Life on planet Earth originated in the ocean. It was from the water that the first animals came to land. The inhabitants of the seas and oceans are distinguished by enormous species diversity. All marine representatives of the organic world live in the water column and on the ocean floor. Scientists count more than 150 thousand inhabitants of the oceans and seas, including plant and animal organisms that inhabit the sea and ocean spaces of the planet.
Inhabitants of the seas and oceans: diversity and living conditions
Everyone knows that the aquatic environment is strikingly different from the land-air environment. Significant depths are excommunicated by low temperature and high pressure. The inhabitants of the seas and oceans, living at great depths, practically do not see sunlight, but despite this variety of life forms, it is amazing.
Almost all useful substances that are necessary for the life of the inhabitants of the deep sea dissolve in water. The water space warms up very slowly, but heat transfer occurs over a long period of time. Of course, at significant depths the temperature changes almost imperceptibly.
An important component for all creatures in the water column is the presence of oxygen. In the absence of free oxygen, hydrogen sulfide is formed, this is typical for the Black Sea and Arabian.
For full development, the inhabitants of the seas and oceans need protein, which is found in large quantities in
Flora of the oceans and seas
Sea plants contain chlorophyll, a green pigment. With its help, the energy of the sun is accumulated. Water is split into oxygen and hydrogen, and then the hydrogen enters into a chemical reaction with carbon dioxide from the surrounding aquatic environment. After this, starch, sugar and proteins are formed.
At relatively shallow depths there is a rich flora. The inhabitants of the depths of the sea find their food in these “sea meadows”.
One of the most common algae is kelp; their length can reach six meters. It is from this plant that iodine is obtained, and they are also used as fertilizer for fields.
Another of the brightest inhabitants of the seas and oceans (mainly southern latitudes) are marine organisms, which are called - But they should not be confused with plants, these are real animals. They live in large colonies, attaching themselves to rocky surfaces.
Plants need sunlight, so plants are found at least 200 meters deep. Below only live the inhabitants of the seas and oceans who do not need the light of the sun.
Sea animals
Previously, it was believed that no one lives below six kilometers of depth due to the high pressure that the water column exerts on living beings. But scientists conducted deep-sea studies that confirmed the hypothesis that at great depths there are various species (crustaceans, worms, etc.).
Some deep-sea inhabitants of the seas and oceans periodically rise to depths of up to a thousand meters. They do not float higher, because... Closer to the surface, large differences in water temperature are observed.
Many deep-sea inhabitants who spend their entire lives at the bottom have no vision. But some parts of their body have special flashlights. They are needed to escape predators and to attract potential prey.
Animals of the seas and oceans feel comfortable in their environment, many of them do not need to adapt to seasonal environmental changes.
Octopus is the most intelligent representative of cephalopods
A special role in the life of many marine inhabitants is played by single-celled organisms, which are called plankton and move with the help of currents. They feed on many fish, which constantly follow them. With increasing depth, the amount of plankton decreases sharply.
Scientists have long proven that the inhabitants of the seas and oceans live in all water layers. These animals and plants are distinguished by great species diversity, as well as unusual shapes and colors. You can endlessly admire the various species of fish, corals and other marine inhabitants of the most bizarre forms that seem to be aliens from another planet and admire the perfection of nature.
In conclusion, I bring to your attention an extremely interesting documentary film dedicated to various inhabitants of the seas and oceans entitled “The Most Dangerous Animals. Depths of the sea." Take a look, it will be interesting!
And in more detail, these articles will introduce you to interesting representatives of the underwater world:
The Pacific Ocean is the largest ocean in the world and covers about a third of the Earth's surface area. The depth of the ocean varies from shallow shores to the Mariana Trench, the deepest point of which (Challenger Deep) reaches a depth of almost 11 thousand km. Due to its sheer size, the Pacific Ocean is home to countless species of sea creatures, and some of the most famous animals are:
Penguins
The Pacific Ocean is home to numerous species, including Galapagos penguins, Humboldt penguins, Magellanic penguins, crested penguins, and yellow-eyed penguins. These animals vary in size, from 1 kg in weight and a height at the withers of about 40 cm, to a weight of 35 kg and a height of about 100 cm.
Dugong
Elephant seals
The largest genus distributed in the Pacific Ocean. It includes two species: the northern elephant seal and the southern elephant seal. The northern species is distributed in the northern part of the Pacific Ocean along the North American coast, and the southern one is found near. These enormous marine mammals exhibit sexual dimorphism, with adult males being much larger than females. The average weight of an adult elephant seal is about 2 tons, with some individuals growing up to 4 tons.
Manti
The largest stingrays, representatives of the Manta genus, live in the northern part of the Pacific Ocean. They are found near coral reefs, where they hunt fish and tiny fish. Adult manta rays can have a body width of up to 9 m and a weight of 3 tons. The stingray is a solitary animal and surprisingly calm, despite its impressive size. Stingrays are hunted by large sharks and killer whales.
Sea otters
The sea otter is a common inhabitant of the North Pacific Ocean, especially on its northern and eastern coasts. Sea otters are relatively small in size compared to other marine mammals, and adults can reach a maximum weight of about 45 kg and a body length of up to 1.5 m. They feed on small marine animals and seaweed.
sea turtles
Sea turtles are a general term used to describe seven species in the order turtles. These species include: flathead sea turtle, green turtle, hawksbill turtle, Atlantic ridley turtle, leatherback turtle, loggerhead turtle and olive turtle. The leatherback turtle is the largest of all sea turtles, with adults weighing up to 700 kg. Sea turtles are found in tropical areas of the Pacific Ocean.
Sea slugs
Sea slugs are the term used to refer to marine species known as nudibranchs, as well as several gastropods that closely resemble terrestrial slugs. Sea slugs are primarily found in coral reefs and come in a variety of shapes and sizes, but most are partially translucent. Most sea slugs have feather-like structures on their backs that act as gills. Sea slugs are carnivores and they prey on fish, anemones, and planktonic organisms.
Octopuses
It is one of the most common cephalopods in the Pacific Ocean. Different species live in different parts of the ocean. The octopus has one of the largest brain-to-body ratios of any species, and also possesses a complex nervous system. Octopus species vary in size, with the largest being the giant octopus, which can grow up to 50 kg.
Giant squid
The giant squid is a member of the architeutid family ( Architeuthidae). This squid is one of the most elusive Pacific creatures and one of the largest invertebrates in the world (the other being the large Antarctic giant squid). Adults grow up to 13 m in length, and females are relatively larger than males. Giant squids are found in the North Pacific Ocean near Japan.
