Presentation on the topic "Lakes of Russia" in powerpoint format. Lakes by origin Classification of lakes by origin

Presentation on the topic "Lakes of Russia" on geography in powerpoint format. The purpose of this presentation for schoolchildren is to give an idea of the location, characteristics, origin of lakes in our country, and their role in human life.

Fragments from the presentation

Lakes- These are closed basins filled with water.

Lakes are fresh and salty.

Lakes can be drained or drainless.

Sewage lakes, as a rule, fresh, since the rivers flowing from the lake also carry salt.
Endorheic lakes- salty, they flow into them, but not a single river flows out. Salts accumulate in such a lake.

The lakes vary in origin.

The deepest lakes are of tectonic origin (in faults, cracks in the earth's crust). Such lakes are oblong: narrow and long. The deepest lake in the world, Baikal (1637 m), has this origin.
Lakes of glacial-tectonic origin (deepened under the weight of a glacier) are located in the north-west of the Russian Plain. The largest of them are Ladoga and Onega.
Moraine lakes occupy depressions between moraine basins, which were formed as a result of ancient glaciation.
Volcanic lakes are located in the craters of volcanoes on the Kuril Islands, on the Kamchatka Peninsula.
Oxbow lakes are common in river valleys
Karst lakes are formed in surface sinkholes and wells associated with the dissolution of rocks by natural waters.
Man is the force that creates artificial reservoirs - ponds and larger ones - reservoirs. The largest reservoirs were built on the Volga - Rybinsk, Kuibyshev.

"Water hunger" of the planet.

The main danger is widespread pollution of river and lake waters.
Man takes a huge amount of fresh water from rivers, lakes and groundwater. This can only be explained by insane wastefulness!
However, wasteful consumption of fresh water is not the main and not the most dangerous source of “water hunger” on Earth.
As a result, already now about 1/3 of the population of our planet lacks clean water. The lack of clean water is becoming one of the most important factors limiting the progressive development of mankind.

What is a lake? How is it different from a pond? How do they appear on Earth?

There are many wonders on our planet that we do not see only because we are in too much of a hurry. Roads have replaced nature travel, but once you stop and get out of the car, you can see a small pond.

Several hundred years ago, there may have been a collision with a “guest” from deep space. Or a supervolcano erupted. Nature leaves traces of the past under our feet; it’s up to you to read them or not.

What is a lake and what are its signs

The name of this type of reservoir translated from Old English (sounds like “laka”) is translated as pond or pool. From other languages it can be translated as puddle, stream and even waterway.

The main problem in the definition is the confusion of the natural source of fresh (salt) water described here with an ordinary pond. To exclude such a connection, some definitions are interpreted to indicate the size of the source from two to five hectares.

No matter what size the lake is, it has the main difference from rivers and seas is isolation. Not even the largest lake is connected to the ocean. As a rule, it is surrounded by land along its perimeter.

The bulk of lakes on planet Earth are filled with fresh water and have a drainage system.

Reservoirs where nature provides for the outflow of water in the form of rivers are called wastewater. If the water balance is maintained solely by evaporation and penetration underground, then they are called drainless.

Maline Lake (Canada)

The largest number of lakes are in Canada (there are about 32 thousand) and Russia (more than 2 million). Beautiful lake landscapes can be found in Finland (190 thousand).

In nature there are reservoirs of artificial origin created for agriculture, decorative and industrial purposes.

Types and classification of lakes

Scientists classify lakes into several types.

By origin:

Tectonic– lakes of tectonic origin are formed as a result of deformation of the earth’s crust.
The most famous is located on the territory of our country - lake. Baikal. This includes the lakes of the Caspian basin. Sometimes the soil simply subsides, forming thermokarst lakes.
Volcanic– occupying local volcanic depressions. For example, in craters (Craters) volcanic calderas (Calderas). Over time, such irregularities are filled with natural precipitation.
Crater Lake in Oregon

The creation process occurs quite quickly due to evaporation or the release of groundwater. Sometimes both lake names are mixed into one. An example is Crater Lake in Oregon, in the caldera of Mount Mazama.
Glacial– created under the direct influence of glaciers or continental glaciers. A wide variety of glacial processes create closed basins. Subspecies – car.
On the world map, something similar can be found in Antarctica - Lake Vostok.
Floodplain– form where sediment from a tributary dams the main river.
Estuary lakes of the Azov Sea. Sometimes large seas dry out, forming residual ones.
Landslides– lakes are common in mountainous areas where there was an earthquake.
Quake Lake in North America

Although landslide lakes can be large and quite deep, they are short-lived. Quake in North America, Montana.
Aeolian- These are lakes created by the wind. Example - lake. Moses Lake, Washington.
Coastal– are formed due to blockages of beach ridges by longline and other currents. Oz. Beregovoe, Kemerovo region, Russia.
Organic– created by the actions of plants and animals.
Peat- this is a form of organic lake - lake. Torfyanoe, Moscow, Russia.
Anthropogenic- These are artificially created lakes formed by human activity. They may be the result of deliberate damming of rivers and streams.
An example is a lake in Altai (Russia) near the Turquoise Katun tourist camp.
Meteorite– lakes created by catastrophic extraterrestrial impacts of either a meteorite or an asteroid.
Example - lake. Yanisjarvi, Russia, Republic of Karelia.

