07.03.2020

Marine plankton. Interesting about plankton. The most diverse form of life and its economic value

A collection of microscopic plants and plants that are moved by winds and currents near the surface of the oceans is collectively referred to as plankton. Most of these microorganisms are simple, round and unicellular.

But despite such an insignificant size of each of them, the importance of plankton as a whole can hardly be overestimated, since it is the basis of any food chain.
Depending on the composition, plankton is divided into two types - phytoplankton (microscopic plants and bacteria) and zooplankton (the smallest animals). Both types are an important indicator of the condition environment and the water world.
Phytoplankton inhabits the illuminated areas of the sea and its 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 is carried out, in which water molecules and atmospheric carbon dioxide combine, turning into carbohydrates, thereby synthesizing vegetable food. Chlorophyll is what gives phytoplankton their greenish tint. IN ideal conditions phytoplankton grows so rapidly and in such numbers that they "bloom" over the entire surface of the ocean and become visible to the naked eye.
A single phytoplankter lives on the strength of a day or two. When it dies, it sinks to the bottom of the ocean and replenishes the plant and animal material that settled there earlier. Thus, over the millennia, the ocean floor has become the largest reservoir of atmospheric carbon, 90% of which, according to rough calculations, has accumulated there.
Zooplankton consists of numerous microscopic animals, fish eggs, jellyfish larvae, squid and snails and other invertebrates.
Zooplankton inhabits both the illuminated zones and the deep layers of the ocean. Like plant microorganisms, these creatures are a critical indicator of water quality. Zooplankton feed on phytoplankton and, in turn, are a vital food source for fish and their fry. Dense accumulations of zooplankton indicate that there should be a lot of fish in these places.
Krill are small, pink, shrimp-like crustaceans 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 the illuminated and twilight zones of the oceans. Some of its species are capable of bioluminescence.
Krill feeds mainly on phytoplankton (some species also on zooplankton) and breeds in such quantity that in some places "clouds of krill" cover the water surface with a thick layer. Such "feeders" attract many inhabitants of the ocean: whales, fish, manta rays, squid, seals, penguins and other sea birds. For them, krill is the most important source of life, and if their numbers fall, then the populations of these higher forms in the food pyramid are noticeably reduced.
IN daytime krill accumulate at depths of up to a hundred meters, and some of its species sink even lower; at night it floats to the surface. Such diurnal migrations help them store energy and avoid predators. These small crustaceans are not able to swim fast enough to withstand winds and currents.

Krill are floating crustaceans with a segmented body, a rigid upper part of the shell and numerous legs. In warm waters in midsummer night the female krill lays up to a thousand eggs, which then slowly sink to the depths. Most of them are eaten by fish and other sea creatures, and from the rest, larvae develop, which rise to the surface and merge with zooplankton. Growing up, crustaceans molt several times, shedding their outer skeleton.

Plankton consists of organisms that live freely in the water column and are not able to counteract their own movements. aquatic environment(currents, convection currents, etc.) due to the absence or relatively underdevelopment they have organs of motion. Plankton are systematically divided into plant plankton, or phytoplankton, and animal plankton, or zooplankton.

The composition of plankton includes, on the one hand, holoplanktic organisms, which spend their entire life, including also the period of development, out of contact with a solid substrate, and on the other hand, meroplanktic organisms that spend a certain period of their lives at the bottom of reservoirs. The latter include, for example, planktic larvae of worms, echinoderms, mollusks, crustaceans and other marine bottom animals, hydroid jellyfish budding from polyps, as well as many organisms living in the coastal region, cysts and resting eggs of which for further development sink to the bottom.

Depending on the size of organisms, plankton is divided into the following groups.

1. Ultraplankton (bacteria) - the size of organisms does not exceed a few microns, the lower limit is beyond visibility.

2. Nannoplankton, or dwarf plankton (the smallest lower plants and protozoa), - the size of organisms is measured in microns and tens of microns; due to their negligible size, nannoplankton organisms pass through the thickest silk gas, can only be studied using centrifugation or chamber method, therefore this group of organisms is also called centrifugal or chamber plankton.

3. Microplankton ( main part phytoplankton, as well as ciliates, rotifers, small crustaceans, etc.) - the size of organisms is measured in tenths and hundredths of a millimeter; It is caught by planktic nets of thick silken gas or by sedimentation, therefore it is also called net, or sedimentary, plankton.