Pacific white-sided dolphins
Pacific white-sided dolphin - found in the North Pacific Ocean. Animals of this species have a gray back and a creamy white belly and neck. Adult females grow up to 100 kg and have a body length of about 2.2 m, and males weigh up to 180 kg and are 2.3 m long. These dolphins are quite mobile and become victims only of killer whales.
Sea lions
The sea lion is the largest member of the eared seal family ( Otariidae). Adult males can reach a weight of 1000 kg and a body length of 3-3.5 m. This species exhibits sexual dimorphism, and males are larger than females. Males have a massive neck covered with a lion-like mane. These marine mammals are found in the North Pacific Ocean.
Hammerhead sharks
The hammerhead shark is one of the most common sea creatures in the Pacific Ocean. These sharks are easily identified by their head shape, which resembles a hammer. Thanks to this feature, the shark has 360-degree vision. Adult sharks can reach a mass of more than 500 kg and a body length of about 6 m.
In the depths of the sea and ocean there are a huge number of all kinds of creatures that amaze with their sophisticated defense mechanisms, ability to adapt, and, of course, their appearance. This is a whole universe that has not yet been fully explored. In this rating, we have collected the most unusual representatives of the depths, from beautifully colored fish to creepy monsters.
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Our rating of the most unusual inhabitants of the depths opens with the dangerous and at the same time amazing lion fish, also known as the striped lionfish or zebra fish. This cute creature, about 30 centimeters long, spends most of its time among the corals in a motionless state, and only from time to time swims from one place to another. Thanks to its beautiful and unusual coloring, as well as long fan-shaped pectoral and dorsal fins, this fish attracts the attention of both people and marine life.
However, behind the beauty of the color and shape of its fins are hidden sharp and poisonous needles, with which it protects itself from enemies. The lion fish itself does not attack first, but if a person accidentally touches it or steps on it, then one injection from such a needle will sharply worsen his health. If there are several injections, then the person will need outside help to swim to the shore, as the pain can become unbearable and lead to loss of consciousness.
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This is a small marine bony fish of the pipefish family of the order Pipefish. Seahorses lead a sedentary lifestyle; they attach their flexible tails to stems, and thanks to numerous spines, outgrowths on the body and iridescent colors, they completely blend into the background. This is how they protect themselves from predators and camouflage themselves while hunting for food. Skates feed on small crustaceans and shrimp. The tubular stigma acts like a pipette - the prey is drawn into the mouth along with water.
The body of seahorses in water is located unconventionally for fish - vertically or diagonally. The reason for this is the relatively large swim bladder, most of which is located in the upper part of the seahorse's body. The difference between seahorses and other species is that their offspring are carried by the male. On its abdomen it has a special brood chamber in the form of a sac, which plays the role of a uterus. Seahorses are very fertile animals, and the number of embryos borne in a male’s pouch ranges from 2 to several thousand. Childbirth for a male is often painful and can result in death.
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This representative of the depths is a relative of the previous participant in the rating - the seahorse. The leafy sea dragon, rag-eater or sea pegasus is an unusual fish, so named for its fantastic appearance - translucent delicate greenish fins cover its body and constantly sway with the movement of the water. Although these processes look like fins, they do not take part in swimming, but serve only for camouflage. The length of this creature reaches 35 centimeters, and it lives in only one place - off the southern coast of Australia. The rag picker swims slowly, its maximum speed is up to 150 m/h. Just like seahorses, the offspring are carried by males in a special pouch formed during spawning along the lower surface of the tail. The female lays eggs in this pouch and all care of the offspring falls on the father.
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The frilled shark is a species of shark that looks much more like a strange sea snake or eel. Since the Jurassic period, the frilled predator has not changed at all over millions of years of existence. It got its name from the presence of a brown formation on its body, which resembles a cape. It is also called the corrugated shark due to the numerous folds of skin on its body. Such peculiar folds on its skin, according to scientists, are a reserve of body volume to accommodate large prey in the stomach.
After all, the frilled shark swallows its prey mainly whole, since the needle-like tips of its teeth curved inside the mouth are not capable of crushing and grinding food. The frilled shark lives in the bottom layer of water in all oceans except the Arctic Ocean, at a depth of 400-1200 meters; it is a typical deep-sea predator. The frilled shark can reach 2 meters in length, but the usual sizes are smaller - 1.5 meters for females and 1.3 meters for males. This species lays eggs: the female gives birth to 3-12 young. Gestation of embryos can last up to two years.
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This type of crustacean from the infraorder of crabs is one of the largest representatives of arthropods: large individuals reach 20 kilograms, 45 centimeters in carapace length and 4 m in the span of the first pair of legs. It lives mainly in the Pacific Ocean off the coast of Japan at a depth of 50 to 300 meters. It feeds on shellfish and leftovers and is believed to live up to 100 years. The survival rate among the larvae is very small, so females spawn more than 1.5 million of them. During the process of evolution, the front two legs turned into large claws that can reach a length of 40 centimeters. Despite such a formidable weapon, the Japanese spider crab is non-aggressive and has a calm character. It is even used in aquariums as an ornamental animal.
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These large deep-sea crayfish can grow more than 50 cm in length. The largest recorded specimen weighed 1.7 kilograms and was 76 centimeters long. Their body is covered with hard plates that are softly connected to each other. This armor design provides good mobility, so giant isopods can curl up into a ball when they sense danger. Rigid plates reliably protect the crayfish’s body from deep-sea predators. Quite often they are found in Blackpool, England, and they are not uncommon in other places on the planet. These animals live at depths from 170 to 2,500 m. Most of the entire population prefers to be kept at a depth of 360-750 meters.
They prefer to live on the clay bottom alone. Isopods are carnivorous and can hunt for slow prey on the bottom - sea cucumbers, sponges, and possibly small fish. They also do not disdain carrion, which sinks to the seabed from the surface. Since there is not always enough food at such great depths, and finding it in pitch darkness is not an easy task, isopods have adapted to do without food for a long time. It is known for sure that cancer is capable of fasting for 8 weeks in a row.
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The purple tremoctopus or blanket octopus is a very unusual octopus. Although, octopuses are generally strange creatures - they have three hearts, poisonous saliva, the ability to change the color and texture of their skin, and their tentacles are able to perform certain actions without instructions from the brain. However, the purple tremoctopus is the strangest of them all. For starters, we can say that the female is 40,000 times heavier than the male! The male is only 2.4 centimeters long and lives almost like plankton, while the female reaches 2 m in length. When the female is frightened, she can expand the cape-like membrane located between the tentacles, which visually increases her size and makes her look even more dangerous. It is also interesting that the blanket octopus is immune to the venom of the Portuguese man-of-war jellyfish; Moreover, the clever octopus sometimes tears off the jellyfish's tentacles and uses them as weapons.