By type of mineralization:

By nutritional value:

By chemical composition:

Characteristics of famous lakes of the world in the table

The table provides a brief description of the most famous lakes in the world.

Conclusion

From the school course it is clear to us that most of the planet is covered with water. Some of them are deep lakes (like Baikal), some are shallow and very salty (like Sol-Iletsk). But any of them is a beautiful creation of the material world of the Earth, which sometimes tells us that nature is the most talented architect of the world in which we live.

Lakes are always and everywhere formed according to one scenario - a depression, lowland or fault is formed in the area for various reasons - a basin. If it is subsequently filled with water, it will form a lake. Everything else is not significant. The location and origin of lakes is associated with the climate of the area, which determines their nutrition and evaporation, as well as with factors contributing to the formation of lake depressions. Where the climate is humid, the lakes are deep, fresh and numerous. For the most part they are flowing here. In arid areas, lakes are shallow, often salty and drainless. Thus, the hydrochemical features of lakes are determined by their geographical location.

Lakes are usually classified according to four characteristics: the origin of lake basins; the origin of the water mass; water regime and mineral composition (salinity).

Based on their origin, there are 5 groups of lake basins. Tectonic lake basins are formed as a result of cracks, faults and subsidence of the earth's crust. Such lakes are distinguished by their steep slopes and depth. As an example - Lake Baikal, the Dead Sea, Chad, Titicaca.

Volcanic lake basins - formed in the craters of volcanoes or in the lowlands of lava fields. As an example, we can note Lake Kuril in Kamchatka, lakes in Java and New Zealand. The photo shows lakes in the craters of the Kelimutu volcano.

Glacial (moraine) lake basins are dug by moving glaciers with subsequent erosion and accumulation of water in front of glacial landforms. When a glacier melts, the material it brings is deposited in the form of hills, ridges, hills and depressions. Such lakes are usually narrow and long, stretched along the melting line of the glacier - lakes in Finland, Karelia, the Alps, the Urals, and the Caucasus.

Karst lake basins - they arose as a result of failures, soil sedimentation and erosion of soft rocks - limestone, gypsum, dolomite. As a result, small but deep lake basins are formed.

Dammed (dammed or dammed) lake basins - arise as a result of blocking the river bed by rock falls. This is how Lake Sevan and a number of lakes in the Alps, Himalayas and the Caucasus were formed.

But depressions suitable for filling with water can appear in other ways. Here everything depends on the location and climate - the proximity of the sea, rivers, strong winds, groundwater, layers of permafrost in the soil. The result is still the same - the formation of a basin and filling it with water.

Other types of lakes

Estuary lakes are located along the shores of the seas. They are coastal areas of the sea, separated from it by coastal spits.

Organogenic lakes appear over time among swamps and coral reefs. Floodplain lakes are associated with changes in the river bed - lakes of the Kuban floodplains, ilmen of the Volga delta. Such lakes have a characteristic horseshoe shape.

The wind creates aeolian lakes that form in blowing basins - Lake Teke, Lake Selecty in Kazakhstan and a number of others arose in this way.

Suffosion lakes appear where groundwater actively washes away small pieces of rock, causing the ground to settle. Such lakes are typical for the south of Western Siberia.

Thermokarst sinkhole lakes (pictured) appear when areas of permafrost melt. Dips form in the ground and fill with melt water. There are many such lakes in the Kolyma Lowland - the most lake region in Russia.

Based on the origin of water masses, lakes are divided into two types - atmospheric and relict. Atmospheric lakes have never been part of the oceans. There are the majority of such lakes on Earth. Relict (or residual) lakes appeared on the site of the retreated seas - the Caspian, Aral, Ladoga, Onega, Ilmen and others.

Based on their water regime, there are two types of lakes: drainage and drainless. Sewage lakes are lakes in which water is exchanged, rivers flow into and out of them. They are usually fresh. Such lakes are often located in areas of excess moisture.

Mineral lakes

Endorheic lakes have inflowing rivers, but no outflowing ones. The water consumption of such lakes is dominated by evaporation and all minerals remain in the reservoir. Most of them are salty. Such lakes are located in areas of insufficient moisture.

Based on salinity, lakes are divided into four types: fresh, salt, brackish and mineral. Fresh lakes - if the salinity does not exceed 1 ppm. Salt lakes - if the content of soluble substances in them is within the range of 24.7 - 47 ppm. Brackish - salinity up to 24 ppm. Mineral - 47 ppm. These can be soda, sulfate, chloride lakes. In mineral lakes, salts can precipitate, for example lakes Elton and Baskunchak, which are a source of salt production. The photo shows a salt lake in Kenya.

Lakes play an important role in the planet's ecosystem. They create a special microclimate favorable for different forms of life. Even when salted, they attract many different organisms. And freshwater forms its own balanced and surprisingly rich ecosystems. Geological forces tend to level the surface of the continent through erosion, and the accumulation of sediment leads to a decrease in the depth of the lake and its gradual disappearance. Biological and chemical reactions occur in lake waters, as a result of which some elements pass into bottom sediments or, conversely, dissolve in water. Bottom sediments change the topography of the lake bottom and, under certain conditions, can be transformed into rocks of organic origin. Overgrowing of lakes creates new forms of relief.