4. Mesoplancon ( major representatives phytoplankton, the main part of the zooplankton of the seas) - the size of organisms is measured in millimeters; caught by planktic nets of rare silken gas - net plankton.

5. Macroplankton ( higher crayfish, jellyfish, pelagic worms, etc.) - the size of organisms is measured in centimeters, found exclusively in the seas; caught in large planktic nets.

6. Megaloplankton (many scyphoid jellyfish, large siphonophores, etc.) - the size of organisms is measured in tens of centimeters; found exclusively in the seas.

A distinctive feature of planktic organisms - their ability to be suspended in water - leaves a certain imprint on their structure.

plankton

Dictionary of medical terms

plankton (Greek planktos wandering)

a set of animal and plant organisms inhabiting the water column and passively carried by the current; characterizes the pollution of the 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 the seas and rivers and move only by the force of the flow of water. plant plankton. Animal plankton. The Papaninites discovered plankton on the most northern latitudes at the pole.

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

plankton

A, m. (special). The totality of animal and plant organisms that live in the water column and are carried by the force of the current.

adj. planktonic, th, th.

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

plankton

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

Encyclopedic Dictionary, 1998

plankton

PLANKTON (from the Greek. planktos - wandering) a set of organisms that live in the water column and are unable to resist the transfer by the current. Plankton is made up of many bacteria, diatoms and some other algae (phytoplankton), protozoa, some coelenterates, molluscs, crustaceans, tunicates, fish eggs and larvae, and larvae of many invertebrate animals (zooplankton). Plankton directly or through intermediate links food chains serves as food for all other animals living in water bodies. See 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 the transfer by currents. P.'s composition 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 the lake plankton, which is limnoplankton, and the river plankton, which is potamoplankton.

Plant photosynthetic planktonic organisms need 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, peridine and coccolithophorids; in fresh waters - from diatoms, blue-green and some groups of green algae. In freshwater zooplankton, copepods and cladocerans and rotifers; in the marine ≈ crustaceans dominate (mainly copepods, as well as mysids, euphausians, shrimps, etc.), protozoans (radiolaria, foraminifera, ciliates tintinnida), intestinal cavities (jellyfish, siphonophores, ctenophores), winged mollusks, tunicates (appendicularians, salps , kegs, pyrosomes), eggs and larvae of fish, larvae of various invertebrates, including many benthic. Species diversity P. greatest in tropical waters ocean.

The sizes of P.'s organisms range from a few microns to several meters. Therefore, they usually distinguish between: nannoplankton (bacteria, the smallest unicellular algae), microplankton (most algae, protozoa, rotifers, many larvae), mesoplankton (copepods and cladocerans and other animals less than 1 cm), macroplankton (many mysids, shrimps, jellyfish, and other relatively large animals) and megaloplankton, to which include a few of the largest planktonic animals (for example, the comb jellyfish venus belt up to 1.5 m long, cyanide jellyfish up to 2 m in diameter with tentacles up to 30 m, pyrosom colonies 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 devices that facilitate soaring in water: reducing the specific mass of the body (gas and fat inclusions, water saturation and gelatinization of tissues, 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, due to which most aquatic animals live. In the shallow coastal parts of water bodies, organic matter is also produced by benthic plants—phytobenthos. The abundance of phytoplankton in various parts water bodies depends on the amount of nutrients necessary for it in the surface layers. Limiting in this respect mainly phosphates, nitrogen compounds, and for some organisms (diatoms, siliceous) and silicon compounds. Over the long history of the ocean, these substances have accumulated in large quantities in its depths, mainly as a result of the decomposition and mineralization of organic particles settling from upper layers. Therefore, the abundant development of phytoplankton occurs in areas of deep water rise (for example, in the area of the junction warm waters Gulf Stream and northern cold currents, in the zone of equatorial divergence of waters, in areas of negative winds near the coast, etc.). Since phytoplankton feed on small planktonic animals that serve as food for larger ones, areas greatest development phytoplankton are also characterized by an abundance of zooplankton and nekton. Much less and only local importance in the enrichment of surface waters with nutrients is the river runoff. The development of phytoplankton also depends on the intensity of illumination, which in cold and temperate waters causes seasonality in the development of P. In winter, despite the abundance of nutrients carried into the surface layers as a result of winter mixing of waters, phytoplankton is scarce due to lack of light. In spring, the rapid development of phytoplankton begins, and after it, zooplankton. As phytoplankton use nutrients, and also as a result of eating them 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. flowering of water, changing its color and reducing transparency. When some peridines bloom, toxic substances are released into the water, which can cause mass death of planktonic and nektonic animals.

