under the influence of the immune system, but can also lead to the following complications:

• enteritis;
• heart failure;
• granulomatous inflammation
• blockage of blood vessels in the brain.

Do not expose yourself and your family to the risk of these dangerous diseases! Eat only well-cooked pike.

Oriental fluke lanceolate fluke liver fluke Siberian fluke pinworms roundworms head lice lamblia Siberian fluke cat fluke blood flukes bovine and pork tapeworms

Pike caviar contains larvae of the same dangerous diseases as the fish itself. You can become infected with worms if the caviar is poorly processed: not salted enough, not treated with boiling water before salting, or not sufficiently heat treated.

Dried, lightly salted, smoked pike, as a rule, is a source of infection with helminths. Never give it to children!

When eating dried, lightly salted, smoked pike, think about whether the momentary pleasure of eating is worth the treatment of dangerous helminthic diseases.

Do not neglect the information contained in this article. Don't be careless!

👉Opinion of the Ministry of Health of the Russian Federation about the drug

Shark - sea, crucian carp - pond

Surely many of the site visitors wondered why some fish can live only in fresh water, and others only in salt sea water? What difference does it make to these aquatic animals? It turns out that there is a difference, and for many fish it is so significant that if you place them in an alien environment (the sea or, conversely, a river), they will die.
It is curious that the origins of the reasons lie in physics textbooks. The work of all metabolic and excretory processes in the body of fish depends and is adjusted by the so-called osmotic pressure.
What is it?

Osmotic regulation in sharks

Osmosis- the tendency of any solution to decrease the concentration of substances dissolved in it upon contact with a solvent (the base of this solution) through a partition permeable to the solvent. The solvent begins to penetrate into the solution through this very partition, reducing its concentration. This creates a certain pressure called osmotic pressure.
In relation to aquatic animals, for example, fish, osmotic pressure occurs when the internal environment of the fish body (blood, lymph) interacts with the external environment (water) through the skin. Depending on which of these media has more minerals and salts dissolved in it, it can act either as a solvent (giving water to the solution) or as a solution (sucking water out of the solvent).

The explanation may be a little confusing, so let's try to simplify it.
The internal environment of the fish (blood, lymph) is in contact with the external environment (water) through the skin of its body, which allows water to pass through in one direction or another in order to equalize the concentration of dissolved substances in both environments. The process occurs in one direction and is called osmosis. The pressure of water moving from the body of a fish outward (or vice versa - from the external environment into the body) is called osmotic pressure.

Now things are starting to become clearer.
In the case of freshwater fish, their internal environment (blood and lymph) contains more salts and minerals than the external environment - river or lake water, i.e. in this case, the solvent is the external environment, the solution is the internal one. Water is constantly absorbed into the body through the skin of freshwater fish to equalize the concentration of salts outside and inside, in accordance with the above-mentioned laws of physics.
Freshwater fish have to protect the body from excessive watering, leaching of salts and minerals, so nature has provided a protective mechanism for them - efficiently working kidneys. They filter the internal environment, carefully separating from it salts and minerals beneficial to the body, and excess water is removed with urea and other waste products.

Now let's look at this process in the body of a marine fish, for example, a shark.
Her blood and lymph contain less salts than sea water, so a reverse osmotic process takes place here - water is intensively drawn out from the internal environment through the skin. Since water is a vital element for metabolic processes, nature had to provide other protective mechanisms to prevent sharks from dehydration.
The solution was found to be very simple - sharks constantly “drink” sea water, from which the fresh component is absorbed into the blood and lymph through the walls of the stomach. The excretory system of sharks is configured to intensively remove excess salts and minerals through the intestines, gills and with the help of the rectal gland. And water is carefully retained in the body.
It is for this reason that sharks produce very little urine - it contains valuable fresh water.

Osmotic pressure in each species of fish is a relatively constant value and is adjusted to the ratio of the concentration of substances in the internal environment of their body with their preferred habitat.
At the slightest change in this ratio, the excretory system begins to fail. Therefore, if a freshwater fish is placed in sea water, its body will quickly lose water and dehydration will occur with all the ensuing consequences. Freshwater fish do not have mechanisms for removing excess salts from the body, and their concentration in the blood and lymph will exceed the norms permissible for life.
If you place a shark in fresh water, the effect will be the opposite - its internal environment will quickly lose salts and minerals, since the shark does not have protective mechanisms to prevent the loss of these substances from the internal environment and they will be washed out of the blood and lymph into the external environment (fresh water ).

As you can see, the reason that freshwater fish live in fresh water and sea fish live in salt water is due to the functioning of their excretory organs. Some provide for the removal of excess water from the body, while others remove excess salts.

Reading this article, the smartest people are already wondering - what about anadromous, semi-anadromous fish? And what about the famous blunt-nosed shark, capable of living wherever it wants, after all?

It turns out that some fish are “armed” with a universal system of excretory organs. They can automatically restructure their body to function in different environments, with osmotic pressure different in direction. If they get into sea water, their gills and intestines take on the main function of the excretory system, and when they enter rivers and freshwater bodies, the intensive work of the kidneys begins, and the process of removing excess water from the internal environment of the body begins.
Of course, this diagram is somewhat simplified, but the basic principle is as follows.

I hope you now understand why river and lake fish will feel discomfort in the sea, and may even die, and sharks (with the exception of some species) “turn up their nose” at fresh and even brackish water.