Most lakes are relatively young formations. One of the most ancient is Baikal. Its age is 25 - 30 million years. The largest of the lakes is the Caspian. Its area is about 368 thousand square kilometers. The deepest is Baikal - 1620 meters. I would like to hope that these amazing natural formations will remain in their pristine state for a long time.

Ecology, population of the lake bottom

Types of lakes, origin, characteristics:

Lake (O) is a water-filled basin or depression of the earth’s surface that has no connection with the sea; slow water exchange. Lakes are formed if the influx of water (surface and underground) into a basin is greater than the loss of water from this basin through evaporation, filtration, and runoff. The formation of basins is under the influence of endogenous and exogenous processes. Inland (endogenous) - formed as a result of tectonic and volcanic phenomena.

External (exogenous) - the activity of water, ice, wind, under the influence of which erosional, sinkhole, accumulative, aeolian and dam types of basins arise. More often, basins are formed under the influence of several factors, but one of them is the leading one (the basin of Lake Ladoga and Lake Onega are tectonic, but were subsequently processed by glaciers).

Based on the origin of the basin there are:

tectonic— formed in troughs of the earth’s surface: deep, large in area and elongated in length (Caspian, Aral, Ladoga, Onega, Baikal, Issyk-Kul);

volcanic- arose in craters extinct by a volcano; rounded outlines and funnel-shaped (Kuril Islands, Kamchatka, Armenian Highlands); meteorite - in depressions after the fall of meteorites (lake.

Kaali in Estonia);

glacial— as a result of the erosion-accumulation activity of a glacier, it “plows out” depressions in the earth’s surface, modifies pre-existing basins, and deposits the material it transports in the form of a moraine. Moraine lakes appear among moraine deposits.

Shapes: elongated lobed, oval (Karelia, Kola Peninsula).

Glacial lakes include tar and trade lakes - they are located on the slopes of mountains in thread-like depressions (kars) formed by the combined action of ice and frost weathering (Caucasus, Altai, Alps). In trough-like or trough-shaped valleys, which were previously eroded and then transformed by glacial gouging, commercial islands arise (Alps, Caucasus).

Water-erosive and water-accumulative lakes are located in river valleys, deltas, and on sea coasts. Floodplain lakes are located in river floodplains, called oxbow lakes - they are formed by completely separating the winding sections of the old channel from the river when it is straightened. They also occur when depressions and small depressions (saucers) found in the floodplains of rivers (Volga, Dnieper, Oka) are flooded during high water.

Plesovye O.

In the form of lake-like expansions of river channels and reaches, separated by dry sections of the channel when rivers dry up during low water periods.

Delta O.

(blocked branches) - in the deltas of large rivers ((Volga, Kuban).

Coastal islands—on sea coasts, as a result of the separation of shallow bays and bays from the sea by alluvial sand and clay spits, are called lagoons (Laleostomi). Estuary lakes - when expanded estuary sections of rivers are flooded by the sea and are separated from the sea by spits (Azov-Black Sea coast).

If fjords are gradually separated from the sea by debris or sediment, they turn into fiords.

Failed lakes are due to the leaching of rocks by underground and surface waters and the melting of fossil ice. These are O.karst, subsidence, thermokarst.

Karst O. - in places where limestone, dolomite, and gypsum occur, they are easily dissolved by water. The basins formed in this case are not brooms, round in shape, deep (Caucasus, Urals).

Subsidence O.

Due to the long-term removal of clay particles by groundwater or the washing out of salts by water, it leads to the formation of voids and subsidence of layers of pound.

Thermokarst O. - areas of permafrost - as a result of the melting of buried layers and lenses of ice and the associated subsidence of the soil; oval shape, shallow depths.

Aeolian O.

(deflationary) - in depressions, due to the wind blowing away small particles of soil in dry climates. The basins are small in size and shallow (between dunes and dunes in the Aral-Caspian lowland).

Dammed (dammed) lakes - arise when river valleys are blocked by mountain landslides, landslides, when rivers are dammed by lava flows, or glacial moraines (O. Ritsa in the Caucasus, S. Yevan). Shape - elongated, with the greatest depths near the dam.

Organogenic O.

These include secondary O. that arise in swamps; significant area and depth. Reservoirs created by artificial reservoirs, and reservoirs that appeared as a result. flooding of old quarries and salt mines (O. Razval in the Urals).

Ponds (digging)- dug lake-type reservoirs, many are formed in peat mines, sand and clay quarries.

Geographical distribution lakes are determined by physical and geographical conditions, of which climatic ones are of greater importance, determining the nutrition of oxygen. Therefore, in areas with a humid climate there is a lot of fresh water, and in arid areas there is little water, they are low-water, brackish and salty water (Transbaikalia, Dazakhstan). Lakes are often located in groups, forming lake countries (in Finland there are 35 thousand of them, covering 15% of the country's territory).