The biomass of P. varies in different water bodies and their regions, as well as in different seasons. In the surface layer of the ocean, the biomass of phytoplankton usually varies from a few mg to several g/m3, zooplankton (mesoplankton) ≈ from tens of mg to 1 g/m3 or more. With depth P. becomes less various and its quantity quickly decreases. In the World Ocean, poor marine areas predominate in area over rich ones. P. is poorest in the central tropical regions on both sides of equatorial zone, the richest are coastal regions of temperate and subtropical latitudes. The annual production of phytoplankton in the World Ocean is 550 billion tons (according to 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 meters, sometimes more than 1 km, which contribute to the transfer of food resources from the surface layers rich in them to the depths and to provide food for deep-sea P. Due to the ability to migrate, the vertical zonality of P. is less pronounced than that of benthos ( see Marine fauna). Many planktonic organisms have the ability to glow (bioluminescence). Some can serve as indicators of the degree of pollution of the reservoir, tk. are sensitive to pollution to varying degrees.

P. directly or through intermediate links in food chains serves as a source of nutrition for many game animals: squid, fish, whales, etc. Of the planktonic organisms, some crustaceans (shrimps, mysids) serve as objects of fishing. IN last years The fishery of Antarctic crustaceans, euphausiidae (krill), which sometimes form huge aggregations (up to 15 kg/m3), is becoming increasingly important. The development of methods for using and catching marine P. is promising, because. its reserves are many times greater than the reserves of all marine organisms that have been harvested 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., Ocean productivity, 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 pelagial, 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, freely drifting in the water column and not able to resist the flow.
Office plankton is a modern slang expression used to refer to "white-collar" - small office workers.
Sheldon Plankton is a character from the animated series SpongeBob SquarePants.

Examples of the use of the word plankton in the literature.

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

Buildings of corals and calcareous algae, continuous films for thousands of kilometers plankton ocean, Sargasso Sea, taiga Western Siberia or hylaea tropical Africa provide such examples.

And the tunas themselves were chasing cephalopods, and the cephalopods were chasing a flock of silvery sardines, which in turn set their sights on microscopic organisms of the ocean plankton.

There, one above the other, giant Medusa hang and deadly goads penetrate the water to the very bottom - the smallest plankton won't seep through the wall.

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

And I slowly passed through the quivering thin film from a sunny oceanic noon to a light green, heavily infused with plankton, heated near-surface layer.

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

We both in the Indian and in the Atlantic did sample analyzes plankton, and it turned out that the ascorbic acid in it - the cat cried.

But Valery nevertheless spoke: - Once I was preparing an article by a foreigner that a blooming plankton kills animals.

You just had to soak it up like a fish plankton and then don't let it leak again.

We were going to do this with the help of a device that hydrobiologists usually used to collect plankton.

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

How not to tune in philosophically 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 to the fisheries as a result of pollution of the reservoir, to establish the causes and circumstances of the death of fish and plankton, determining the prospects for the restoration of food organisms in the reservoir, an ichthyological examination is assigned.

Sometimes, 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 in taste.

Plankton

Plankton is made up of a wide variety of organisms. Some of them are larval forms of benthic species, others life cycle passes completely in the water column, away from a solid substrate. Part of the plankton is represented by unicellular algae capable of photosynthesis, i.e. converting carbon dioxide and water into simple sugars and free oxygen. Because photosynthesis requires light, most of these organisms are found in top layer water.

Planktonic algae belong to several large taxonomic groups, the main of which are diatoms (diatoms) and dinoflagellates. The cells of the first are covered with a silica shell. In some places, there are so many diatoms that their dead remains, settling to the bottom, form special diatom silts, which over millions of years have turned into thick layers of rock - diatomite.

