DEEP-SEA ANIMALS, inhabitants of the World Ocean at depths from 200 to 11,022 m (Mariana Trench). There are faunas of the slope (bathial), the ocean floor (abyssal) and oceanic trenches (ultra-abyssal, or hadal, with a depth of more than 6000 m). The ocean floor accounts for about 55% of the Earth's surface and is the largest and least studied biotope. Great depths are characterized by high pressure (increases by 1 atmosphere every 10 m), lack of light, low temperature(2-4 °C), lack of food and a bottom covered with thin silty sediment. The main source of nutrients coming from the upper horizons of the water column are flows of organomineral particles and lumps (“sea snow”), as well as the remains of (pelagic) animals living in the water column (“rain of corpses”); in high latitudes, the sedimentation of phytodetritus plays an important role, especially intense during the period of “blooming” of water (in 3-4 days its flow reaches the bottom, forming a continuous layer up to 3 cm thick). The characteristics of the animal world of great depths are determined by living conditions. Thus, the most striking difference between deep-sea animals is the simplification of their organization and the presence of devices for holding on semi-liquid soil (flat body shape, long limbs - stilts, etc.). Among planktonic organisms there are many transparent forms. Bioluminescence is widely used for illumination and lure of prey (angler fish), camouflage, warning, scaring off or distracting predators (shrimp from the genus Acanthephyra and cuttlefish from the genus Netherotheutis release clouds of luminous liquid as a smoke screen), as well as to attract individuals of the opposite sex (barnacle crustaceans, octopuses of the genus Japetella). There is counter-illumination - “illumination” from below, making the organism invisible in dim lighting from above (in squid, shrimp, fish). Many pelagic crustaceans have a red coloration, which performs a protective function, since the visual organs of deep-sea predators do not perceive red color.
Among the large forms living on the bottom, echinoderms, crustaceans, mollusks, polychaete worms. Maximum species diversity (perhaps even greater than in humid tropical forest) are distinguished by small animals (meiobenthos) with a size of 30-500 microns, among which nematodes and crayfish from the order Harpacticoids dominate. For macrobenthos there is an increase species diversity with depth. For example, in the North Atlantic greatest number species of polychaete worms, gastropods and bivalves and cumaceous crayfish occur at a depth of 2000-3000 m.
Below 10,000 m there are foraminifera, scyphoids of the genus Stephanoscyphus, sea anemones of the genus Galatheanthemum, nematodes of the genus Desmoscolex, polychaetes of the subfamily Macellicephalinae, echiurids of the genus Vitjazema, harpacticoids of the genus Bradya, isopods of the genus Macrostylis, amphipods of the genus Hirondella, bivalves of the genus Parayoldiella and Vesicomya, holothurians of the genus Prototrochus. At a depth of 6000-7000 m, long-tailed and lipariform fish live; at a depth of over 8000 m, erroneous fish are noted. Population density per great depths usually small, but aggregations of animals are known, for example, the holothurian Kolga hyalina in the North Atlantic at a depth of 3800 m. Most deep-sea animals settle with the help of larvae: either self-feeding (planktotrophic) or possessing a supply of nutrients (lecithotrophic). Floating high above the bottom (sometimes for kilometers), they are transported by deep-sea currents. Some deep-sea animals have developed viviparity and gestation of young. See also Hydrothermal fauna.
Lit.: Belyaev G.M. Deep-sea oceanic trenches and their fauna. M., 1989; Gage I. D., Tyler R. A. Deep-sea biology: a natural history of organisms at the deep-sea floor. Camb., 1991; Ecosystems of the deep ocean / Ed. R. A. Tyler. Amst.; L., 2003.
Deep sea fish. They live in conditions where life would seem completely impossible. Nevertheless, it is there, but it takes such bizarre forms that it causes not only surprise, but also fear and even horror. Most of these creatures live at depths between 500 and 6,500 meters.
Deep-sea fish withstand enormous water pressure at the bottom of the ocean, and it is such that fish living in the upper layers of water would be crushed. When relatively deep-sea perciformes are lifted, their swim bladder turns outward due to a drop in pressure. First of all, it is he who helps them remain at a constant depth and adapt to the pressure of water on the body. Deep-sea fish constantly pump gas into it to prevent the bubble from collapsing from external pressure. To float, the gas from the swim bladder must be released, otherwise, when the water pressure decreases, it will expand greatly. However, gas is released slowly from the swim bladder.
One of the features of these deep sea fish it is precisely its absence. When they rise up, they die, but without visible changes.
