What is a lake in geography. List, names, descriptions, maps and photos of the largest lakes in Russia. Lakes, their origin, distribution by territory

A lake is a closed depression of land that collects and accumulates surface and underground water. Unlike rivers, these are reservoirs of slow water exchange. total area of all lakes on Earth is 2.7 million square kilometers. They occupy about 1.8% of the land surface.

Lakes are always and everywhere formed according to one scenario - a depression, lowland or fault - a basin - is formed in the area for various reasons. 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).

Origin of lake basins

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. In the photo - 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 with landslides rocks. 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 of 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.

According to the water regime, there are two types of lakes - drainage and drainless. Sewage lakes are lakes in which water exchange occurs, rivers flow into them and flow 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. On the picture - 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. The 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 original state for a long time.

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On our planet there is great amount lakes They can differ strikingly from each other both in size, origin, and other indicators. Then how are they similar, and what is a lake in general?

It is not so easy to give a precise definition of this concept. For example, if we say that this is a body of water surrounded on all sides by land, then this will not be entirely correct. Since those into which rivers flow (or flow out of them) have a broken coastline.

If we say that this is a fresh body of water, then what about the Dead Sea and others in which the water is salty? We can say that they have no connection with the oceans. But known to everyone, located in South America, connects to the Caribbean Sea.

So what is a lake? It would be more correct to say that this is a body of natural origin on land. First of all, the lakes differ from each other in size. Sometimes in the mountains you can find small ones, only a few tens of meters long, while the largest lake on Earth - the Caspian Sea - has a length of more than 1000 kilometers.

Rainwater flows into lakes, rivers and streams flow into them, so they must be in low points terrain. But this is not always observed. South American Lake Titicaca is located at an altitude of 3812 meters above sea level.

How are they formed?

To understand what a lake is, you need to find out how they arise. There are glacial reservoirs located in depressions of the earth's surface, formed under the enormous weight of an ancient glacier. These depressions gradually filled with melted glacial waters. Most often they are placed in large groups, have small sizes and depths. There are many of them in Finland, Canada, and Siberia.

Located in high mountain basins. Sometimes it happens that such a lake appears right before our eyes - during mountain falls, the river bed is blocked and water accumulates near the dam that has arisen. Usually they are short-lived, and water quickly erodes the barrier, but there are exceptions. An example is the Pamirs.

The lakes formed in are elongated, narrow and very deep. There are many of them in Africa: Tanganyika, Nyasa and others. This is also the deepest lake in the world, Lake Baikal.

Reservoirs of tectonic origin can also have a shallow depth, for example, the Khmelevsky lakes, which are located in the eastern part. Four closed reservoirs are filled; not a single stream flows into them and does not flow out either.

High mountain lakes filled with glacial water are only fresh. But the Dead Sea, located in a basin, is so salty that there is no life in it.

In some lakes, the water, due to the presence of a large number of impurities in its composition, is not only salty, but also cloudy, which gives it a different color. But most bodies of water, especially small ones, have fresh and clean water. For example, in the Leningrad region there is Lake Bezymyanny, which is considered one of the cleanest in Russia. The reason for this is the presence large number springs and springs, constantly renewing and refreshing water.

Some of the lakes regularly change their size, and their coastline is indicated conventionally on maps. Most often this depends on seasonal precipitation. Thus, Lake Chad on the African continent can change several times throughout the year.

- a body of water formed on the surface of the land in a natural depression. Since the lake does not have a direct connection with the ocean, it is a body of slow water exchange.

Total area of lakes globe- about 2.7 million km 3, which is 1.8% of the land surface.

Main characteristics of the lake:

lake area - water surface area;
length coastline - water edge length;
lake length - the shortest distance between the two most distant points on the coastline, average width - area to length ratio;
lake volume - volume of the basin filled with water;
average depth - ratio of water mass volume to area;
maximum depth - is found by direct measurements.

The largest lake on Earth by water surface area is the Caspian (376 thousand km 2 at a water level of 28 m), and the deepest is Baikal (1620 m).

The characteristics of the largest lakes in the world are given in table. 1.

Each lake has three interconnected components: basin, water mass, vegetation and animal world reservoir

Lakes of the world

By position In the lake basin, lakes are divided into above-ground and underground. The latter are sometimes filled with juvenile water. The subglacial lake in Antarctica can also be classified as an underground lake.

Lake basins could be like endogenous, so exogenous origin, which most significantly affects their size, shape, and water regime.

