Earth and Moon

Surface waters: Lagos

Surface waters: Lagos

The lakes they are masses of fresh or salt water that are surrounded by land.

Sometimes the lakes have been considered as miniature seas and, in fact, have some similarities.

Generally, the lakes are connected to a river system that provides them with water. There are some that are an extraordinary source of maintenance for the plant, animal and human populations of its banks. They constitute a good reserve of fresh water so that humans, since the beginning of civilization, have learned to build artificial lakes, which we call reservoirs or swamps.

LakeContinentSurface (km2)Depth (m)
Caspian SeaAsia371.0001.025
HigherNorth America82.000406
FerretNorth America60.000229
MichiganNorth America58.000281
Aral SeaAsia34.00065
Great Bear Lake North America 31.000446

Lakes characteristics

The lakes are forms of the landscape that depend on the region in which they appear and that often have a very important flora and fauna. If they occupy large areas of land they are defined as inland seas.

The lakes can be fed by one or more rivers called immissaries. For its part, the river where it drains is called emissary. If it lacks emissary, then both the lake and its basin are recognized with the term endorheic. The lakes are not usually stable structures and therefore tend to disappear. They generally receive water from rainfall, springs or tributaries.

In arid regions, where rainfall is insignificant and intense evaporation, the water level of the lakes varies according to the seasons and they become dry for long periods of time.

The lakes can be formed at any altitude and are distributed all over the world, although more than half of them are located in Canada. They are numerous in high latitudes, especially if they are also mountain areas subject to the influence of glaciers.

Types of lakes

Tectonics: They are the lakes that fill the depressions caused by failures and folding. They are lakes formed by a movement of the soil that prevents the free course of a river.

Barrier: They are formed when glacial moraines or other materials, such as volcanic lavages or landslides, plug the valleys and allow the accumulation of water and prevent its drainage.

Glaciers: Glaciers excavate large basins by polishing the bedrock and redistributing the torn materials. A glacier lake is formed when the waters occupy the hole eroded by the glacial masses.

Crater: They can occur after the explosion of the crater of a volcano, which forms a volcanic caldera or a circular sinking that can be flooded after extinction forming a lake. If the crater has no cracks and consists of low porosity materials, it can become a permanent lake if it receives enough water from the rain.

Endorheic: The lakes of endorheic basins are depressions in the earth's crust that have no exit to the sea. They contain generally somewhat salty waters, due to the progressive concentration of salts due to evaporation.

Pelagic: Pelagic lakes are nothing more than vestiges of ancient seas that were surrounded by land.

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