IN deep-sea depressions An unknown species of fish has been discovered in the Atlantic Ocean near Rio de Janeiro, which can be considered a living fossil. Named Hydrolagus matallanasi by Brazilian scientists, this fish, a member of the chimera subspecies, has remained virtually unchanged over the past 150 million years.
.
Along with sharks and rays, chimeras belong to the cartilaginous order, but they are the most primitive and can well be considered living fossils, since their ancestors appeared on Earth 350 million years ago. They were living witnesses to all the cataclysms on the planet and roamed the ocean a hundred million years before the first dinosaurs appeared on Earth."
Fish up to 40 centimeters long live at great depths, in giant depressions up to 700-800 meters deep, so until now they could not be discovered. Her skin is equipped with sensitive nerve endings, with which she detects the slightest movement in absolute darkness. Despite its deep-sea habitat, the chimera is not blind; it has huge eyes.
Blind deep sea fish
Victims of appetite.
The black snapper fish, which lives at depths of 700 meters and below, has adapted to absorb prey that can be 2 times longer and 10 times heavier than itself. This is possible thanks to the highly stretchable stomach of the black crook. 
Sometimes the prey is so large that it begins to decompose before it is digested, and the gases released in this process push the crooked swallow to the surface of the ocean.
The Crookshanks has an amazing ability to frequently swallow living creatures larger than its own size. At the same time, like a mitten, it is pulled over the prey. For example, a 14-centimeter “dinner” fits in the stomach of an 8-centimeter giant.
Super predator depths of the sea.
Bathisaurus sounds like a dinosaur, which is actually not far from the truth. Bathysaurus ferox belongs to the deep-sea lizards that live in the tropical and subtropical seas of the world, at a depth of 600-3,500 m. Its length reaches 50-65 cm. It is considered the deepest-living super predator in the world and everything that comes in its way , is immediately devoured. As soon as the jaws of this devil fish slam shut, the game is over. Even her tongue is lined with razor-sharp fangs. It is hardly possible to look at her face without shuddering, and it is even more difficult for her to find a mate. But this does not bother this formidable underwater inhabitant too much, since it has both male and female genital organs. 
Real deep-sea hunters resemble monstrous creatures frozen in the darkness of the bottom layers with huge teeth and weak muscles. They are passively drawn by slow deep-sea currents, or they simply lie on the bottom. With their weak muscles, they cannot tear pieces out of their prey, so they do it easier - swallow it whole... even if it is larger than the hunter in size. 
This is how anglers hunt - fish with a lonely mouth to which they forgot to attach a body. And this waterfowl head, baring its palisade of teeth, waves in front of itself a tendril with a luminous light at the end.
Anglerfish are small in size, reaching only 20 centimeters in length. The most large species anglerfish, such as Ceraria, reach almost half a meter, others - Melanocete or Borophryna - have an outstanding appearance.
Sometimes anglerfish attack such large fish that an attempt to swallow them sometimes leads to the death of the hunter himself. So, once a 10-centimeter anglerfish was caught, choking on a 40-centimeter longtail. 
There is a refrigerator in the stomach. Alepisaurs are large, up to 2 m long, predatory fish living in the pelagic zone open ocean. Translated from Latin it means “scaleless beast”, a characteristic inhabitant of open ocean waters.
Alepisaurs, fast predators, have interesting feature: food is digested in their intestines, and the stomach contains completely intact prey, captured at various depths. And thanks to this toothy fishing gear, scientists have described many new species. Alepisaurs are potentially capable of self-fertilization: each individual produces eggs and sperm simultaneously. And during spawning, some individuals function as females, while others function as males.
Do you think that this fish monkfish have legs? I hasten to disappoint you. These are not legs at all, but two males that are stuck to the female. The fact is that at great depths and in the complete absence of light it is very difficult to find a partner. Therefore, as soon as a male monkfish finds a female, he immediately bites into her side. This hug will never be broken. Later he fuses with the female’s body and loses everything unnecessary organs, merges with her circulatory system and becomes only a source of sperm.
This is a fish with a transparent head. For what? At depth, as we know, there is very little light. The fish has developed defense mechanism, her eyes are located in the center of her head so that they cannot be injured. In order to see, evolution has awarded this fish with a transparent head. The two green spheres are the eyes. 
Smallmouth macropinna belongs to a group of deep-sea fish that have developed a unique anatomical structure in order to fit your lifestyle. These fish are extremely fragile, and specimens of the fish that have been collected by fishermen and researchers are deformed due to pressure changes.
Most unique characteristic this fish is its soft, transparent head and barrel-shaped eyes. Being usually fixed in an upward direction with green "lens caps" for filtration sunlight, the eyes of the Smallmouth macropinna can rotate and extend.
In fact, what appear to be eyes are sensory organs. The real eyes are located under the forehead.