The largest lake basins. They can be located in tectonic depressions (Ilmen), in foothill and intermountain troughs, in grabens (Baikal, Nyasa, Tanganyika). Most large lake basins have a complex tectonic origin; both fault and fold movements are involved in their formation (Issyk-Kul, Balkhash, Victoria, etc.). All tectonic lakes are large in size, and most have significant depths and steep rocky slopes. The bottoms of many deep lakes lie below the level of the World Ocean, and the surface of the lake lies above the level. Certain patterns are observed in the location of tectonic lakes: they are concentrated along faults in the earth’s crust or in rift zones (Syrian-African, Baikal), or frame shields: along the Canadian shield are located the Great Bear Lake, the Great Slave Lake, the Great North American Lakes, along the Baltic Shield — Onega, Ladoga, etc.

Lake name	Maximum surface area, thousand km 2	Altitude above sea level, m	Maximum depth, m
Caspian Sea
				North America
Victoria
				North America
				North America
Aral Sea
Tanganyika

Nyasa (Malawi)
Big Bear				North America
Great Slave				North America
				North America

Winnipeg				North America

				North America
Ladoga
Maracaibo				South America
Bangweulu

Onega
Tonle Sap

Nicaragua				North America
Titicaca				South America
Athabasca				North America
				North America
Issyk-Kul
Bolshoye Solenoye				North America
				Australia

Volcanic lakes occupy craters and calderas extinct volcanoes(Kronopkoye Lake in Kamchatka, lakes in Java, New Zealand).

Along with lake basins created by internal processes of the Earth, there are very numerous lake baths formed due to exogenous processes.

Among them the most common glacial lakes on the plains and in the mountains, located both in basins plowed by glaciers and in depressions between hills with uneven deposition of moraine. The lakes of Karelia and Finland owe their origin to the destructive activity of ancient glaciers, which are elongated in the direction of glacier movement from northwest to southeast along tectonic cracks. In fact, Ladoga, Onega and other lakes have a mixed glacial-tectonic origin. Glacial basins in the mountains include numerous, but small carts lakes located in bowl-shaped depressions on mountain slopes below the snow line (in the Alps, Caucasus, Altai), and trogous lakes - in trough-shaped glacial valleys in the mountains.

The uneven accumulation of glacial deposits on the plains is associated with lakes among hilly and moraine terrain: in the north-west of the East European Plain, especially in the Valdai Upland, in the Baltic states, Poland, Germany, Canada and the northern USA. These lakes are usually shallow, wide, with lobed shores, with islands (Seliger, Valdai, etc.). In the mountains, such lakes arose on the site of former glacier tongues (Como, Garda, Würm in the Alps). In areas of ancient glaciations, there are numerous lakes in the hollows of the runoff of melted glacial waters; they are elongated, trough-shaped, usually small and shallow (for example, Dolgoe, Krugloe - near Moscow).

Karst lakes are formed in places where rocks are leached by underground and partly surface waters. They are deep, but small, often round in shape (in the Crimea, the Caucasus, the Dinaric and other mountainous areas).

Suffosion lakes are formed in basins of subsidence origin at the site of intensive removal of fine earth and mineral particles by groundwater (southern Western Siberia).

Thermokarst Lakes appear when permafrost soil melts or ice melts. Thanks to them, the Kolyma Lowland is one of the most lake regions in Russia. Many relict thermokarst lake basins are located in the north-west of the East European Plain in the former periglacial zone.

Aeolian lakes arise in blowing basins (Lake Teke in Kazakhstan).

Zaprudnye lakes are formed in the mountains, often after earthquakes, as a result of landslides and landslides blocking river valleys (Lake Sarez in the Murghab valley in the Pamirs).

In the valleys of lowland rivers, the most numerous are floodplain oxbow lakes of a characteristic horseshoe shape, formed as a result of meandering of rivers and subsequent straightening of channels; when rivers dry up, river lakes are formed in bochagas - reaches; in river deltas there are small ilmen lakes, in place of channels, often overgrown with reeds and reeds (ilmen lakes of the Volga delta, lakes of the Kuban flood plains).

On the low-lying coasts of the seas, coastal lakes are typical in place of estuaries and lagoons, if the latter are separated from the sea by sandy alluvial bridges: spits, bars.

A special type is organogenic lakes among swamps and coral buildings.

These are the main genetic types of lake basins, determined by natural processes. Their location on the continents is presented in Table. 2. But recently, more and more “man-made” lakes created by man have appeared - so-called anthropogenic lakes: lakes - reservoirs on rivers, lakes - ponds in quarries, in salt mines, on the site of peat mining.

By genesis of water masses There are two types of lakes. Some have water of atmospheric origin: precipitation, river and groundwater. Such lakes fresh, although in dry climates they may eventually become salty.