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The blobfish is a deep-sea bottom-dwelling marine fish of the psycholute family, which, due to its unattractive appearance, is often called one of the most terrible fish on the planet. These fish supposedly live at depths of 600-1200 m off the coast of Australia and Tasmania, where fishermen have recently begun to increasingly bring them to the surface, which is why this species of fish is endangered. The blobfish consists of a gelatinous mass with a density slightly less than the density of water itself. This allows the blobfish to swim at such depths without expending large quantities.
Lack of muscles is not a problem for this fish. She swallows almost everything edible that floats in front of her, lazily opening her mouth. It feeds mainly on mollusks and crustaceans. Even though the blobfish is not edible, it is endangered. Fishermen, in turn, sell this fish as a souvenir. Blobfish populations are recovering slowly. It takes 4.5 to 14 years for the blobfish population to double.
7 Sea urchin
Sea urchins are very ancient animals of the echinoderm class that inhabited the Earth already 500 million years ago. Currently, about 940 modern species of sea urchins are known. The body size of a sea urchin varies from 2 to 30 centimeters and is covered with rows of calcareous plates that form a dense shell. Based on body shape, sea urchins are divided into regular and irregular. Regular hedgehogs have an almost round body shape. Irregular hedgehogs have a flattened body shape, and the anterior and posterior ends of the body are distinguishable. Spines of various lengths are movably connected to the shell of sea urchins. The length ranges from 2 millimeters to 30 centimeters. Spines often serve sea urchins for movement, nutrition, and protection.
Some species that are distributed mainly in tropical and subtropical regions of the Indian, Pacific and Atlantic oceans have poisonous needles. Sea urchins are bottom crawling or burrowing animals that typically live at depths of about 7 meters and are widespread on coral reefs. Sometimes some individuals can crawl onto. Correct sea urchins prefer rocky surfaces; incorrect - soft and sandy soil. Hedgehogs reach sexual maturity in the third year of life, and live about 10-15 years, up to a maximum of 35.
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Largemouth lives in the Pacific, Atlantic and Indian oceans at depths from 500 to 3000 meters. The body of the largemouth is long and narrow, in appearance it resembles an eel 60 cm, sometimes up to 1 meter. Due to the giant stretching mouth, reminiscent of the beak bag of a pelican, it has a second name - pelican fish. The length of the mouth is almost 1/3 of the total length of the body, the rest is a thin body, turning into a tail filament, at the end of which there is a luminous organ. The largemouth does not have scales, a swim bladder, ribs, an anal fin or a full-fledged bone skeleton.
Their skeleton consists of several deformed bones and light cartilage. Therefore, these fish are quite light. They have a tiny skull and small eyes. Due to poorly developed fins, these fish cannot swim quickly. Due to the size of its mouth, this fish is capable of swallowing prey that is larger than itself. The swallowed victim ends up in the stomach, which can stretch to enormous sizes. The pelican fish feeds on other deep-sea fish and crustaceans that can be found at such depths.
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The sac-eater or black eater is a deep-sea representative of perciformes from the suborder chiasmodidae, living at depths from 700 to 3000 meters. This fish grows up to 30 centimeters in length and is found throughout tropical and subtropical waters. This fish got its name from its ability to swallow prey several times its size. This is possible due to the very elastic stomach and the absence of ribs. A bagworm can easily swallow fish 4 times longer and 10 times heavier than its body.
This fish has very large jaws, and on each of them the front three teeth form sharp fangs, with which it holds the victim when it pushes it into its stomach. As the prey decomposes, a lot of gas is released inside the bagworm's stomach, which brings the fish to the surface, where some black gobblers have been found with swollen bellies. It is not possible to observe the animal in its natural habitat, so very little is known about its life.
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This lizard-headed creature belongs to the deep-sea lizard-heads that live in the tropical and subtropical seas of the world, at depths from 600 to 3500 meters. Its length reaches 50-65 centimeters. Outwardly, it is very reminiscent of long-extinct dinosaurs in a reduced form. It is considered the deepest sea predator, devouring everything that comes in its way. Bathysaurus even has teeth on its tongue. At such a depth, it is quite difficult for this predator to find a mate, but this is not a problem for it, since the bathysaurus is a hermaphrodite, that is, it has both male and female sexual characteristics.
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The smallmouth macropinna, or barrel eye, is a species of deep-sea fish, the only representative of the genus macropinna, which belongs to the order Smeltfish. These amazing fish have a transparent head through which they can watch their prey with their tubular eyes. It was discovered in 1939, and lives at a depth of 500 to 800 meters, and therefore has not been well studied. Fish in their normal habitat are usually motionless, or move slowly in a horizontal position.
Previously, the principle of operation of the eyes was not clear, since the fish’s olfactory organs are located above the mouth, and the eyes are located inside the transparent head and can only look up. The green color of the eyes of this fish is caused by the presence of a specific yellow pigment in them. It is believed that this pigment provides special filtering of light coming from above and reduces its brightness, which allows the fish to distinguish the bioluminescence of potential prey.
In 2009, scientists found that thanks to the special structure of the eye muscles, these fish are able to move their cylindrical eyes from the vertical position in which they are usually located, to the horizontal position when they are directed forward. In this case, the mouth is in the field of view, which provides an opportunity to capture prey. Zooplankton of various sizes, including small cnidarians and crustaceans, as well as siphonophore tentacles along with cnidocytes were found in the macropinna vein. Taking this into account, we can come to the conclusion that the continuous transparent membrane above the eyes of this species evolved evolutionarily as a way of protecting cnidarians from cnidocytes.
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The first place in our ranking of the most unusual inhabitants of the depths was taken by a deep-sea monster called an anglerfish or devil fish. These scary and unusual fish live at great depths, from 1500 to 3000 meters. They are characterized by a spherical, laterally flattened body shape and the presence of a “fishing rod” in females. The skin is black or dark brown, naked; in several species it is covered with transformed scales - spines and plaques; ventral fins are absent. There are 11 known families, including almost 120 species.