The altitude location of the lakes (in Tibet at 5000 m, in the Caucasus - 3600 m, in the Carpathians - 2000 m). There are lakes located below sea level (Dead Sea).

Ecological structure of the lake bottom

A lake is a water-filled basin or depression on the earth's surface that has no connection with the sea.

The lake basin is usually formed underwater terrace, which is characterized by a gradual slight decrease in land mass, then follows stall with a steeper angle of decline and turning into boiler, which occupies most of the lake bottom. According to the listed areas in lacustrine benthic, it is customary to distinguish littoral- coastal shallow waters, sublittoral, which extends to the lower limit of the distribution of bottom vegetation, and profundal, covering the remaining area of the lake bottom (available only in deep lakes).

Pelagial The lake is divided into the coastal zone, which lies above the underwater terrace, and the pelagic zone itself, located above the dump and the cauldron. During vertical stagnation, the water mass of lakes is divided into the upper layer - epilimnion, in which the temperature experiences sharp seasonal and daily fluctuations, the lower, or hypolimnion, where the temperature varies little throughout the year, and is intermediate, or metalimnion, - a layer of temperature jump (temperature difference between differently heated waters of the epi- and hypolimnion). The part of the lake basin filled with water to the height of the maximum level is called the lake bed, or lake bowl.

In the lake bed, coastal and deep areas are distinguished. In the coastal area, the processes of destruction of rocks that form the basin under the influence of wave action predominate; in the deep area, deposition of destruction products occurs.

All lakes in the geological sense are temporary formations and sooner or later disappear.

Lakes and their origin

This cycle of lake development (evolution) occurs continuously. There are the following stages of lake development:

1) youth stage - the initial relief of the basin remains unchanged;

2) stage of maturity - a coastal sandbank appears around the lake, and deltas form at the mouths of rivers, but individual irregularities in the bottom of the basin still remain;

3) stage of old age - the lake is surrounded by the slopes of deltas and screes of coastal shallows; alluvial deposits are widespread and line the lake basin;

4) the stage of extinction and death, when the lake becomes so shallow that the central bottom plain is located.

almost level with the coastal shallows and turns into them (there are no talus slopes anymore). Aquatic vegetation spreads everywhere, passes from underwater to above-water (swamp), and the lake turns into a swamp.

Lake bottom population

A lake is a water-filled basin or depression on the earth's surface that is not connected to the sea.

The main habitats of organisms in lakes include: benthal, or lake bottom; pelagic, or lake water column; the surface of water or, more precisely, the region of interface between water and atmosphere to which a surface tension film is associated.

The collection of benthic organisms is called benthos: among them, organisms characteristic of solid substrates are distinguished in periphyton. or will dig up. The bottom of the lake, depending on the depth, is also divided into the littoral, or coastal region, and the profundal, or deep-sea region, sometimes a transitional sublittoral strip is distinguished between them.

The pelagic zone is inhabited by two groups of organisms: one of them is capable of active movement over long distances - these are nekton (fish); Another group spends its life in suspension, passively carried away by the movements of water - this is plankton.

Plankton is dominated by very small plants and animals, because The smaller they are, the easier it is for them to remain in suspension. Organizations living in the area where water and atmosphere separate are called Neuston.

Zooplankton lake:

1) Rotifers, i.e.

microplankton component (their body is measured in fractions of a millimeter); Rotifers swim by rotating around the axis of the body using a circular row of cilia located at the anterior end.

2) protozoa,

3) cladocerans, or cladocerans;

4) copepods, or copepods. Copepods and cladocerans move in leaps, hitting the water with their front filamentous (copepods) or branched (cladoceran) antennae.

Lake bottom population:

Insect larvae (chironomids, i.e.

bell mosquito larvae; caddisfly larvae; larvae of dragonflies, stoneflies, mayflies),

Worms (ciliated worms (turbellaria)), nematodes (roundworms); leeches; oligochaetes, or small-chaete worms.

Hydracarines (water mites),

Pond mollusks (limnea, galba, radix),

Crustaceans: ostracods (barnacle crustaceans), cladocerans (cladocerans), copepods (copepods), isopods (isopods), scheopods (splitpods) and amphipods (amphipods).

There are lakes with the so-called double or even triple bottom. Their distinctive features are powerful underwater currents, numerous caves, cavities and voids at depth, as well as a high content of silt on the underwater surface.

There are not very many such lakes on the planet, it is believed that there are only a few dozen, but they are the most famous. It is the depth of such lakes that is not precisely known (as a rule, only the distance to the upper bottom is known).

It is believed that double-bottom lakes are usually formed on the site of peat bogs.

The bottom of such reservoirs is a mixture of sand, pebbles and peat. Along the shore, where reeds and sedge grow, silt deposits form. One of the specific features of lakes with a double (or even triple) bottom is that underground sources constantly penetrate into the reservoir, which is why it takes a long time to warm up.

Well, as always, they generate around them a lot of secrets, riddles and fables. All wonders are present, from aliens, Aryans and the Tunguska meteorite, to the gold of the Reich, the Amber Room and Kitezh-grad.

For each of these lakes you can create a separate topic worthy of REN TV.