Phytoplankton

Diatoms, dinoflagellates and other planktonic algae together make up phytoplankton. Like other organisms capable of converting inorganic substances into organic, i.e. in their own food, they are called autotrophs, which means "self-feeding" in Greek. Together with other autotrophs, such as land plants, they combine to form environmental group producers, since they are the first link in various food chains.

Algal bloom. In many seas, especially in temperate climate zone, in certain seasons, usually in winter, the water is enriched with mineral salts necessary for the reproduction of phytoplankton. When the water warms up in spring, microscopic algae begin to rapidly divide, explosively increasing their numbers, and the sea becomes cloudy, and sometimes even turns into an unusual color. This phenomenon is called an algal bloom. Usually, it declines and stops as the reserves of the necessary salts are depleted: phytoplankton organisms in the mass die and are eaten by zooplankton until a temporary population equilibrium is established again.

Red tides. Usually, algal blooms are accompanied by an increase in the number of zooplankton, which, feeding on phytoplankton, restrains to a certain extent the growth of its mass. However, at times it increases so rapidly that the process gets out of control. This is especially often observed during the rapid reproduction of one of the species of dinoflagellates. Sea water near the coast, it takes on the color and texture of tomato soup - hence the name "red tide". The main thing is that the "blooming" algae contains a toxin that is dangerous for many fish and shellfish. Red tides in Florida, Africa and other regions led to the death of many hundreds of thousands of these animals.

Shellfish poisoning. Some types of phytoplankton contain nerve poison. bivalves, in particular mussels, feed on phytoplankton, therefore, in certain seasons, usually in the warm months, they also eat huge amounts of “blooming” toxic algae, accumulating their poison in their tissues without visible harm to themselves. However, eating such shellfish can cause severe poisoning.

Productivity. Phytoplankton actively breeds mainly in coastal waters, and the farther from the coast, the lower its productivity. That is why in the open ocean, especially in the tropics, the water is very clear and blue, and off the coast, especially in temperate zone, often yellowish, greenish or brown.

A sharp increase in the concentration of mineral salts dissolved in water, necessary for the development of phytoplankton, is associated with currents that raise these substances from the bottom layers or carry them out of estuaries, where many remains of dead organisms mineralized by bacteria accumulate. In some parts of the ocean there are so-called. water rises, or upwellings, are peculiar currents that carry cold ocean water rich in nutrients (biogenic) elements from great depths to shallow coastal waters. Upwelling zones are associated with high productivity of phyto- and zooplankton, therefore they attract a large number of fish.

Zooplankton

The continuously dividing planktonic algae are eaten with no less intensity by zooplankton, which maintains their numbers at an approximately constant level. Planktonic animals include mainly tiny crustaceans, jellyfish and the larvae of thousands of other marine animal species. Most taxonomic types of invertebrates are represented in zooplankton.

Bioindicators. Like benthic animals, zooplankton forms can exist only at certain levels of temperature, salinity, illumination, and water velocity. The requirements of some of them to environmental conditions are so specific that the presence of these organisms can be used to judge the features marine environment generally. Such organisms are commonly referred to as bioindicators.

Although most zooplanktonic forms are able to move actively to some extent, in general these animals drift passively with the current. However, many of them make daily vertical migrations, sometimes over distances of up to several hundred meters, in response to diurnal changes in illumination. Some species are adapted to life in the near-surface layer, where the illumination changes cyclically, while others prefer the more or less constant twilight that is found in the daytime at great depths.

Deep-water scattering layer. Many planktonic animals form dense aggregations at medium depths. Such accumulations were first detected by instruments for measuring depth - echo sounders: the sound waves sent by them, obviously not reaching the bottom, were scattered by some kind of obstacle. Hence the term arose - deep-water scattering layer (DSL). Its presence indicates that large numbers of organisms can live far from phytoplankton producers.

Zooplankton, following phytoplankton, concentrates in nutrient-rich coastal upwelling zones. The increased abundance of marine animals here is undoubtedly a consequence of active breeding algae.

Nekton

Nekton - a group of actively swimming organisms that can resist the force of the current and move considerable distances. N. includes fish, squid, cetaceans, pinnipeds, water snakes, turtles, penguins. Nektonic animals are characterized by a streamlined body shape and well-developed organs of movement. N. is opposed to plankton; An intermediate position between them is occupied by micronekton, represented by animals capable of limited active movements: juveniles and small species of fish and squid, large shrimps, euphausian crustaceans, etc.

