What does plankton look like in the sea? Interesting facts about plankton. Zooplankton and food chains

plankton

Dictionary of medical terms

plankton (Greek planktos wandering)

a collection of animals and plant organisms, inhabiting the water column and passively transported by the current; characterizes the pollution of a reservoir.

Explanatory dictionary of the Russian language. D.N. Ushakov

plankton

plankton, m. (from the Greek plagktos - wandering) (biol.). Plant and animal organisms that live in seas and rivers and move only by the force of water flow. Plant plankton. Animal plankton. The Papaninites discovered plankton at the most northern latitudes at the pole.

Explanatory dictionary of the Russian language. S.I.Ozhegov, N.Yu.Shvedova.

plankton

A, m. (special). A collection of animal and plant organisms living in the water column and carried by the force of the current.

adj. planktonic, oh, oh.

New explanatory dictionary of the Russian language, T. F. Efremova.

plankton

m. An accumulation of the smallest plant and animal organisms living in seas, rivers, lakes and moving almost exclusively by the force of water flow.

Encyclopedic Dictionary, 1998

plankton

PLANKTON (from the Greek planktos - wandering) is a set of organisms that live in the water column and are unable to resist being carried by the current. Plankton consists of many bacteria, diatoms and some other algae (phytoplankton), protozoa, some coelenterates, mollusks, crustaceans, tunicates, eggs and larvae of fish, and the larvae of many invertebrate animals (zooplankton). Plankton, directly or through intermediate links in food chains, serves as food for all other animals living in water bodies. also Pelagic organisms.

Plankton

(from the Greek planktós ≈ wandering), a set of organisms that inhabit the water column of continental and marine reservoirs and are not able to resist transport by currents. P. includes both plants—phytoplankton (including bacterioplankton) and animals—zooplankton. P. is contrasted with the population of the bottom, benthos, and actively swimming animals, nekton. Unlike the latter, P.'s organisms are not capable of independent movement or their mobility is limited. In fresh waters, a distinction is made between lake limnoplankton and river potamoplankton.

Plant photosynthetic planktonic organisms require sunlight and inhabit surface waters, mainly to a depth of 50-100 m. Bacteria and zooplankton inhabit the entire water column up to maximum depths. Marine phytoplankton consists mainly of diatoms, peridines and coccolithophores; in fresh waters - from diatoms, blue-green algae and some groups of green algae. In freshwater zooplankton, the most abundant copepods and cladocerans and rotifers; in the marine ≈ dominated by crustaceans (mainly copepods, as well as mysids, euphausia, shrimp, etc.), numerous protozoans (radiolaria, foraminifera, ciliates tintinnids), coelenterates (jellyfish, siphonophores, ctenophores), pteropods, tunicates (appendiculars, salps) , barrelworms, pyrosomes), eggs and larvae of fish, larvae of various invertebrates, including many benthic ones. The species diversity of P. is greatest in tropical waters ocean.

The sizes of P. organisms range from several microns to several m. Therefore, they usually distinguish: nannoplankton (bacteria, the smallest unicellular algae), microplankton (most algae, protozoa, rotifers, many larvae), mesoplankton (copepods and cladocerans, and other smaller animals). 1 cm), macroplankton (many mysids, shrimp, jellyfish and other relatively large animals) and megaloplankton, which includes a few of the largest planktonic animals (for example, the Venus belt ctenophore up to 1.5 m long, the cyanea jellyfish with a diameter of up to 2 m with tentacles up to 30 m, colonies of pyrosomes up to 30 m long and more than 1 m in diameter, etc.). However, the boundaries of these size groups are not generally accepted. Many P. organisms have developed adaptations that make it easier to float in water: reducing the specific mass of the body (gas and fat inclusions, water saturation and gelatinous tissue, thinning and porosity of the skeleton) and increasing its specific surface area (complex, often highly branched outgrowths, flattened body). .