A double bottom is known at Lake Balaton in Hungary. Perhaps this is where the legend about the bottomless lake came from. No one has ever reached the real bottom of this lake. All attempts were unsuccessful.

The second bottom is formed by tree trunks and sediments - silt, and divers cannot break through it. The Syr Darya River also has a double bottom in some places. But there it is formed by a layer of waterproof clay.

The Austrian lake Toplitz has two names - Toplitz See and Toplitz.

This is a lake with a “double bottom”. At a depth of 4-5 meters, underwater islands float in it. They are accumulations of unsunken logs.

Differences between lakes based on the origin of the basins, examples of placement

Shaitan Lake, which is not far from Okunevo, has a double bottom, and even horses often refuse to approach the lake, because although the water is clear and the bottom seems to be clearly visible, in fact, if you step on it, it is easy to fall into the depths.

Lake Inyshko in the Chelyabinsk region has a double (or maybe triple) bottom - the top one consists of peat, the second bottom is made of silt and sand. In some places, depth measurements simply did not give results, as if there was no bottom at all. Local residents say that it was here that barrels of gold were buried, and not by anyone, but by Emelyan Pugachev himself.

According to a number of reports, the nearby Lake Turgoyak also has a double (triple) bottom.

Vorozheska is also a lake with a double bottom. Vorozheska lies on the slopes of the Svidovets ridge, in a basin at an altitude of 1460m above sea level. Consists of two small reservoirs connected by a stream. A special feature of Vorozheski is that only the lower, small lake is visible from the ridge. And only after going down a steep, barely noticeable path, you can see both lakes and the snowfield, where the stream that feeds Vorozheska originates.

Lake Zerkalnoe (Leningrad region, Vyborg district, Semiozerye village) is one of the deepest lakes with a double bottom. The lake goes in layers - first there is water, then a layer of silt and again water, then a hard bottom. Divers are afraid to swim here, the water is dark and when you get out of the water, you are often covered in black mucus.

But still, the surface of the water reflects light like a mirror - hence the name. When you try to lower a weight on a fishing line (in the center of the lake, from the ice), the fishing line goes sixty meters deep.

It is believed that Lake Svetloyar near the village of Vladimirsky, Voskresensky district, also has a double bottom, under the water there is a “cloud” of organic sediments, very soft, and then there is a real hard bottom, which is very difficult to reach.

The beautiful Lake Pleshcheyevo, on which the ancient Russian city of Pereslavl-Zalessky stands, also has a double bottom.
Research was carried out here back in the 50s of the 20th century. Karst formations and underground caves were discovered at the bottom. And it was here that a unique lobe-finned fish called coelacanth was caught.

A century ago it was declared completely extinct. And later she was found alive near African waters.

On the slope of Karymskaya Sopka, in Kamchatka, there is also a lake with a double bottom. The fact is that the natural or original bottom of this lake constantly throws out powerful fountains of gas, which carry with them many small grains of sand.

It is these grains of sand that create a dense top layer, along which, like a bridge, you can wade across this rather deep lake.

Lake Baikal, the namesake of Great Baikal, is located one and a half kilometers from the Lesosibirsk-Yeniseisk highway. We tried to check its depth. It turned out that the lake has a double bottom. At a depth of 3.5 meters, silted driftwood lay as a continuous flooring.

Having pulled it apart, the scuba divers discovered the second bottom. But already at a depth of more than 10 meters!

Flowing - through which the transit flow of the river passes (Lake Chudskoye, Sarezskoye).

The concept of “lake” includes a basin and the water mass that fills it as an inextricable whole.

The origin of the lake is associated with the formation of a basin under the influence of endogenous and exogenous processes and its filling with water for a long time.

Lakes, their origin, distribution by territory

Tectonic

Volcanic

3. Glacial

They are divided into:

trogous

carriage and circus(Alps, Caucasus)

moraine(northern Russia, USA, Canada)

supraglacial in the languages of glaciers (Caucasus, Lake Como in the Alps)

4. Karst

Meteorite

6. Thermokarst

7. Suffosion— formed in subsidence during mechanical washing out of fine soils (Western Siberia - Lake

8. River

9. Landslide-dammed

Marine

Aeolian

12. Organogenic

very big

big-101-1000 km2 (Ilmen);

average— 10-100 km2;

small- less than 10 km2.

Article: Types of lakes based on the origin of lake basins.

ORIGIN AND TYPES OF LAKE DEPOSITS.

Lake depressions can be of exogenous and endogenous origin. Both of them, in turn, are divided into dam and basin.

Dam depressions of exogenous origin are widely developed.

An example of them is Lake Sarez in the Pamirs, formed in 1911 as a result of the collapse of the Rocky massif on the right bank of the river. Bartang. During this collapse, a dam 5 km long and 700 m high appeared in the river gorge. The river overflowed and formed a lake, flooding the Sarez village located above the dam. Hence the lake received the name Sarez. The filling of the lake continued for several years. The length of this lake is 85 km and the depth at the dam is about 0.5 km.
In the mountains, cases of lakes appearing as a result of the damming of rivers by the terminal moraine shafts of retreating glaciers are very common.
Currently, many artificial lakes - reservoirs - are being created during the construction of dams on rivers for irrigation purposes, as well as to generate electricity and regulate the flow of water in rivers that become shallow during low-water periods.

