Lakes are permanently existing water bodies that are not directly connected to the world's oceans (although rivers may flow out of them and then into the ocean).
There are many lakes on our planet, they are found in all climatic zones and on all continents, including tropical deserts and Antarctica.
In Russia, there are more than 2 million lakes with an area of more than a hectare.
Spread of lakes
There are a lot of lakes in the world, but they are not evenly distributed. If we compare the distribution of lakes by continent, lakes in North America occupy the largest area as a percentage of the mainland - about 2% of the territory. Moreover, there are a lot of large lakes here - about half of the lakes with an area of more than 500 square kilometers are located in North America. But in South America and Australia lakes are not enough - only 0.3% of the area of the territory.
If we compare the countries with each other, Finland is dotted with lakes - they occupy more than 9% of the territory of this country. Finland is even called the "country of a thousand lakes", but in fact, there are more lakes - as many as 190 thousand.
Generally speaking, the lakes in the tundra and forest zone are the largest, and the more arid the climate becomes, the smaller the lakes become. Nevertheless, there are lakes in the deserts of Australia, and in the frozen, almost completely covered with ice Antarctica.
But despite the large number of lakes, the total volume of water in them is not so large - it is only 0.013% of the total amount of water on Earth.
Here are just a few of them:
- Glacial lakes are formed in the depressions created by the movement of the glacier. A large number of such lakes appeared after the end of the last glacial period 10-12 thousand years ago.
- Damp lakes are the result of blocking the valley by a natural dam (e.g. lava flow).
- Floodplain lakes are formed in the recesses of the old river channel when the river is making a new one.
- Lagoon lakes are formed as a result of the separation of sea and land areas, e.g. by sand spits, which gradually create waves.
- Karst lakes are formed by the dissolution or erosion of water-insensitive rocks, resulting in gaps in the ground.
- Volcanic lakes occur in volcanic craters.
- Meteorite lakes occur in meteor craters.
Records of lakes
The largest lake on the planet is the Caspian Sea. Its area is 371 thousand square kilometers, which is more than the area of Germany. Why is this lake called the sea? Well, first of all, it is very large, and its area is quite comparable to many real seas. Secondly, many other signs make it look like the sea. There are strong waves and storms, tides and tides in it. Finally, although today the Caspian Sea has no communication with the world ocean and is, therefore, a lake, there were times when the Caspian Sea was a real sea. About 1.5 million years ago, the Caspian Sea was connected to the Black Sea and the world ocean. By the way, the Black Sea also changed its status from time to time, becoming a lake or a sea again.
As it is known, the Volga (as well as 130 other rivers) flows into the Caspian Sea. Therefore, although the water in the Caspian Sea is not fresh, it still has three times less salinity than the world ocean. There are 50 islands in the Caspian Sea.
The deepest lake on the planet is Lake Baikal. Its maximum depth is 1642 meters. Lake Baikal is not the largest fresh lake by area. Lake Verkhneye has an area of 81 thousand square kilometers against 31 thousand square kilometers. y Baikal, but because of the large average depth of the total volume of water in Baikal is greater than in all five Great Lakes combined. Baikal is the largest lake by the volume of freshwater it contains, about 20% of the world's reserves.
Baikal is a real wonder of nature. Its water is so pure and transparent that it is close to distilled in its characteristics. Of the 2600 species of aquatic animals, more than half are unique - they are found nowhere but in Baikal.
The world's highest-altitude lake is a small lake located in the crater of the world's tallest volcano, the Ojos del Salado, in South America. It is located at an altitude of 6390 meters above sea level.
The highest lake in the world, Titicaca, is also in South America. The area of the lake is more than 8 thousand square kilometers, and it is located at an altitude of 3821 m above sea level. The lake keeps many mysteries. On the shore and the bottom of the lake ruins of ancient civilization are found out, and in the lake live some miracle there the ocean fish got there.
It is the lowest lake in the world, and at the same time, the lowest place on the planet is the Dead Sea. It is located 417 meters below sea level. It is also one of the saltiest lakes in the world - a liter of water here is about 350 grams of salt. As the name suggests, there is almost no life in the Dead Sea because of the high salinity. Nevertheless, some organisms - archaea and microscopic algae - live here.