Phytoplankton organisms are the main producers of organic matter in water bodies, on which most aquatic animals exist. In shallow coastal parts of reservoirs, organic matter is also produced by bottom plants - phytobenthos. The abundance of phytoplankton in different parts of water bodies depends on the amount in the surface layers necessary for it nutrients. The limiting factors in this regard are mainly phosphates, nitrogen compounds, and for some organisms (diatoms, silica flagellates) and silicon compounds. Over the long history of the ocean, these substances accumulated in large quantities in its depths, mainly as a result of the decomposition and mineralization of organic particles settling from upper layers. Therefore, abundant development of phytoplankton occurs in areas of rising deep waters (for example, at the junction of the warm waters of the Gulf Stream and northern cold currents, in the zone of equatorial divergence of waters, in areas of downward winds near the coast, etc.). Since small planktonic animals feed on phytoplankton and serve as food for larger ones, areas greatest development phytoplankton are characterized by an abundance of zooplankton and nekton. Significantly smaller and only local significance in enrichment surface waters river runoff provides nutrients. The development of phytoplankton also depends on the intensity of light, which in cold and temperate waters determines seasonality in the development of phytoplankton. In winter, despite the abundance of nutrients carried into the surface layers as a result of winter mixing of waters, there is little phytoplankton due to lack of light. Spring begins fast development phyto-, and then zooplankton. As phytoplankton uses nutrients, as well as due to its consumption by animals, the amount of phytoplankton decreases again. In the tropics, the composition and quantity of P. are more or less constant throughout the year. The abundant development of phytoplankton leads to the so-called. blooming of water, changing its color and reducing transparency. When some peridiniums bloom, toxic substances are released into the water, which can cause mass death planktonic and nektonic animals.

P.'s biomass varies in different bodies of water and their regions, as well as in different seasons. In the surface layer of the ocean, the biomass of phytoplankton usually ranges from several mg to several g/m3, zooplankton (meso-plankton) ≈ from tens of mg to 1 g/m3 or more. With depth, P. becomes less diverse and its quantity quickly decreases. In the World Ocean, poor water areas predominate in area over rich ones. The poorest of all is the central tropical regions on both sides of equatorial zone, the richest are the coastal regions of temperate and subtropical latitudes. The annual production of phytoplankton in the World Ocean is 550 billion tons (according to the estimate of the Soviet oceanologist V.G. Bogorov), which is almost 10 times higher than the total production of the entire animal population of the ocean.

Many planktonic animals make regular vertical migrations with an amplitude of hundreds of m, sometimes over 1 km, facilitating the transfer of food resources from the surface layers rich in them to the depths and providing food to the deep-sea ocean. Due to the ability to migrate vertical zoning P. is less clearly expressed than benthos (see Marine fauna). Many planktonic organisms have the ability to glow (bioluminescence). Some can serve as indicators of the degree of pollution of a reservoir, because are sensitive to pollution to varying degrees.

P., directly or through intermediate links in food chains, serves as a source of nutrition for many commercial animals: squid, fish, whales, etc. Among planktonic organisms, some crustaceans (shrimps, mysids) are fished. IN last years All higher value Antarctic crustaceans, euphausians (krill), sometimes form huge aggregations (up to 15 kg/m3), are acquiring fisheries. The development of methods for using and catching marine parasites is promising, because its reserves are many times greater than the reserves of all marine organisms hunted so far.

Lit.: Zenkevich L. A., Fauna and biological productivity of the sea, vol. 1≈2, M., 1947≈51; Life of fresh waters of the USSR, vol. 1≈3, M.≈L., 1940≈50; Bogorov V.G., Productivity of the ocean, in the book: Basic problems of oceanology, M., 1968; Biology of the Pacific Ocean. Plankton, M., 1967 ( Pacific Ocean, vol. 7, book. 1); Vinogradov M. E., Vertical distribution of oceanic zooplankton, M., 1968; Beklemishev K.V., Ecology and biogeography of the pelagic zone, M., 1969; Kiselev I. A., Plankton of the seas and continental reservoirs, vol. 1, L., 1969.

G. M. Belyaev.

Wikipedia

Plankton

(Hyperia macrocephala)

Plankton (disambiguation)

• Plankton- heterogeneous, mostly small organisms that drift freely in the water column and are unable to resist the current.
• Office plankton is a modern slang expression used to refer to "white collar" - low-level office workers.
• Sheldon Plankton is a character from the animated series SpongeBob SquarePants.

Examples of the use of the word plankton in literature.