Representatives of the nekton group live in the water column and are able to move regardless of the current. These include the water mite. In general, all water mites are distinguished by a beautiful, often variegated or bright color. The body of water mites is shortened, not segmented, the head, chest and abdomen are fused together. At the marginal edge of the head end, eyes arranged in pairs are placed, enclosed in chitinous capsules. The legs of water mites are swimming, covered with numerous hairs.

Eggs and larvae of fish, larvae of various invertebrates (zooplankton). Plankton, directly or through intermediate links in the food chain, is food for most other aquatic animals.

The term plankton was first coined by the German oceanographer Victor Hensen in the late 1880s.

Classification

Depending on the way of life, plankton is divided into:

holoplankton - spends the entire life cycle in the form of plankton;
meroplankton - existing in the form of plankton only part of life, for example, sea worms, fish.

Plankton is made up of many bacteria, diatoms and some other algae (phytoplankton), protozoa, some coelenterates, molluscs, crustaceans, tunicates, fish eggs and larvae, and larvae of many invertebrate animals (zooplankton). Plankton directly or through intermediate links of food chains serves as food for other animals living in water bodies (except for phytoplankton, benthic macrophytes and microalgae can also be the first link in food chains). Plankton is a mass of plants and animals, most of which are microscopic in size. Many of them are capable of independent active movement, but they are not good enough swimmers to resist currents, so planktonic organisms move along with water masses. Planktonic organisms are found at any depth, but near-surface, well-lit water layers are richest in them, where they form floating "forage grounds" for larger animals. Plant photosynthetic planktonic organisms need sunlight and inhabit surface waters, mainly to a depth of 50-100 m - the so-called euphotic layer. Bacteria and zooplankton inhabit the entire water column to the maximum depths. Marine phytoplankton consists mainly of diatoms, peridine and coccolithophorids; in fresh waters - from diatoms, blue-green and some groups of green algae. In freshwater zooplankton, copepods and cladocerans and rotifers are the most numerous; in the marine crustaceans dominate (mainly copepods, as well as mysids, euphausiae, shrimp, etc.), protozoa are numerous (radiolaria, foraminifera, ciliates tintinnida), intestinal cavities (jellyfish, siphonophores, ctenophores), winged molluscs, tunicates (appendicularians, salps, kegs, pyrosomes), fish eggs, larvae of various invertebrates, including many benthic. The species diversity of plankton is greatest in the tropical waters of the ocean.

There are several classifications of plankton depending on their size. The most common is the following:

megaplankton (0.2 - 2 m) - jellyfish
macroplankton (0.02 - 0.20 m) - many mysids, shrimps, jellyfish and other relatively large animals
mesoplankton (0.0002 - 0.02 m) - copepods and cladocerans and other animals less than 2 cm
microplankton (20 - 200 microns) - most algae, protozoa, rotifers, many larvae
nanoplankton (2 - 20 microns) - small unicellular algae, some large bacteria
picoplankton (0.2-2 microns) - bacteria, the smallest unicellular algae.
femtoplankton (<0,2 мкм) - океанические вирусы.

According to modern data, picoplankton provides the largest production in ocean waters. Eukaryotic algae recently discovered in its composition (for example, prasinophyte genera Osteococcus) are the smallest eukaryotes.

Zooplankton is the most numerous group of aquatic organisms of great ecological and economic importance. It consumes organic matter formed in water bodies and brought from outside, is responsible for the self-purification of water bodies and watercourses, forms the basis of nutrition for most fish species, and finally, plankton serves as an excellent indicator for assessing water quality.

Studies of zooplankton organisms help determine the pollution of water bodies and determine the ecological features of a particular area. Any aquatic ecosystem, being in balance with environmental factors, has a complex system of mobile biological connections that are disturbed under the influence of anthropogenic factors. First of all, the influence of anthropogenic factors, and pollution in particular, affects the species composition of aquatic communities and the ratio of the abundance of their constituent species.

Marine plankton. Interesting about plankton. The most diverse form of life and its economic value

plankton

Dictionary of medical terms

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

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

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

Encyclopedic Dictionary, 1998

Wikipedia

Examples of the use of the word plankton in the literature.

Plankton

Phytoplankton

Zooplankton

Nekton

Classification

see also

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