§ 47. Lake (textbook)

§  47. Lake


What lake do you think is different from the river?


What is the lake. On land there are many depressions (Cavities) of different origin, flowing surface water and groundwater. If Penetration of water coming in than during the same time evaporates water accumulates and forms lake. Lake from the river is different because the water has not flowing like a river in the channel. Unlike sea lake is not part of the oceans.

Lakes are extremely diverse. There are lakes, seas and lake-puddles. Lake depth varies from a few centimeters to over 1.5 km! Some fresh water lakes, in others - salty. There are lakes, icebound for hundreds of years, and, conversely, a lake of hot water. Some lakes are many organisms, others are "water the desert." The largest lake on Earth is Caspian Sea. It 4 times more than white and 3 times on the Adriatic Sea. With the huge size and water similar in composition to sea salts, it is called the sea. The deepest lake globe - Baikal (1620 m). The lake is much deeper for the Barents and Kara Sea. The deepest lake in Ukraine - Svitiazke (58 m), it is 4 times Deeper in the Sea of Azov.


Fig. Lake Baikal


Formation of the lake basin. Dimensions, the contours of the coast, depth of the lake due to the origin lake basin.

Depression tectonic origin formed in result of movements of the crust. At slow lowering of large areas have depression Caspian and Aral seas, lakes. In result of deep cracks and areas rozsuvannya crust formed lake Baikal. In similar tectonic cracks formed abyss Tanganyikain Africa and Great Lakes in North America. These lakes are elongated form, large depth and high steep banks.

Volcanic lake are extinct volcanic craters. They are quite deep (100 meters), but small area. Zahatni Lake resulting collapse of rocks that partitions bed rivers. Zahatne origin is hollow lake Synevyr in the Ukrainian Carpathians.  Ice Lake are hollow, vyorani ancient and modern glaciers. They common in northern Eurasia and North America in the high mountains. Such lakes small and shallow. Floodplain lakeoccur in river valleys. They are remnants of the old bed of the former, because called lake-old women. They checked out, winding, small in area and shallow. Lymanne Lake formed because of separation from the sea mouth parts of the River sand spits. Such Lake elongated shape, shallow common in southern Ukraine on the Black and Azov Seas.



Interesting geography

Beast Lake Loch nes

Glacial lake Loch nesThat in Scotland, is known for its size or depth. It became most famous through Nessie- Ancient reptiles,  that lived on Earth 100 million years ago and which allegedlyseen in the lake today. In search of ancient animals sporyadzhayutsya submarines and surface forwarding, but Nessie from them "Escapes."


Sewage and closed lakes. Lakes, like rivers, fed by precipitation, groundwater and surface, flowing down to them (especially the all rivers). The timing of lake water evaporation and flows in as rivers. The water level in lakes, as in rivers can vary due climate change. Significant level fluctuations affect their area. In wet season it is growing, dry - is reduced. Not accidentally coastal lines of individual lakes, located in deserts, on maps dotted line. These lakes - like rubber, their sizes can be changed several times short time.

Lakes, of which flow rivers, called waste. For example, waste is Baikal - From the Angara river flows. Lakes, with where the river does not flow, called endorheic. For example, Caspian Sea-Lake does not run any river.

From river and groundwater in the lake comes salt. If salinity is not than 1 ‰, then the lake - unleavened bread. Fresh water lake is the waste because salt taken out of these rivers, which flow from him. If a closed lake, salt piled in it, the water gradually zasolyuyetsya. Salt Lakeplaced in areas with hot and dry climate. There are great evaporation from the surface of lakes, which leads to a strong saturation of water salts. Sometimes so much that they fall to the bottom as sludge. Naysolonishym Lake world is Dead sea. Its salinity reached 400 ‰. Sometimes the river Jordanthe Dead Sea fish swims. She dies within a minute. Fish is firm, as a stick pokryvshys strong salty shell. In this lake can not drowning, the man kept on the water as the float on the water.


Interesting geography

Transmogrification lake-traveler

Lake Lop NurThat in Central Asia, often changes not only shape but also location. Amazing ability lake travel " distance of 100 km because it lies in the desert and fed waters of several rivers. Depending on what the river fills the lake, and there it finds itself. Time Lop Nur splits into several lakes, or even completely dry.


Distribution of lakes and their importance. Lakes on Earth a huge number and they are everywhere. Even in the icy shell bound Antarctica is not deprived of the lakes. But in areas with humid climates are more of them than there, where the climate is dry. Most lake is mainland North America. In northern Eurasia lakes in places so much that is difficult to determine what more there - land or water. Most lake countries are Finland and Sweden. They are sometimes called "states one thousand lakes. In these areas falls a great amount of precipitation, evaporation and slight many natural cavities.

Lake - The glory of nature. Always please the eye with blue water and white water lilies in it! Shores Lakes are fine places. Lake water used for water supply and irrigation. Great Lakes in ships carrying various goods. With salt mine salt lakes, in small - raised fish.


Questions and Tasks

1. What is called a lake? What are the conditions necessary for the formation of the lake?

2. What lake is different from the sea?

3. How can the lake basin formed?

4. Why closed lake is salty?

5. Prominent geographical coordinates of Lake Baikal.

6. In nature there are many surface depressions, grooves and cuts. However, far they are not all lakes. Why?

7. Make a comparative description of two lakes (optional) for the plan:

1) name lakes and its origin;

2) physical geography;

3) area, average and maximum depth;

4) shape (round, oblong) and the nature of the coast (low, high);

5) waste or closed;

6) unleavened bread or salt;

7) origin of lake basins;

8) commercial use.