The anglerfish is a predatory sea fish. A special growth on its back helps it hunt other inhabitants of the underwater world - one feather from the dorsal fin separated from the others during evolution, and a transparent sac formed at its end. In this sac, which is actually a gland with liquid, surprisingly, there are bacteria. They may or may not glow, obeying their master in this matter. The anglerfish regulates the luminosity of bacteria by dilating or constricting blood vessels. Some members of the anglerfish family adapt even more sophisticatedly, acquiring a folding fishing rod or growing one right in their mouth, while others have glowing teeth.
Many scientists believe that the first living creatures evolved in the sea. Hundreds of millions of years passed before animals appeared on land. Life in the ocean is much more diverse than on land, and many types of plants and animals are found only in the seas. The oceans are home to more than 150 thousand species of animals and plants. The weight of all living organisms inhabiting the World Ocean reaches 50-60 billion tons. In the waters of the ocean there are all types of the organic world - from the simplest organisms to mammals.
Only centipedes, spiders and amphibians do not live in the sea.
The aquatic environment differs from the air: the temperature is distributed differently in it; at great depths there is enormous water pressure; sunlight penetrates only into the uppermost layers.
Among the many remarkable properties of water that are important for the organisms living in it, low thermal conductivity, very high heat capacity and high solubility of various substances in water are especially significant. Due to the high heat capacity of water, the temperature regime of the oceans does not change as sharply as on land. This is important for both cold-blooded and warm-blooded animals. Aquatic organisms do not need adaptations to sudden changes in environmental temperature.
Slowly heating up, the water of the oceans also slowly releases heat into the atmosphere. Therefore, the warmest water in the oceans and seas occurs when the hot summer period on land has already ended. Ocean water stores enormous reserves of heat. Giving it to the air, it significantly affects the climate of surrounding countries. The average temperature of the surface layer of water in the World Ocean is +17°.4, and the surface layer of air on the surface of the entire globe is only +14°.4.
Daily fluctuations in water temperature off the coast, in small bays and bays are greater than in the open sea. Seasonal changes in water temperature are more significant in temperate regions of the northern and southern hemispheres. But seasonal differences in temperature are observed in the upper layer - up to a depth of 500 m. At greater depths, over 1000 m, the temperature changes very little throughout the year.
In addition to water temperature, the most important condition for life is the presence of oxygen. Marine organisms breathe oxygen, just like their terrestrial “relatives”. In gases dissolved in water, oxygen averages 35% (in an oxygen atmosphere 21%). The oxygen that animals and plants breathe comes into the water from the atmosphere or is formed as a result of photosynthesis of algae, so there is more of it in the surface layers than in the deep ones. Sea currents mix the water well, and oxygen in small quantities spreads to the bottom of the oceans. In places where mixing of deep waters is difficult, such as in the Black and Arabian Seas, the Bay of Bengal, at depths of over 200 m there is no free oxygen, hydrogen sulfide is formed there.
In addition to gases, ocean waters contain significant amounts of various dissolved substances. The salinity of sea water and the composition of salts are of great importance for the development of the organic world. On average, ocean waters contain 35 G of salts per 1 kg of water. If all the water in the oceans were evaporated, their bottom would be covered with a 60-meter layer of salt.
To develop, living organisms need substances from which proteins are formed. The primary creators of organic matter in the sea, as well as on land, are plants. All marine animals obtain protein in ready-made form by eating algae or eating animals.
Marine plants - algae, like sushi plants, contain a green pigment - chlorophyll. It helps them use the energy of sunlight to create a chemical process inside the cell, as a result of which water captured by plants is first decomposed into hydrogen and oxygen, and then the hydrogen is combined with carbon dioxide absorbed from the surrounding water. This is how carbohydrates are formed: glucose (sugar), starch, etc. Then, in the body of the algae, due to the combination of carbohydrates with phosphorus, nitrogenous and other substances absorbed from water, protein and other organic substances are formed. Oxygen released during the decomposition of water is released from the cell. It enriches water with gas necessary for the respiration of organisms.
In the surface layers of water and shallow coastal areas of the seas and oceans, rich vegetation develops - a variety of algae. A huge number of crustaceans, worms and other small animals “graze” in such “underwater” meadows.
Laminaria are large seaweeds reaching 6 m in length. Many kelp are edible: they contain sugary substances. Iodine is extracted from these algae. Kelp is also used to fertilize fields (photo taken at low tide). Photo: Chris Booth
The larvae of many benthic animals also rise here to fatten, and as adults they firmly adhere to the bottom or burrow into the silt. Small animals serve as food for herring, sardines and other commercial fish, as well as whales. Inhabitants of great depths are filter feeders or predators. Filters filter large quantities of water to filter out food - plant and animal debris that comes from the surface layers of the water.
Continental waters wash away various substances from the surface of the land and “fertilize” the oceans. In addition, dying organisms, falling to the bottom of the ocean and decomposing there, serve as a rich source of replenishing water with reserves of nitrogen, phosphorus, potassium and other substances necessary for plants. Currents, mixing the water in the sea, carry these substances upward and “fertilize” with them the layer of water where marine plants live, with the help of which these substances again enter the cycle of life.
Sea molluscs, corals, most sponges, sea urchins and stars, worms, bryozoans, and some algae (lithothamnia)
Underwater corals are very similar to highly branching algae, but they are not plants, but animals. They attach one end to underwater rocks and form large colonies. Photo: Derek Keats
They extract huge amounts of calcium from the water, which is used to build shells, shells and various skeletons. Radiolarians, silicon sponges and some other animals need silicon. We can say that all substances dissolved in water, even in minute quantities, are necessary for the inhabitants of the seas and oceans. The remarkable constancy of the salt composition of ocean water is maintained by the activity of organisms.
Plants need sunlight to live normally. The sun's rays do not penetrate to great depths of the sea. This is explained primarily by the fact that some of the sun's rays are reflected from the surface of the water. The lower the sun is above the horizon, the greater the percentage of rays reflected from the sea surface, so in the Arctic seas light penetrates to a shallower depth than in equatorial waters.
In water, different parts of the solar spectrum penetrate to different depths. Red and orange rays are quickly absorbed by the first meters of water, green ones disappear at a depth of 500 m, and only blue ones penetrate up to 1500 m. Algae especially need red and orange rays and to a lesser extent green ones. Therefore, plants in the sea are found mainly at a depth of up to 100, less often up to 200 m. Animals, as a rule, do not directly need light and inhabit ocean waters to maximum depths.
The entire multi-kilometer layer of ocean waters can be divided into two “floors”: the upper one - producing organic matter and the lower one (deeper than 200 m) - consuming.