An example of such lakes are those created and being created in the river basin. Volga Moscow Sea, Kuibyshev Reservoir, Stalingrad Reservoir, Tsimlyanskoye on the river. Don, a number of reservoirs on the river. Dnieper, Angara, etc., as well as numerous artificial dam lakes and ponds on many smaller rivers.
Basin depressions exogenous origin are diverse in their origin.

The most common basins are those associated with glacial activity and karst manifestations.
In the north-west of the European part of the USSR there are many lakes that arose as a result of the activity of continental ice during the Quaternary period. In Karelia and bordering Finland there are numerous lake depressions, plowed by ice in the thickness of Precambrian metamorphic rocks.

To a large extent, the depressions of Lakes Onega and Lake Ladoga were created in this way. To the south of the Gulf of Finland, to the latitude of the hills located north of the cities of Minsk, Orsha, and Smolensk, stretches a vast region called the Lake District. The lakes concentrated here have a different origin than the lakes of Karelia and Finland. Their occurrence is due to the uneven accumulation of moraine sediments, which led to the formation of depressions in the relief, filled with water in a humid climate.
Another type of basin lakes of exogenous origin are lakes that fill karst funnels and sinkholes.

Failure lakes are especially typical in areas of shallow occurrence of readily soluble halide, sulfate and carbonate rocks.
Groundwater, dissolving salt deposits, forms cavities, the arches of which turn out to be unstable and collapse. In the surface depressions formed in this way, water accumulates due to meteoric and groundwater. The lakes of the Northern Caspian region - Inderskoye, Baskunchak, Elton, Chelkar, etc. - have this origin.

As a rule, the size of karst lakes is very small.
Small lakes are also common in underground karst caves. For example, in the famous Kungur cave in the Urals, up to 36 lakes are known.
Basin lake depressions of endogenous origin are also very common. Such depressions are: Baikal, the bottom of which is lowered along fault cracks to a depth of 1741 m; the Dead Sea depression and a number of lakes in Africa (Nyassa, Tanganyika, Rudolf, etc.).
The formation of lakes in the craters of extinct volcanoes and in volcanic explosion pipes is associated with endogenous processes.

Lakes of this origin are called maars.
Dam depressions of endogenous origin are formed less frequently. A similar example is the lake formed on the river. Bol. Uzen, flowing from General Syrt to the Caspian lowland. For most of its length, the river does not have a channel watercourse during low-water periods. Only in some reaches a little water is retained and reeds grow. About 9 km below the village. In the Aleksandrov-Gai riverbed a continuous stretch of water appears in the form of a narrow lake 90 km long, stretching to the village.

Furmanov, where its maximum depth reaches 18 m. Drilling operations for oil gas in the valley of the river. Bol. Uzen, slightly below the village. Furmanov, a salt dome was discovered, that is, an underground uplift of rock layers. This dome blocked the river bed. Bol. Uzen, as a result of which the above-described natural reservoir arose.

Lakes: characteristics and types

Two to three kilometers below this tectonic dam, the river bed becomes dry again.
Lakes also differ in their hydrological regime. These differences are mainly due to climatic conditions. Exist lakes with humid (wet) and arid (arid and desert) climates.
Among the lakes of a humid climate, there are flowing, periodically flowing and stagnant lakes, which, however, always have underground flow through groundwater.

Lakes of arid type are divided into periodically drainage and drainless.
Due to the presence of surface or underground runoff, a large amount of incoming fresh water and low evaporation, lakes of the humid type are almost all fresh, without exception. In contrast, most lakes of the arid type are salty to one degree or another, sometimes the water in them is a real brine.

This is due to the fact that in arid climates, the water in the lake intensively evaporates and the concentration of salts dissolved in it gradually increases.

The origin of lakes and their distribution on the globe

A lake is a natural land body of water with slow water exchange. Lakes are classified according to the nature of water exchange:

Sewage - i.e. discharging part of their waters in the form of river flow (Baikal, Onega, Ladoga)

Drainless - i.e. devoid of drainage. Characteristic of arid regions (Issyk-Kul, Balkhash, Chad).

Flowing - through which the transit flow of the river flows (lake.

Chudskoye, Sarezskoye).

The concept of “lake” includes a basin and the water mass that fills it as an inextricable whole. The origin of the lake is associated with the formation of a basin under the influence of endogenous and exogenous processes and its filling with water for a long time.

Lakes are ubiquitous on the land surface.

There are especially many lakes in areas of ancient glaciation and permafrost (northern Europe, USA, Canada, Siberia).

176 thousand are concentrated in lakes around the world.

km3 of water, including 91 thousand km3 of fresh water. On the globe, lakes occupy 2.1 million km2, i.e. 1.4% sushi.

The largest lakes (by area) include: Caspian brackish Sea - 374,000 km2 (78,200 km3 of water), Verkhneye - 82,680 km2 (Canada), Victoria - 69,000 km2 (Tanzania), Aral Sea - 64,100 km2 (Kazakhstan), Huron - 59,800 km2 (Canada, USA), Michigan - 58,100 km2 (USA) Tanganyika - 32,900 km2 (Tanzania, Zaire).