I went to Buenaventura and got a job on a ship, a Chinese assembler plankton.

Constructions of corals and calcareous algae, continuous over thousands of kilometers of film plankton ocean, Sargasso Sea, taiga Western Siberia or hylea tropical Africa provide such examples.

And the tunas themselves chased the cephalopods, and the cephalopods chased a school of silver sardines, which in turn set their sights on the microscopic organisms of the ocean plankton.

There they hang one above the other giant jellyfish and deadly goads pierce the water to the very bottom - the smallest plankton will not leak through the wall.

Although, by the way, I myself am not averse to drinking some plankton, otherwise yesterday they sold us mossy moose nostrils under the guise of a delicacy and forced us to fill it all with strawberry liqueur.

And I slowly passed through the trembling thin film from the sunny ocean afternoon into the light green, thickly infused with plankton, heated surface layer.

It is divided into two main groups: zoo plankton, consisting of animal microorganisms and fish eggs, and phyto plankton, or vegetable plankton, consisting of tiny algae.

We analyzed samples in both Indian and Atlantic plankton, and it turned out that there was ascorbic acid in it - the cat cried.

But Valery still spoke: “I once prepared an article by a foreigner about the fact that the blossoming plankton kills animals.

You just had to soak it up like a fish. plankton, and then prevent it from leaking out again.

We were going to do this using a device that hydrobiologists usually used to collect plankton.

During the last expedition, hydrobiologists gave us a whole mug plankton presented.

How not to get into a philosophical mood when plankton and the stars are the same, and the world is the same as it was long before the human eye saw it, and billions of busy fingers began to transform it.

To determine the nature and extent of damage caused fisheries as a result of pollution of the reservoir, to establish the causes and circumstances of the death of fish and plankton To determine the prospects for the restoration of food organisms in the reservoir, an ichthyological examination is assigned.

Sometimes, by throwing a large piece of cloth overboard and dragging it behind the ship, they managed to catch a little plankton, but eating it is like chewing coarse sand, bitter and unpleasant to the taste.

The word "plankton" comes from the Greek planktos, which means " wandering" This is not accidental - plankton really cannot resist the action of the current, unlike its closest “colleague” - nekton. However, we should not talk about plankton as a static mass of microscopic organisms. Although plankton consists mostly of tiny crustaceans, diatoms, fish larvae and plants, it also contains quite a few major representatives, such as small jellyfish. Some life forms can move vertically hundreds of meters during the course of a day. This phenomenon is called " daily vertical migration».

Plankton is divided into several groups:

1. Phytoplankton. The word comes from Greek phyton, which translates as " plant" It consists of small algae that float at the very surface of the water, where there is a lot of sunlight necessary for photosynthesis.
2. Zooplankton. From zoo- animal. Consists of protozoa and multicellular animals such as crustaceans. Zooplankton feed on phytoplankton.
3. Bacterioplankton. Consists of bacteria and archaea that participate in the process of remineralization, i.e. transformation of organic forms into inorganic ones.

Thus, this classification divides all plankton into three large groups: producers (phytoplankton), consumers (zooplankton) and utilizers (bacterioplankton).

There is another classification that divides plankton according to the size of animal forms, starting with viruses ( nannoplankton) and ending megaplankton, consisting of large (more than 2 cm) jellyfish, cephalopods, ctenophores, etc. The most common on our planet is nannoplankton, consisting of animals less than 2 microns. The discovery of the existence of this type of plankton occurred quite recently, in the 1980s.

Plankton are distributed throughout the world's oceans. The main condition for its formation is a sufficient amount of sunlight and the presence of organic nutrients in the water - nitrates and phosphates. Moreover, often the determining factor is the second one. Thus, in tropical and subtropical waters there is quite a lot of light throughout the year, but the small amount of organic compounds causes a low content of plankton in the water.

The importance of plankton in the world's oceans can hardly be overestimated. It acts as a feeder for most fish when they are young. Currents collect plankton into so-called feeding fields, where cetaceans and whale sharks graze. Some whales even make seasonal migrations, following the plankton fields.