One-legged crawling
Norwegian scientists from the Institute of Marine Research in Bergen reported the discovery of an unknown creature living at a depth of about 2000 meters. This is a very brightly colored creature crawling along the bottom. Its length is no more than 30 centimeters. The creature has only one front "paw" (or something very similar to a paw) and a tail, and at the same time does not look like any of the sea creatures known to scientists.
10994 meters. Bottom Mariana Trench. There is a complete absence of light, water pressure is 1072 times higher than the surface pressure, 1 ton 74 kilograms presses per 1 square centimeter.
Hellish conditions. But there is life even here. For example, at the very bottom they found small fish up to 30 centimeters long, similar to flounder.
One of the deepest-sea fish is the Bassogigus.
Scary teeth of the underwater world 
The large-headed daggertooth is a large (up to 1.5 m long), not numerous inhabitant of medium depths of 500-2200 m, presumably found at depths of up to 4100 m, although its juveniles rise to a depth of 20 m. Widely distributed in subtropical and temperate regions Pacific Ocean, V summer months it penetrates as far north as the Bering Sea. 
The elongated, serpentine body and large head with huge beak-shaped jaws make the appearance of this fish so unique that it is difficult to confuse it with anyone else. Characteristic feature external structure The daggertooth is its huge mouth - the length of the jaws is about three-quarters of the length of the head. Moreover, the size and shape of the teeth on different jaws of the daggertooth differ significantly: on the upper ones they are powerful, saber-shaped, reaching 16 mm in large specimens; on the bottom - small, subulate, directed backward and not exceeding 5–6 mm.
And these creatures are like something out of a horror movie about aliens. This is what polychaete worms look like under high magnification. 
Another strange inhabitant depths - Drop fish.
This fish lives off the coast of Australia and Tasmania at a depth of about 800 m. Given the depth of water in which it swims, the blob fish does not have a swim bladder like most fish, as it is not very effective under high water pressure. Her skin is made of a gelatinous mass that is slightly denser than water, which allows her to float above the ocean floor without any hassle. The fish grows up to 30 cm in length, feeding mainly sea urchins and shellfish that swim by.
Even though this fish is inedible, it is often caught along with other prey such as lobsters and crabs, putting it at risk of extinction.
Distinctive external characteristic fish drops is her unhappy expression.
The piggy squid is just an outlet in the world of deep sea monsters. So cute. 
And in conclusion - a video about deep sea creatures.
Ocean abysses are one of the most mysterious and little-studied places in the world. There are many strange and unusual creatures, most of which are unlike anyone else. Many explorers of the depths also agree with the statement that the most scary creatures worldwide.
Pike blenny (lat. Neoclinus blanchardi)
The name of this fish is not the most intimidating, nor is its appearance. But as soon as you provoke her, she will immediately open her mouth and turn into a terrible monster, ready to swallow prey many times larger than herself. N. blanchardi, naturally, is not able to swallow a large enemy, opening its mouth wide and showing its toothed mouth, the fish only strives to protect its territory. It turns out that she does this quite effectively, sometimes in this way she manages to drive away even very large aggressors.
live blennies mainly off the Pacific coast of North America.
Coelacanth (lat. Latimeria)
A true living fossil, the only species in the order of prehistoric coelacanth fishes that has survived to this day. Coelacanths appeared on Earth approximately 400 million years ago and have remained virtually unchanged since then. The modern population living in the Indian Ocean near south coast Africa, is estimated at only 300-400 individuals.
Toadfish (lat. Opsanus tau)
Predatory fish from the batrach family. Lives in the western part of the Atlantic Ocean. Leads sedentary lifestyle life. Most spends time hiding in the silt or sand at the bottom of the ocean - this is how the toad fish hunts, waiting for the prey to swim up to it; and sleeps, safely hidden from enemies.
Body covered poisonous thorns, which pose a considerable danger to humans.
Produces very loud sounds, reaching over 100 dB in the immediate vicinity. Thus, the toad fish warn: this territory is mine!
Striped catfish (lat. Anarhichas lupus)
A fish that lives primarily in the cold, deep-sea regions of the Atlantic. Due to its aggressive nature, it received the nickname “Atlantic wolf”.
The teeth of A. Lupus wear out very quickly, probably due to heavy load, but new ones quickly grow in place of the worn ones.
Lumpy carpet shark (lat. Sutorectus tentaculatus)
One of the smallest sharks, the average body length is 72 cm, the maximum is 92 cm.
Lives off the southeast coast of Australia. They are found on rocky reefs and kelp-covered areas where they can ambush prey. They move slowly along the bottom, practically merging with it, which is greatly facilitated by the flattened shape of the body and camouflage coloring.