Baikal is 31,500 km2, and its volume is 23,000 km3 - the largest volume of fresh water and the deepest in the world (1620m).

The best known typology of lakes is based on the nature of the origin of lake basins.

The following types of lakes are distinguished:

1. Tectonic- formed in troughs of the earth's crust on the plains (Ladoga, Onega), in mountain troughs (Issyk-Kul, Balkhash), in rifts, grabens (Baikal, Tanganyika).

2. Volcanic— formed in craters, calderas of volcanoes (lakes of Java), in depressions of lava covers (lakes of Kamchatka, Lake Kivu in Africa).

3. Glacial— formed in relief depressions formed by the exaration and accumulative activity of cover and mountain glaciers.

They are divided into:

trogous— (Lake Geneva, Karelia, Scandinavia)

carriage and circus(Alps, Caucasus)

moraine(northern Russia, USA, Canada)

supraglacial in the languages of glaciers (Caucasus, lake.

What are the different origins of lakes and what are their differences?

Como in the Alps)

4. Karst- formed in negative forms of relief associated with the dissolving activity of waters (Crimea, Caucasus - Ritsa)

5. Meteorite— formed as a result of the impact of cosmic bodies (Lake Kaali in Estonia)

6. Thermokarst— formed in the active layer of permafrost (tundra, forest-tundra, northern taiga)

7. Suffosion— formed in subsidence during mechanical leaching of fine soils (Zap.

Siberia - lake Chany)

8. River— formed as a result of water-erosion and water-accumulative activity of permanent watercourses. These include: oxbow lakes, reservoir, delta, and valley reservoirs.

Landslide-dammed– formed in the mountains as a result of blocking of river valleys by landslide bodies (Sarez in the Pamirs, Amtkeli in the Caucasus)

10. Marine— formed as a result of the separation of parts of bays, bays, and estuaries from the sea water area by sandy deposits. There are estuary lakes (flooded river valleys) and lagoon lakes (areas of water separated from the sea by bars and spits).

Aeolian- formed in blowout basins and between dunes (Lake Teke in Kazakhstan).

12. Organogenic— intramarsh lakes and lake-lagoons inside atolls.

Lakes can also be classified by size:

very big— with an area of more than 1000 km2 (Balkhash, Baikal);

There are many bodies of water, including lakes, on the territory of the Russian Federation. The largest of them are: Lake Baikal, Lake Ladoga, Lake Onega, Lake Peipsi, Lake Ilmen, Lake Khantaiskoe, Segozero, Lake Kulunda and Lake Teletskoe. There are many bodies of water, including lakes, on the territory of the Russian Federation. The largest of them are: Lake Baikal, Lake Ladoga, Lake Onega, Lake Peipsi, Lake Ilmen, Lake Khantaiskoe, Segozero, Lake Kulunda and Lake Teletskoe.

Tectonic (formed in faults, cracks in the earth's crust) Tectonic (formed in faults, cracks in the earth's crust) Glacial (the work of an ancient glacier) Glacial (the work of an ancient glacier) Volcanic (located in the craters of volcanoes). Volcanic (located in the craters of volcanoes). Oxbow lakes (old river beds) Oxbow lakes (old river beds) Karst (dissolving) Karst (dissolving) Lakes also differ in origin:

The deepest lake on Earth. Maximum depth 1620 m. Mirror area The deepest lake on Earth. The greatest depth is 1620 m. The area of the mirror is 31.5 thousand km2. The height above sea level is 456 m. 31.5 thousand km2. The height above sea level is 456 m. It is the heritage of the Earth. Is the heritage of the Earth. Length more than 600 km, maximum width about 80 kilometers Length more than 600 km, maximum width about 80 kilometers

The meaning of lakes. The lake changes the microclimate of the environment. The lake changes the microclimate of the environment. Contribute to raising the groundwater level Contribute to raising the groundwater level Lakes turn into swamps in which peat accumulates. Lakes turn into swamps in which peat accumulates. Salts accumulate in salt lakes. Salts accumulate in salt lakes. Lakes change their topography: waves destroy the shores. Lakes change their topography: waves destroy the shores. Sedimentary deposits (silt, sand, clay.) accumulate at the bottom. Sedimentary deposits (silt, sand, clay.) accumulate at the bottom.

Use of lakes. Lakes are colossal reserves of fresh water. Lakes are colossal reserves of fresh water. Sources of fish resources, game animals, mineral raw materials. Sources of fish resources, game animals, mineral raw materials. The lake coast is a favorable area not only for life, but also for recreation and restoration of health. The lake coast is a favorable area not only for life, but also for recreation and restoration of health.

How are lakes currently used? Unfortunately, not only for the water supply of cities and villages, but also for the discharge of dirty wastewater. Let's think: a person - a rational being - takes water from the lake for drinking - takes water from the lake for drinking and dumps wastewater into it. Is this reasonable?

A lake is an enclosed depression of land filled with water. It has a slow water exchange, unlike rivers, and does not flow into the waters of the oceans, unlike the seas. These bodies of water are unevenly distributed on our planet. The total area of the Earth's lakes is about 2.7 million km 2, or about 1.8% of the land surface.