Until recently, it was believed that ocean depths of more than 6 km were lifeless, since supposedly no living organism could withstand the enormous water pressure.
Soviet scientists have proven that even at the greatest depths there are fish, crabs, crayfish, worms, mollusks and other animals. Deep-sea inhabitants have adapted to life under high pressure. The body of marine animals contains a large amount of water, and it compresses very little, so the pressure inside the body easily balances the pressure from outside. This is why life at great depths was possible.
The starfish searches for food with the help of numerous legs-papillae located on the underside of the rays. This animal is a predator; it attacks prey that is larger than itself. In such cases, the starfish turns out its stomach and envelops the victim with it, and then retracts the stomach again. Photo: Ryan Poplin
Many inhabitants of great depths rise to the surface layers. They can often be found at a depth of 1000 and occasionally 500 m. The high water temperature prevents the animal from rising higher: after all, they are accustomed to living at constantly low temperatures. Water at great depths has a temperature of only plus 1-2°. Under such conditions, all life processes are delayed. Organisms grow much slower than in the warm surface layers of the ocean. The reason for this is the small amount of food.
Animals of the depths are in constant darkness, many of them are blind, and some have eyes that have a “telescopic” structure that allows them to catch the slightest glimpses of light. Some animals have special “lanterns” that glow in different colors. So, for example, on the head of the small costus fish, one pair of light organs emits red light, and the other pair emits green light. Some mollusks have light organs that emit blue light. There are animals in which a special luminous liquid accumulates in their bodies. At the moment of danger, the animal releases it and blinds the enemy.
Many deep-sea creatures have various organs that help them perceive sound waves. After all, in pitch darkness you need to be able to catch the movement of a far-swimming enemy or, conversely, determine the location of the desired prey. Sound travels well in water - almost 5 times faster than in air (about 1520 m/sec).
The size of the mouth and the abundance of teeth are striking in deep-sea fish. Some fish's jaws are designed in such a way that they can move wide apart, like those of snakes, and a small predator is able to swallow a prey even larger than itself. This is due to the small number of living creatures at great depths: if you are lucky enough to catch prey, then you need to swallow it whole. As you can see, organisms living at great depths have adapted well to the conditions of their environment.
The closer to the surface, the richer and more diverse life becomes. Of the 150 thousand species of marine organisms, more than 100 thousand species live in the upper layers (up to 500 m depth).
Living conditions at sea are very favorable. In the sea, plants are surrounded on all sides by a nutrient solution, and on land they extract water and nutrients dissolved in it from the soil with their roots.
To stay on the ground, living things need strong roots or strong limbs. On land, the largest animal is the elephant, and in the sea - the whale, which is 20-25 times heavier than the elephant. Such a huge animal on land would not be able to move and would die. Another thing is in the water. As is known, any body located in water is subject to a buoyant force equal to the weight of the liquid in the volume of the immersed part of the body. That is why a whale, with its enormous weight, has to expend many times less effort when moving in water than it would require on land.
Swimming jellyfish. It captures prey with its long tentacles. Photo: Luca Vanzella
Temperatures at sea are more constant than on land. Marine animals do not need to seek protection from the cold in winter and from the heat in summer. With the onset of frost, a thick layer of ice and snow prevents the cold from penetrating into the water. Ice, like a fur coat, covers the reservoir and protects the water from freezing. Even in the cold Arctic, the sea never freezes to the bottom. The temperature in winter in the depths of the sea, under the cover of ice, is almost the same as in summer.
Life in the depths of the ocean
Favorable living conditions contributed to the development of the greatest diversity of organisms in the sea. All inhabitants of the seas, according to the conditions of their existence, are divided into three groups: plankton, nekton and benthos.
Plankton includes various microscopic algae (diatoms, peridinea, blue-greens), unicellular animals (globigerina, radiolarians, etc.), small crustaceans, jellyfish, some worms, eggs and fry of many fish. The word “plankton” is Greek and means “wandering”, “carried”. Indeed, all these sea inhabitants are passively transported by the movement of water. They actively move mainly vertically - up or down. During the day, plankton animals descend into the depths, and in the evening they rise to the surface layers. The plankton is followed by fish that feed on it. Currents carry plankton over considerable distances, and planktivorous marine animals find food everywhere.
No matter how small planktonic organisms are in volume, their number in the seas and oceans is enormous. If we could put all the whales and fish on one side of the scale, and plankton on the other, it would overwhelm. The amount of plankton decreases sharply with depth.
Nekton includes: most fish, pinnipeds (seals and walruses), cetaceans (whales, sperm whales), cephalopods, sea snakes and turtles. Nekton is also a Greek word and means “floating.” Animals that belong to nekton have a streamlined body shape that helps them move quickly in the water. It is not easy even for a fast-moving vessel to catch up with a whale, and it is difficult for fast-swimming fish to escape from the mouths of dolphins.
Most fish and mammals make long journeys - migrations. With the onset of spawning time, many fish unite into schools of millions, sometimes occupying an area of several tens of kilometers. Traveling from the feeding area to the spawning areas (spawning), fish swim hundreds and thousands of kilometers.
Many fish go from the sea to rivers to spawn. These fish are called anadromous, in contrast to sea fish. Migratory fish, especially salmon and sturgeon, travel long distances up rivers. If the path in the river is blocked by rapids, the fish jump out of the water and overcome them with strong jumps.
The valuable commercial fish nelma (salmon) emerging from the Arctic Ocean into the rivers of Siberia travels more than 3 thousand km up the river to its spawning site. The fish movement is especially majestic in the rivers of the Far East, when millions of schools of pink salmon and chum salmon rush into the rivers of the Bering and Okhotsk Seas. They do not feed in rivers and die after spawning.
A different type of migration is observed in the eel. Adult eels travel from rivers to the ocean to spawn. European eels spawn in the waters of the Sargasso Sea. To do this, they cover a distance of 7-8 thousand km. After spawning, adult eels die, and the larvae are transported to the shores of Europe by the Atlantic current.
The White Sea herd of harp seals makes long journeys. In the summer they fatten in the waters surrounding Spitsbergen and Franz Josef Land, and in the winter they come to give birth to their young in the throat of the White Sea.
Whales travel almost 5 thousand km to the warm part of the ocean, where their calves are born. Together with the young whales, the parents go back to the cool waters to the north and south to fatten.
Among cetaceans, a distinction is made between baleen and toothed whales. The first got their name because rows of horny plates hang from their palate, covered with horny fibers along the inner edge, like a mustache. Passing large amounts of water through their mouths, baleen whales strain and swallow small inhabitants of the surface layers of the ocean.