Small plants on the surface of the water participate in photosynthesis and are an important element of the entire oxygen cycle system on the planet. The volume of phytoplankton in the world's oceans is enormous, so one should not write it off by assuming that only land plants produce oxygen. Plankton is also the largest source of carbon on Earth. The fact is that using it as food, animals convert plankton into biological mass, which then settles on seabed, because heavier than water. This process is known in scientific circles as " biological pump».

The importance of studying plankton is emphasized by the fact that science has even identified a separate section in biology that deals with its study - planktonology.

A collection of microscopic plants and plants that move by winds and currents near the surface of the oceans is collectively called plankton. Most of these microorganisms are simple, round and single-celled.

But despite the small size of each of them, the importance of plankton as a whole is difficult to overestimate, since it is the basis of any food chain.
Depending on their composition, plankton is divided into two types - phytoplankton (microscopic plants and bacteria) and zooplankton (tiny animals). Both types are important indicators of condition environment and the water world.
Phytoplankton inhabit the illuminated areas of the sea and their reproduction depends on sunlight and nutrients. It is very sensitive to temperature changes. The simplest structures of these organisms contain the pigment chlorophyll, with the participation of which the process of photosynthesis occurs, in which water molecules and atmospheric carbon dioxide combine to form carbohydrates, thereby synthesizing plant foods. It is chlorophyll that gives phytoplankton their greenish tint. Under ideal conditions, phytoplankton grow so quickly and in such quantities that they “bloom” across the entire surface of the ocean and become visible to the naked eye.
A single phytoplankter lives at most for a day or two. When it dies, it sinks to the ocean floor and replenishes the plant and animal material that had previously settled there. Thus, over millennia, the ocean floor has become the largest reservoir of atmospheric carbon, 90% of which, according to rough estimates, accumulated there.
Zooplankton consists of numerous microscopic animals, fish eggs, jellyfish larvae, squid and snails, and other invertebrates.
Zooplankton inhabit both illuminated zones and the deep layers of the ocean. Like plant microorganisms, these creatures are the most important indicator of water quality. Zooplankton feed on phytoplankton and, in turn, provide a vital source of food for fish and their young. Dense accumulations of zooplankton indicate that there should be a lot of fish in these places.
Krill are small, pink, shrimp-like crustaceans ranging from 7 mm to 5 cm in length. There are over 84 species of krill, many of which are specific to their region. Krill live in large aggregations in illuminated and twilight zones World Ocean. Some of its species are capable of bioluminescence.
Krill feed primarily on phytoplankton ( individual species- and zooplankton) and reproduces in such quantities that in some places “clouds of krill” cover the water surface with a thick layer. Such “feeders” attract many ocean inhabitants: whales, fish, manta rays, squid, seals, penguins and other seabirds. For them, krill is the most main source life, and if its numbers decrease, then the populations of these higher-lying forms in the food pyramid also decrease noticeably.
IN daytime krill accumulate at depths of up to one hundred meters, and some of its species dive even lower; at night it floats to the surface. These daily migrations help them accumulate energy and avoid predators. These small crustaceans are not able to swim fast enough to withstand winds and currents.

Krill are swimming crustaceans with a segmented body, tough top part shell and numerous legs B warm waters on a summer night, a female krill lays up to a thousand eggs, which then slowly sink to depth. Most of them are eaten by fish and other sea ​​creatures, and from the remaining ones, larvae develop, which rise to the surface and join the zooplankton. Growing up, crustaceans molt several times, shedding their external skeleton.

In addition to small crustaceans and algae, many in the ocean prefer to swim with the current. Everyone sea ​​creatures and all plants that live in the water column and are not able to resist being transported from place to place by waves, winds and currents are called plankton. "Planktos" means "wandering" in Greek. Plankton wanders throughout the ocean: wherever it goes, it’s good, but if it’s bad, no one can do anything.

Plankton in the ocean - phytoplankton and zooplankton

Plankton contains both plants and animals. Moreover, they can be either microscopic in size or quite large: for example, the cyanea jellyfish also moves at the will of the waves, and its bell reaches 2 m in diameter. Sargassum algae, already known to us, usually does not grow less than a meter in length, and by all indications they belong specifically to plankton.

However, most of the “wandering” ones are not very tall. Therefore, when they say about some animal that it feeds on plankton, then this name primarily means krill and other small things.