The lakes have a number of differences among themselves, both in external parameters and in the composition of the water structure, origin, etc.

Classification of lakes by origin

Glacial reservoirs were formed due to the melting of glaciers. This happened during periods of severe cold spells that shackled the continents repeatedly over the past 2 million years. The result of the ice ages were modern lakes located in North America and Europe, namely in Canada, Baffin Island, Scandinavia, Karelia, the Baltic states, the Urals and other places.

Huge blocks of ice, under the weight of their weight, and also due to their movements, formed considerable pits in the thickness of the earth's surface, sometimes even pushing tectonic plates apart. In these pits and faults, after the melting of the ice, reservoirs were formed. One of the representatives of glacial lakes can be called lake. Arbersee.

The reason for the occurrence was the movement of lithospheric plates, as a result of which faults formed in the earth's crust. They began to fill with water from melting glaciers, which led to the appearance of this type of reservoir. The clearest example is Lake Baikal.

River lakes appear when some sections of flowing rivers dry out. In this case, the formation of chain reservoirs arising from one river takes place. The second option for river formations are floodplain lakes, which appear due to water barriers that interrupt the water channel.

Coastal lakes are called estuaries. They appear when lowland rivers are flooded by sea waters or as a result of the subsidence of sea coasts. In the latter case, a strip of land or shallow water appears between the newly formed bay and the sea. In the estuaries that emerged from the confluence of the river and the sea, the water has a somewhat salty taste.

Karst lakes are earthen pits that are filled with the waters of underground rivers. Pits are depressions in the lithosphere consisting of limestone rocks. As a result of the failure, the bottom of the reservoir is lined, which affects the transparency of the waters it fills: they are crystal clear.

Karst lakes have one distinctive feature - they appear periodically. That is, they can disappear and form again. This phenomenon depends on the level of underground rivers.

They are located in mountain basins. They are formed in several ways. Due to mountain collapses that block the river flow and thereby form lakes. The second method of formation is the slow descent of huge blocks of ice, which leave behind deep land depressions - basins that are filled with water from melting ice.

Volcanic lakes appear in the craters of dormant volcanoes. Such craters have significant depth and high edges, which impedes the flow and inflow of river water. This makes the volcanic lake virtually isolated. The craters are filled with rainwater. The specific location of such objects is often reflected in the composition of their waters. High levels of carbon dioxide make them dead and unsuitable for life.

These are reservoirs and ponds. They are created intentionally for industrial purposes in populated areas. Also, artificial lakes can result from excavation work, when the remaining excavation pits are filled with rainwater.

Above, a classification of lakes was compiled depending on their origin.

Types of lakes by location

A classification of lakes depending on their position in relation to the earth can be made as follows:

Land lakes are located directly on the land surface. These participate in the constant water cycle.
Underground lakes are located in underground mountain caves.

Classification by mineralization

You can classify lakes according to the amount of salts as follows:

Fresh lakes are formed from rainwater, melting glaciers, and groundwater. The waters of such natural objects do not contain salts. In addition, fresh lakes are a consequence of the damming of river channels. The largest fresh lake is Baikal.
Salt water bodies are divided into brackish and saline.

Brackish lakes are common in arid areas: steppes and deserts.

Salt lakes resemble oceans in terms of the salt content in their water column. Sometimes the salt concentration of lakes is slightly higher than in the seas and oceans.

Classification by chemical composition

The chemical composition of the Earth's lakes is different, it depends on the amount of impurities in the water. The lakes are named based on this:

Carbonate lakes have increased concentrations of Na and Ca. Soda is extracted from the depths of such reservoirs.
Sulfate lakes are considered healing due to their Na and Mg content. In addition, sulfate lakes are where Glauber's salt is mined.
Chloride lakes are salt lakes, which are the place of production of the usual table salt.

Classification by water balance

Sewage lakes are equipped with the help of which a certain amount of water is discharged. As a rule, such reservoirs have several rivers flowing into their basin, but there is always only one flowing out. An excellent example is the large lakes - Baikal and Teletskoye. The water of sewage lakes is fresh.
Endorheic lakes are salt lakes, since the flow of water in them is more active than its inflow. They are located in desert and steppe zones. Sometimes they produce salt and soda on an industrial scale.

Classification by amount of nutrients

Oligotrophic lakes contain relatively small amounts of nutrients. The features are the transparency and purity of the waters, the color from blue to green, the depth of the lakes is significant - from medium to deep, the decrease in oxygen concentration closer to the bottom of the lake.
Eutrophic ones are saturated with a high concentration of nutrients. The peculiarities of such lakes are the following phenomena: the amount of oxygen sharply decreases towards the bottom, mineral salts are contained in excess, the color of the water is from dark green to brown, which is why the transparency of the water is low.
Dystrophic lakes are extremely poor in minerals. There is little oxygen, transparency is low, the color of the water can be yellow or dark red.

Conclusion

The Earth's water basin consists of: rivers, seas, oceans, glaciers of the world's oceans, lakes. There are several types of lake classifications. They were discussed in this article.

Lakes, like other bodies of water, are the most important natural resources that are actively used by humans in various fields.