The sea anemone and the mollusk live in “friendship”: the mollusk carries the sea anemone, and it protects its “driver” from enemies with stinging capsules that can stun even small fish. Photo: Tanaka
Toothed whales hunt for fish and squid, and killer whales (predatory dolphins) hunt for seals, fur seals, and walruses. Everyone's surprise, even in the picture, is a sperm whale with a huge, seemingly bluntly chopped off head. His body is huge, weighing 20 tons - almost as much as his entire body. Sperm whales are excellent divers. Their main food is cephalopods. Sperm whales dive to a depth of several hundred meters for large squid. Scars from the suckers of giant squid (more than 10 m long) are often visible on the skin of sperm whales. Whales have become so adapted to life in water that they have acquired a variety of body shapes. Previously, the whale was called fish-whale. Whales cannot go onto land.
Whales are mammals. They give birth and feed their young with milk in the water. Whales breathe atmospheric air and therefore live in the surface layer of ocean water. In the process of evolution, a peculiar distribution of hunting sites occurred between whales. Baleen whales fish the upper layers - up to 50 m; Close relatives of sperm whales, bottlenose whales, dive deeper, up to 100 m, and even deeper, up to 300 m, sperm whales hunt for food. Baleen whales stay underwater for 10 minutes, and sperm whales stay underwater for up to 45 minutes.
Fish, seals, whales and many other representatives of nekton are the main prey of marine fisheries.
All inhabitants of the bottom of the seas and oceans belong to the benthos. The word "benthos" is Greek and means "deep". For benthic animals, hard ground is needed as a permanent support, for example for corals, or temporary, as for flounder. Some representatives of benthos settle on coastal rocks and beaches above the water level, where only splashes of waves reach.
Algae attached to the seabed and many animals that live in the tidal zone live in the air for hours at low tide. However, this does not hinder their development.
Various large algae grow to a depth of 100 m. Deeper down they are already disappearing. The sun's rays are quickly absorbed in water, so bottom algae cannot live at great depths.
The amount of benthos decreases with depth. At depths of up to 300 m, there are about 250 g of benthos per 1 m 2 of the bottom, and near the shore and in shallow waters it amounts to many kilograms. At a depth of more than 10 thousand m, there are less than 1 G of benthic animals per 1 m 2.
The world's oceans are divided into five biogeographic regions: Arctic, Antarctic, North and South temperate regions and Tropical region.
The Arctic and Antarctic regions are characterized by low, often even negative water temperatures in winter and summer and floating ice.
In the temperate regions of both hemispheres, water temperatures vary significantly between seasons; in the Tropical region - constantly high temperature of the surface layers of water. Seasonal temperature fluctuations here rarely exceed 2°.
Life in the northern seas
Let's start from the north. Ice fields stretch before us, but they are not lifeless. A polar bear is creeping up to the edge of the ice floe. There are seals lying on the ice floe. Their limbs, or flippers, look like oars. At the ends of the toes of the hind limbs, cartilaginous plates are developed, and between the toes there are swimming membranes, increasing the area of the “oar”. The soles of the hind limbs are adjacent to each other, and the animal can bend them to the right and left, like the tail of a fish. On land, seals move with difficulty, crawling on their bellies. Other pinnipeds - walruses, sea lions and seals - although they move with the help of their limbs along the shore or ice, they also “crawl” rather than “walk”.
The body of an adult seal is covered with short, coarse hair. Under the skin there is a thick layer of fat; it, like a warm fur coat, prevents the animal from chilling in cold water.
Pinnipeds feed mainly on fish and crustaceans. Seals, like all pinnipeds, have an excellent sense of smell and hearing, and their eyes see well both under water and on land. That is why a polar bear that sneaks up on a seal on the ice often leaves without a meal: the seal disappears into the hole with lightning speed.
A flock of unicorns (often called narwhals) frolics in a large ice hole. This is a type of dolphin. The thick skin of a unicorn is covered with a stratum corneum. It, like armor, protects the animal from bruises on the ice. The only tooth of the males grew in length and turned into a tusk. Occasionally they have two tusks. Unicorns feed on fish, especially cod. Unicorns are often found in the waters surrounding Greenland, Franz Josef Land and Severnaya Zemlya.
Near the Siberian coast our ship will meet another species of dolphin - the beluga whale. A herd of beluga whales came here to feed on navaga, goby, Pechora herring and salmon fish. The skin of beluga whales has “armor”. Beluga whales got their name from the white skin color characteristic of adult animals. In the north they are called "belugas". During the course, beluga whales roar abruptly. This roar is reminiscent of the roar of a bull and at the same time the grunt of a walrus. This is where the famous expression comes from: “Roars like a beluga.” Beluga whales eat a lot of pink salmon and chum salmon.
Herds of harp seals can be found in the Barents Sea. More than a hundred years ago, bowhead whales lived here. Now they are rare: almost all of them have been exterminated. The waters of the Barents Sea are populated by millions of crustaceans and large quantities of fish - herring, cod, haddock.
A baby harbor seal is a squirrel. Photo: Brian Scantlebury
Now let's go south. We will find ourselves in the northern part of the Atlantic Ocean, which belongs to the North Temperate Region. Here we will meet many different fishing vessels. They went fishing for Atlantic herring, cod, haddock, sea bass, and flounder. The sardine fishery is developed near the southern border of the Northern Temperate Region.
Soon flying fish, inhabitants of the Tropical region, will begin to fall onto the deck of our ship. In flying fish, the fins have turned into wings. But the wing of a fish is not the wing of a bird, but of a glider. The flying fish does not flap its wings, but flies like a glider, spreading its fins wide.
It is impossible to list all the inhabitants of the Tropical Region. Warm waters of the World
The oceans are abundantly populated by a variety of animal and plant species. 860 species of brown, red and green algae grow off the tropical shores of the Malay Archipelago. There is no such abundance of vegetation in any sea. There are also 40 thousand species of various marine animals - sponges, corals, worms, mollusks, fish. Corals form islands and reefs. The famous Great Barrier Reef to the east of Australia stretches for 2200 km, the Barrier Reef of New Caledonia - for 1500 km.
Among the coral colonies, fish of bizarre shapes, motley, like butterflies, flash. Here is a strange ball covered with needles: this is a hedgehog fish. When she sees an enemy, her body swells.