All floating plants are called phytoplankton. Due to it, zooplankton exists - these are radiolarians, nocturnal moths and other small animals, krill, jellyfish, and fish larvae. Even bottom inhabitants in their early, larval age quite often join small things freely floating near the surface. The food there is better (which means you can grow up faster), and it’s more convenient to move away from your homeland.

If everyone sits on the same section of the bottom, then there may not be enough food, but otherwise you might be lucky enough to find free place? Therefore, next to crustaceans you can find, for example, future corals - at this age they do not look like themselves, but rather resemble some kind of tiny jellyfish.

Plankton in the ocean are zooplankton - there are about ten times more of them than phytoplankton. It would seem that in this case it is impossible for the animals to feed themselves, because they will eat everything at once! But we must remember that the basis of phytoplankton is made up of tiny algae, and they grow and reproduce much faster than animals, and manage to produce 550 billion tons of live weight (scientifically called biomass) per year - ten times more than all animals ocean, from krill to whales!

Where this biomass disappears can be seen in simple example. In order for a school of herring to gain 10 kg in weight, it needs to eat 100 kg of zooplankton - mainly krill. And in order to grow that much krill, you need a ton of diatoms. So, when you buy a half-kilogram herring in the store, you bring home a tightly packed bag of algae weighing 50 kg!

This relationship is called a food chain. As you can easily see, the further we go along it, the more we need the initial product - phytoplankton. What if we add another link to this chain?

Let’s say that salmon eats 10 kg of young herring to gain one kilogram, a seal eats salmon, and a seal eats polar bear... So, to grow one (weighing 500 kg), you need 50 thousand tons of algae?! Interesting problem about plankton!

Still a little less. After all, the white one feeds not only on seals, but also on everything else that can be caught - salmon, for example. At the same time, it descends one step closer to the algae. Typically, animals are not strictly tied to their place in the food chain, but feed on what is more profitable or easier for them to obtain. Eating seal is good, a lot of meat at once. There are no seals, but there is a herring - the bear will eat it. Although he will have to spend more energy, try to catch this nimble fish without nets! In this case, most likely, the bear will not fully recover its hunting costs.

It is most advantageous to stand close to the beginning of the food chain; and it is even more profitable that the chain does not continue further, that is, that no one eats it. Plankton - Krill with its multi-ton accumulations that cannot escape and which you just need to find and strain (just as the crustaceans themselves do with diatoms...) is one of the most satisfying dishes in the ocean. And there is plenty of this dish for everyone.

By the way, the largest animals in the world are blue whales(maximum length 33 m and weight - 190 t), whale sharks(18 m and 15 t), giant manta rays (“only” 7 m and 4 t) - they all feed on zooplankton, for them plankton is the main food! Wherein big sizes help them remain last in the chain: few would attack such a giant!

Chains of gravediggers, or saprophytes, will eat the corpse of a whale, then they will also die (if they do not fall into a chain of predators, of course, for example, into the tentacles of an octopus) - other bottom inhabitants will take care of them... And so on until those bacteria that finally decompose animal matter into its simplest components - phosphates, nitrates and so on. And then bottom current will bring these substances to the surface, where they are useful to diatoms in their constant work.

Of course, plankton is very important in this entire cycle; we showed the relationship of these chains in a very simplified way and with only one, albeit very important, starting point - diatoms. But these three main food chains can be traced using the example of any plant or animal. Not only in the ocean, but also on land. This is one of general patterns life

By the way, the very first living creatures on our planet belonged... that's right, specifically to plankton! After all, life a long time ago, a billion years before our era, originated in the ocean. Scientists are still arguing how this happened, but they agree on one thing: the first living lumps swam freely in the water.

— phytoplankton and zooplankton are far from being studied yet!

What kind of natural phenomenon is plankton? This is not the name given to individual creatures, but to a group of aquatic organisms drifting in the water column. In the traditional classification, all inhabitants of the World Ocean, rivers and lakes on land are divided into three groups: nekton, benthos and plankton. The first are fish, squid, amphibians and other animals that actively move. Benthos (sponges, worms, mollusks and others) lead an attached lifestyle.

Plankton - what is it?