European anglerfish (lat. Lophius piscatorius)
Quite a large fish with a body length of up to 2 meters. The species is popularly known as "monkfish".
The body is not covered with fish, the skin is dense with numerous outgrowths, bumps and hairs that imitate algae and camouflage the fish.
It hunts using a special bioluminescent bait, hiding at the bottom. The huge mouth and pharynx allow the European anglerfish to swallow very large prey whole.
The monkfish has a nasty character; attacks on larger fish and even divers are not uncommon.
European stargazer (lat. Uranoscopus scaber)
Predatory fish from the order Perciformes. Body size 20-35 cm. Lives in warm regions oceans and the Mediterranean Sea.
The stargazer got its name because of the location of its eyes, which are constantly directed to the sky.
It is dangerous due to the poisonous spines located above the pectoral fins.
Common chauliod (Chauliodus sloani)
A real monster from the abyss. It is found in temperate and tropical zones of the Atlantic, Indian and Pacific Oceans at depths from 500 to 4000 meters.
Due to their narrow, elongated body and huge teeth, they received the nickname “viper fish”. The body length is small: up to 35 cm, while the teeth reach 5 cm in length, which is why the mouth never closes.
The mouth can open 110 degrees, thanks to which the hauliod is able to swallow prey up to 63% of the size of the predator itself.
West Atlantic pipistrelle (lat. Ogcocephalus parvus)
Very strange and yet little-studied fish from the order Anglerfishes. Inhabits the bottom of warm subtropical and tropical seas.
The fins of the pipistrelle bat act more like legs; with their help, the fish slowly moves along the bottom.
Our planet is filled with different living creatures that decorate the Earth and contribute to the ecosystem. But it's no secret that water depths also teeming with many inhabitants. Although the variety of these creatures is not as abundant as on the surface, these organisms are still very unusual and interesting. So, who lives at the bottom of the ocean, what are their living conditions?
Conditions at depth
From space, our planet looks like a blue pearl. This is because the area of all the waters is almost three times larger than the land. Like the land, the surface of the oceans has uneven surfaces. It is dotted with hills, depressions, plains, mountains and even volcanoes. They are all at different depths. Thus, the abyssal plains are submerged at approximately 4000-6000 m. But even there there is life, although this may be surprising, since at a depth of 1000 m the pressure is 100 atmospheres. And with every hundred meters it increases by 10 units. Also, light does not penetrate there, which is why darkness always reigns at the bottom, therefore, the process of photosynthesis does not occur. In addition, under such thickness the water is unable to warm up; in the deepest places the temperature remains at zero. Such conditions make life in these places not very rich compared to the surface, since the lower you go, the less vegetation grows. So the question arises: how do those who live on the ocean floor adapt?
Life of the deep sea
Although it may seem that in such circumstances life is very difficult and even impossible, the local inhabitants are still quite adapted to these conditions. Animals that are at the very bottom do not feel strong pressure and at the same time do not suffer from a lack of oxygen. Also, those who live at the bottom of the ocean are able to feed themselves. Basically, they collect residues that “fall” from the upper layers.
Dwellers of the Deep
Of course, at the bottom the diversity of life is not as great as on the surface of the waters, and count deep sea inhabitants You can do it on your fingers. Unicellular organisms are found here, there are a little more than 120 species. There are also crustaceans, there are about 110 varieties of them. The rest are much smaller, the number of each species does not exceed 70. These few inhabitants include worms, coelenterates, mollusks, sponges and echinoderms. There are also fish that live on the ocean floor, but here the diversity of their species is very small.
Is it really pitch dark there?
Since the rays of the sun are unable to penetrate the abyss of water, there is an opinion that all the inhabitants are in constant darkness. But in reality, many of the animals found there have the ability to emit light. Most of the people who live on the ocean floor have this property: predators. For example, the conical periphylla, emitting light, attracts small inhabitants. This is a trap for them, as they become victims of this predator. But harmless living creatures can also create a glow.
Some fish have certain areas of their body that emit light. More often they are located under the eyes or stretch along the body. Certain species of crustaceans or fish use their vision, but the majority of the inhabitants do not have eyes or have undeveloped organs. This is not surprising, since such “live” lighting, which is created by bottom creatures, is not enough to make the underwater space visible. To get food you have to use your sense of touch. For this purpose, there are modified fins, tentacles or long legs of those who live on the ocean floor. The photo above illustrates one of these unusual creatures, known as the Atoll jellyfish. But in the deep-sea abyss, many living inhabitants lead a mostly motionless life, and therefore resemble flowers and plants.
Loading...