Dense mangroves are sometimes found at river mouths and in the swampy lowlands of tropical coasts. Many marine animals live among the roots of mangrove trees, including jumping fish. These fish crawl out of the water onto the shore and hunt for insects. Some species of jumpers have become so adapted to living without water that they die if they are deprived of the opportunity to be in the air.
Shark. On its belly there are sticky fish that travel with the shark as “free passengers” and eat up any leftover food after it. Photo: ba.zinga
On the shore you can see a crab called the coconut or palm thief. It has almost said goodbye to water and comes to the sea only to reproduce. The crab feeds on the pulp of coconuts, after which it climbs onto a palm tree. It cuts the nuts with its powerful claws, throws them down and eats them.
In tropical seas live giant stingrays - relatives of sharks - with greatly overgrown lateral fins. Electric stingrays are interesting - Torpedo. They have special organs in their bodies that store electrical energy. The discharge of electricity from a stingray is sufficient to paralyze a fish or drive away a predator.
Among the sharks there are giants - whale sharks - up to 20 m in length. The life of peculiar fish - pilot fish and stickfish - is closely connected with sharks. A pilot fish helps a shark locate a school of fish. Sticky fish are attached to the shark’s belly with a special suction cup and thus travel with it. The stickers and pilots eat up the remaining food of the shark.
Among marine mammals, dugongs and manatees from the order Sirenidae are interesting. These are marine herbivores. Their forelimbs have turned into flippers, but their hind limbs are missing. They live in a zone of lush development of bottom algae.
Continuing our journey south, we find ourselves in the Southern Temperate Region. Here you will meet old acquaintances from the northern seas: whales, seals, sardines, sea bass, mullet. On secluded islands you can see seals. They are close relatives of our Far Eastern seals.
Penguins live in the high latitudes of the southern hemisphere. They live on islands, shores and even the ice of Antarctica. You can also find seals here. Whales swim near the edge of the ice. Among them there are blue whales, reaching 33 m in length and 120 tons in weight. One such giant weighs as much as 25 elephants or 200 bulls. The life of whales is spent at sea. A “baby” whale receives 100-200 liters of milk per day from its mother. A whale can stay underwater for 5-10 minutes. Having emerged to the surface, he forcefully exhales the exhaust air. The steam exhaled with air condenses in the cold and a fountain is formed. You can recognize the type of whale by the shape of the fountain.
The Antarctic seas are now the main whaling area. Whale fat, skin, and meat are used, and medications are obtained from the endocrine glands. In Antarctica you can find huge floating factories of the Soviet whaling fleet.
In the northern temperate region of the Pacific Ocean and in our Far Eastern seas there live many species of animals close to the inhabitants of Atlantic waters: cod, herring, sardine, Kamchatka salmon, etc. You can also see here animals that have not been seen before. Amazing number and diversity of salmon
fish: pink salmon, chum salmon, chinook salmon, sockeye salmon. On the coasts there are large rookeries of sea lions and fur seals. Sea otters (sea otters) are found on the Commander and Kuril Islands. They are also called Kamchatka or sea beavers. This name is unfortunate, since the beaver belongs to the order of rodents and feeds on plant foods. The temperate region of the Pacific Ocean is richer in a variety of animal species than the same region in the Atlantic Ocean.
Layers in the ocean
When the bathyscaphe "Trieste" sank to the bottom of the deepest depression in the World Ocean - Mariana (11,022 m), it stopped three times, encountering some invisible obstacle. As is known, in a bathyscaphe gasoline plays the same role as hydrogen or helium in an airship. To continue the submersion of the submersible, it was necessary to release a certain amount of gasoline, this made the device heavier. What prevented the submersible from descending?
An obstacle on the way was a sharp increase in the density of water. In the ocean, with depth, as a rule, the temperature decreases and the salinity of water increases, as a result of which its density increases. At some depths, all these changes occur abruptly. The layer in which there is a sharp change in temperature and density of water is called the “jump layer”. There are usually one or two such layers in the ocean. Trieste discovered a third one. Upon careful examination of the water in the Pacific Ocean, it turned out that in some areas it had increased radioactivity due to the explosions carried out by the United States at that time.
The ocean is a large body of water. Today, there are four oceans located between the continents, which combine with each other, are connected to the atmosphere and are in constant motion. Oceans occupy approximately 3/4 of the planet's surface. All oceans are home to a huge number of plants and animals - from microscopic plankton to whales reaching tens of meters in length. Ocean life forms have different characteristics depending on the temperature and depth of the water layer in which they live and their food sources. Scientists have discovered many species only recently. Even today, most of the oceans are still unexplored.
Inhabitants of the Arctic Ocean
Compared to other oceans, the fauna of this smallest ocean is very poor. Among the large marine mammals you can find beluga whales, narwhals, various cetaceans, including the rare bowhead whale. And also several types of seals: bearded seal, elephant seal, harp and leopard seal, ringed seal.
Belukha- a five-meter toothed whale. In the summer, these amazing white animals feed on fish and crustaceans near the seabed under the ocean ice cap.
Narwhal- the most northern species of all toothed cetaceans. The only representative of the genus and a close relative of beluga whales. The dimensions are large: the body is up to 6 m long, weight - 1-1.5 tons. Spends the entire year in this region, unlike other whales that migrate south for the winter. Winters in an ice hole among ice floes. They feed on fish, shrimp and squid. The female gives birth to one baby. In males and very rarely in females, one curled tusk, up to three meters long, develops in the left upper jaw. The narwhal has no other teeth. Hence the second name of this animal – unicorn.
bowhead whale- a large dark whale that feeds on zooplankton. Zooplankton are tiny animals that feed on phytoplankton (microscopic plants). These include fish larvae and tiny relatives of shrimp and crabs, the copepods.
The cold waters of this ocean are home to an amazing jellyfish - the giant cyanide, as well as a unique ice fish.
Cyanea, Arctic Cyanea or Lion's Mane- the largest jellyfish in the world. It grows tentacles more than 50 m long, and its “umbrella” reaches a diameter of 2 m. Surprisingly, this large jellyfish as an adult exists only for one summer season. In the spring, young jellyfish appear, grow quickly, reaching gigantic sizes at the end of summer, and die in the fall. They feed on zooplankton, including small fish.
Ice fish- translucent small fish. Thanks to natural “antifreeze”, the blood of this fish does not freeze even in ice.
Inhabitants of the Indian Ocean
The fauna of the Indian Ocean is amazing and very diverse. Among the animals, one can distinguish a large number of crabs and an interesting fish - the mudskipper, which inhabits almost all the mangroves (a form of coastal vegetation) of the ocean.