Translated from Greek, the name of organisms passively moving in water means “wandering”, “soaring”. Plankton are living beings that do not have active means of movement or have limited use of them. According to their belonging, plankton in the sea and fresh water bodies is divided into 3 main types: bacterial, phyto- and zooplankton. These organisms inhabit all bodies of water: from large fresh and sea water to small puddles.

Representatives of phytoplankton - algae and cyanobacteria - produce organic substances themselves. They need light to support photosynthesis. Zooplankton are protozoa, crustaceans, coelenterates, eggs, and larvae that feed on other small organisms.

There is another classification, which takes into account not the method of nutrition, but the size of the organisms. According to this system, groups are distinguished, starting with nannoplankton (viruses) and ending with megaplankton. The most common on the planet are the smallest creatures (about 2 microns). The existence of this group became known only in the 1980s. Megaplankton includes jellyfish, cephalopods, ctenophores and other aquatic inhabitants whose bodies are more than 2 cm in length.

Why don't plankton drown?

The body density of some organisms in the World Ocean is close in value to the specific gravity of water. Plankton is something very light that floats freely in its environment. Those living beings whose body density is greater than one are kept in suspension by their own motor activity.

Let us list the structural features of plankton that allow them to exist in the surface layer of water:

• microscopic or small in size;
• flat body shape;
• tissue saturation with water (up to 98%);
• secretion of copious mucus on the surface of the body;
• gas vacuoles;
• fatty inclusions;
• outgrowths, needles, hairs, bristles on the surface of the body;
• a small amount of heavy chemical elements in the tissues.

Each species has not all, but 2-3 devices from the list. There is one more feature that allows unicellular algae not to drown - uniting in colonies. Amazing ability some floating organisms - a change in density depending on water temperature. In a cold environment specific gravity the body increases, and when warm it decreases, which prevents immersion.

Phyto- and bacterioplankton

A group of organisms that makes up about 90% of all includes green sea ​​plankton and inhabitants These are volvox, dinophyte, euglena, cryptophyte algae, cyanides, green bacteria. They contain the pigment chlorophyll in their body, like land plants. Phytoplankton absorb carbon dioxide dissolved in water and use photosynthesis to obtain nutrients. Some representatives can fix nitrogen and hydrogen sulfide.

Favorable conditions for the growth and reproduction of phytoplankton:

• water rich in carbon dioxide;
• sunlight;
• presence of mineral elements;
• moderate temperature and salinity of water;
• insignificant depth.

Sometimes there is a sharp increase in phytoplankton or “blooming” of water. In the ocean, a similar phenomenon is observed over a vast area covering hundreds of square kilometers. Big environmental problem is "blooming" fresh water consumed for household and drinking purposes. Some representatives of phytoplankton produce toxins that are dangerous to fish and humans.

Zooplankton

What is animal plankton? Important component any aquatic ecosystem. Without this group of organisms, many inhabitants of the oceans, seas, rivers and lakes would not have received necessary nutrition. Some representatives of zooplankton have organs of locomotion, but do not use them to move long distances. Outgrowths, bristles, needles, and tentacles are necessary for such organisms to swim in the adjacent volume of water and vertically.

Wide horizontal distribution is ensured by movement “at the will of waves” and currents. Thus, larvae of crustaceans, echinoderms, and fish eggs remain in plankton for less than two months. During this period of time, they are carried away from their original habitat hundreds of kilometers. Among the zooplankton you can find the larval stages of sponges, anemones, worms, mollusks, crabs, lobsters and starfish. Numerous representatives of the group are crustaceans and krill, whose life almost entirely depends on the availability of food - diatoms.

Who eats plankton?

In the food chain, each organism is important; without it, the whole cannot exist. Small bacteria participate in photosynthesis and are producers of organic substances. Animal forms of organisms drifting in water are the main consumers of tiny algae and bacteria. Zooplankton serves as a link between bacteria, algae and large inhabitants reservoirs.

Many fish, shellfish, some birds feed on tiny crustaceans, krill and pteropods. The decline in plankton numbers threatens the well-being of the entire ecosystem of the World Ocean. Scientists are studying this problem in connection with climate changes on the planet, affecting the temperature, salinity and transparency of water - the habitat of plankton.