Other lakes were part of the World Ocean - these are relict salty lakes (Caspian, Aral). But even in such lakes, primary sea water can be greatly transformed and even completely displaced and replaced by atmospheric waters (Ladozhskoye, etc.).

Table 2. Distribution of the main genetic groups of lakes by continent and part of the world

Genetic groups of lakes	Continents and parts of the world
Genetic groups of lakes	Western Europe	Foreign Asia	North America	South America	Australia
Glacial
Glacial-tectonic
Tectonic
Volcanic
Karst
Residual
Lagoon
Floodplain

Depending from water balance, t.s. According to the conditions of inflow and outflow, lakes are divided into drainage and drainageless. Lakes that discharge part of their waters in the form of river runoff - sewage; a special case of them are flowing lakes. Many rivers can flow into the lake, but only one flows out (the Angara from Lake Baikal, the Neva from Lake Ladoga and etc.). Lakes that do not drain into the World Ocean - drainless(Caspian, Aral, Bolshoye Solenoye). The water level in such lakes is subject to fluctuations of varying duration, which is primarily due to long-term and seasonal climate changes. At the same time, the morphometric characteristics of lakes and the properties of water masses change. This is especially noticeable on lakes in arid regions, which promise long cycles of climate moisture and aridity.

Lake waters like others natural waters, are characterized by different chemical composition and varying degrees of mineralization.

Based on the composition of salts in the water, lakes are divided into three types: carbonate, sulfate, and chloride.

By degree of mineralization lakes are divided into fresh(less than 1%o), brackish(1-24.7%c), salty(24.7-47%o) and mineral(more than 47%c). An example of a fresh lake is Baikal, the salinity of which is 0.1%, brackish - Caspian sea water - 12-13%, Bolshoye Solenoye - 137-300%, Dead Sea - 260-270%, in some years - up to 310%c.

The distribution of lakes with varying degrees of mineralization on the earth's surface shows geographic zonality, determined by the moisture coefficient. In addition, those lakes into which rivers flow are characterized by low salinity.

However, the degree of mineralization can vary within the same lake. For example, in the closed lake Balkhash, located in an arid zone, in the western part, where the river flows. Or, the water is fresh, but in the eastern part, which is connected to the western part only by a narrow (4 km) shallow strait, the water is brackish.

When lakes become oversaturated, salts begin to precipitate from the brine and crystallize. Such mineral lakes are called self-planting(for example, Elton, Baskunchak). Mineral Lakes, in which lamellar fine needles are deposited, are known as mud.

Plays an important role in the life of lakes thermal regime.

Freshwater lakes in the hot thermal zone are characterized by the warmest water at the surface, which gradually decreases with depth. This temperature distribution over depth is called direct thermal stratification. Lakes in the cold thermal zone have the coldest (about 0 °C) and lightest water at the top almost all year round; With depth, the water temperature increases (up to 4°C), the water becomes denser and heavier. This temperature distribution over depth is called reverse thermal stratification. Lakes in the temperate thermal zone have variable stratification by season: direct in summer, reverse in winter. In spring and autumn there come moments when the vertical temperature is the same (4 °C) at different depths. The phenomenon of constant temperature over depth is called homothermy(spring and autumn).

The annual thermal cycle in temperate lakes is divided into four periods: spring heating (from 0 to 4 °C) is due to convective mixing; summer heating (from 4 °C to maximum temperature) - by molecular thermal conductivity; autumn cooling (from maximum temperature to 4 °C) - by convective mixing; winter cooling (from 4 to 0 °C) - again by molecular thermal conductivity.

IN winter period Freezing lakes have the same three phases as rivers: freezing, freezing, opening. The process of ice formation and melting is similar to rivers. Lakes are generally covered with ice for 2-3 weeks longer than rivers in the region. The thermal regime of freezing salt lakes resembles that of seas and oceans.

Dynamic phenomena in lakes include currents, waves and seiches. Discharge currents occur when a river flows into a lake and water flows out of the lake into the river. In flowing lakes they can be traced throughout the entire water area of the lake, in non-flowing lakes - in areas adjacent to the mouth or source of the river.

The height of the waves on the lake is less, but the steepness is greater compared to the seas and oceans.

The movement of water in lakes, along with dense convection, contributes to the mixing of water, the penetration of oxygen into the lower layers, and the uniform distribution of nutrients, which is important for very various inhabitants lakes

By nutritional properties of water mass and the conditions for the development of life, lakes are divided into three biological types: oligotrophic, eutrophic, dystrophic.

Oligotrophic- low-nutrient lakes. These are large, deep, transparent lakes with greenish-blue water, rich in oxygen, so organic residues are intensively mineralized. Due to the small amount of nutrients, they are poor in plankton. Life is not rich, but there are fish and crustaceans. These are many mountain lakes, Baikal, Geneva, etc.