Mudskippers- these are fish no more than 20 cm that deftly jump along the shore and climb the roots and brushwood of mangroves. Here they hunt insects and small crabs. They can jump up to 30 cm, or even higher. Thanks to excellent vision and dexterity, they grab flies on the fly. They also have a unique ability for fish to look at any object with both eyes at the same time. On land they breathe through moist, mucus-covered skin. They can stay out of water for a long time. It is enough for them to plunge into at least some puddle from time to time. In addition, they often sit on land for a long time, dipping their tail into the water. Despite well-developed gills, they quickly die if they are forcibly kept in deep water.
We can talk at length and in detail about sharks that live in the waters of the Indian Ocean. There are a lot of them here. Mako shark‒ the fastest shark in the world, it can reach speeds of up to 50 km/h. It has a powerful, streamlined body of deep blue color, and can reach up to 4 m in length. Great blue shark‒ a four-meter shark with a dark blue back and white belly.
But the main owner of these waters, undoubtedly, is the white shark or, as it is sometimes called, carcharodon. Great white shark‒ a six-meter shark with a gray back and white belly. It mainly feeds on seals and fur seals, but sometimes attacks people. Between 50 and 70 shark attacks on humans are recorded annually. Fewer than 4 attacks each year result in death.
Birds are represented by albatross and frigatebirds. Albatross- a large seabird that in some places can not return to land. Albatrosses catch squid, octopuses and fish from the surface of the ocean. The wandering albatross and royal albatross have a wingspan of up to 3.5 m - they are the largest birds on earth. Frigates- large black and white seabirds. During the mating season, the throat sacs of males turn red, and they inflate these sacs to attract the attention of females. Sometimes frigate birds steal food from other birds, biting others by the tail and forcing them to release the prey, which they pick up and eat.
Residents of the Atlantic Ocean
The fauna of the Atlantic Ocean is very numerous and diverse. Thousands of animal species are found in all areas of the ocean. Here you can see predators dangerous to humans: sharks, barracudas and moray eels.
Barracuda‒ a two-meter fish that hunts in coral reefs, with sharp lower jaw teeth located both inside and outside. They hunt in packs. Moray- a three-meter conger eel that hides in the crevices of a coral reef and from this shelter attacks prey - fish or octopuses.
The world of corals here is also quite unique, and off the coast of Cuba there are entire “underwater forests” - thickets of soft corals. A coral reef is an underwater limestone structure made up of the hard skeletons of tiny animals called polyps. Coral reefs lie in warm, clear, shallow waters near rocky coastlines or volcanic islands. Life flourishes next to them. Many small animals feed on the algae that grows on the corals. The corals themselves provide food for some animals, such as the parrotfish and the crown of thorns star. Just 200 years ago, coral was considered a plant, not an animal. Many coral reefs are under threat of destruction. Water pollution, increases in average temperature, hunting for souvenirs and deepening of fairways for shipping - all this destroys corals that have been growing for millions of years.
The deep ocean is home to sponges, annelids, crustaceans, starfish and crinoids.
Sponge- an invertebrate animal without a heart, brain or developed body parts. Sponges are attached to hard surfaces. They feed by passing and filtering water through small pores of their bodies.
Worms- a group of long, thin, soft-bodied animals. Some species live in burrows or sand.
Crustaceans– arthropods, such as crabs, lobsters, krill and barnacles, which have two sensory receptors on their heads called antennae.
Starfish- an echinoderm with five legs and a mouth on the underside of the body. Uses suction cups on its feet to open shells and eat shellfish. If a starfish loses several limbs as a result of attack by other animals, they then grow back.
sea lilies- graceful creatures that look like flowers belong to the kingdom of fauna. They are divided into two large groups: stemmed and stemless. Stem lilies are attached to one place all their lives. Most often found in the deepest areas. Stemless lilies can not only crawl from place to place, but can even swim slowly, using their tentacles like oars.
Pacific people
More than half of the living matter of the entire Earth's oceans is concentrated in the waters of the Pacific Ocean. The most widespread representative of toothed whales is the sperm whale, and of the toothless whales there are several species of striped whales. The sperm whale is a large toothed whale that can reach 20 m in length. Able to hold his breath for an hour. Dives to depths of up to 3 km in search of giant squid. The giant squid is a type of squid that can grow up to 13 m long. It feeds on fish that live on the seabed. It can live at depths of 200 to 1000 m, so very little is known about this species.
minke whales‒ flexible and fast baleen whales with pronounced grooves on the lower jaw and belly. These include the largest animal on the planet – the blue whale. Which can reach more than 30 m in length. It feeds on huge amounts of krill. Krill- the collective name for small marine planktonic crustaceans (crustaceans), which constitute a significant part of the diet of many animals. At night, huge numbers of krill rise to the surface to feed, where they become food for whales and seabirds.
The northern waters of the Pacific Ocean are home to the now very rare sea lion seal and the walrus, which has a circumpolar range but is now on the verge of extinction. Walruses- large mammals with two long tusks and powerful fins. A layer of subcutaneous fat protects them from the cold. They swim and dive beautifully, and feel the seabed with their antennae in search of crabs and shellfish. Males use their tusks when fighting for a female.
The Pacific Ocean, due to the high temperatures of its surface waters in tropical latitudes, is especially rich in various types of corals, including those with a calcareous skeleton. Coral- hard calcareous material from the skeletons of a colony of polyps. Different types of polyps form corals of different shapes. Polyps- tiny animals whose body consists of a stomach, mouth and tentacles. The soft body is protected by the skeleton. When the polyp dies, it becomes a solid, dead part of the coral, and a new polyp grows in its place. Corals can look like plant branches, tubes, or even a human brain.
A large number of fish are permanent inhabitants of coral reefs. Butterflyfish are small, brightly colored fish, often with eye-like markings near the tail. This coloring allows them to deceive the predator, which attacks the fish from behind, giving it a chance to escape. They feed on small crustaceans and coral polyps. The clownfish is a small, orange-and-white striped fish that lives between the poisonous tentacles of sea anemones. The fish themselves are protected from poison by a layer of mucus, but predators can be burned to death by the poison. Anemones are marine organisms that look like flowers. Relatives of jellyfish and polyps. They attach themselves to rocks and stones and use their tentacles to catch prey. Parrotfish are brightly colored fish with a hard beak. They use this beak to scrape algae from the coral reef, often biting off pieces of coral. Parrotfish have horny plates in their mouths, which they use to crush coral and get to their prey.
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