Eutrophic the lakes have a high content of nutrients, especially nitrogen and phosphorus compounds, are shallow (up to 1015 m), well heated, with brownish-green water. The oxygen content decreases with depth, which is why fish and other animals die in winter. The bottom is peaty or muddy with an abundance of organic residues. In summer there is a “blooming” of water due to the strong development of phytoplankton. The lakes have a rich flora and fauna. They are most common in forest-steppe and steppe zones.

Dystrophic the lakes are poor in nutrients and oxygen and are shallow. The water in them is acidic, slightly transparent, and brown due to the abundance of humic acids. The bottom is peaty, there is little phytoplankton and higher aquatic vegetation, as well as animals. These lakes are common in heavily swampy areas.

In the last decade, due to the increased supply of phosphorus and nitrogen compounds from fields, as well as the discharge of wastewater from some industrial enterprises, eutrophication of lakes has been observed. The first sign of this unfavorable phenomenon is a strong bloom of blue-green algae, then the amount of oxygen in the reservoir decreases, silt forms, and hydrogen sulfide appears. All this will create unfavorable living conditions for fish, waterfowl, etc.

Evolution of lakes occurs in different ways in humid and dry climates: in the first case, they gradually turn into swamps, in the second - into salt marshes.

In a humid (humid) climate, the leading role in filling the lake and turning it into a swamp belongs to vegetation, partly to the remains of the animal population, which together form organic remains. Temporary streams and rivers bring mineral deposits. Small lakes with gentle shores are overgrown by pushing vegetation ecological zones from the periphery to the center. Eventually the lake becomes a grassy, low-lying marsh.

Deep lakes with steep banks overgrow differently: by growing from above alloys(swell) - a layer of living and dead plants. It is based on plants with long rhizomes (cinquefoil, cinquefoil, whitewing), and other herbaceous plants and even shrubs (alder, willow) settle on the network of rhizomes. The float first appears on the shores, protected from the wind, where there is no waves, and gradually advances onto the lake, increasing in power. Some plants die and fall to the bottom, forming peat. Gradually, only “windows” of water remain in the ravine, and then they disappear, although the basin is not yet filled with sediments, and only over time the raft closes with the peat layer.

In dry climates, lakes eventually become salt marshes. This is facilitated by an insignificant amount of precipitation, intense evaporation, a decrease in the influx of river water, and the deposition of solid sediments brought by rivers and dust storms. As a result, the water mass of the lake decreases, the level decreases, the area decreases, the concentration of salts increases, and even a fresh lake can first turn into a salt lake (Great Salt Lake in North America), and then into the salt marsh.

Lakes, especially large ones, have a softening effect on the climate of the surrounding areas: they are warmer in winter and cooler in summer. Thus, at coastal weather stations near Lake Baikal the temperature in winter is 8-10 °C higher, and in summer by 6-8 °C lower than at stations outside the influence of the lake. Air humidity near the lake is higher due to increased evaporation.

Lakes are always and everywhere formed according to the same 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 are 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.

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.

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.

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.

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

Mineral Lakes

Based on salinity, lakes are classified 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.

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, the glacier “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) existing 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 arms) - in deltas 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. Basins small sizes, shallow (between dunes and dunes in the Aral-Caspian lowland).

Dammed (dammed) lakes - arise when river valleys are blocked by mountain falls, 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 are many fresh waters, and in arid areas there are few lakes, 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 of 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 (marsh), and the lake turns into a swamp.

Lake bottom population

A lake is a water-filled basin or depression of the earth's surface that has no connection with 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 that live 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 has a double (or maybe triple) bottom. Chelyabinsk region— the top 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. Locals they 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, Lake Turgoyak, located nearby, 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 Zerkalnoye (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 were found at the bottom, underground caves. 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 cross this quite deep lake ford

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

Meteoric

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 village of Sarez 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 emerging 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 activities continental ice in 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. South of Gulf of Finland to the latitude of the hills located north of the cities of Minsk, Orsha, Smolensk, a vast region, called the Lake District, extends. 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.
Not uncommon small lakes and in underground karst caves. For example, in the famous Kungur cave Up to 36 lakes are known in the Urals.
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; depressions Dead Sea 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. Meteoric— 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);

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 one big lake does not communicate with 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. Big variety glacial processes create closed basins. Subspecies – karids.
On the world map, something similar can be found in Antarctica - Lake Vostok.
Floodplain– form where sediment from the inflow blocks main river.
Estuary lakes Sea of Azov. 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.
Meteoric– 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 shows short description 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.

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