lake

from Wikipedia, the free encyclopedia
Lake Lucerne , Switzerland

A lake is a body of still water with or without inflow and outflow through flowing water that is completely surrounded by a land area . It represents a largely closed ecosystem .

definition

A lake is an inland body of water that represents a (larger) accumulation of water in a depression in a land area and, in contrast to an inland sea (e.g. the Mediterranean Sea), has no direct connection to the ocean on the 0 meter contour line . This means that it has no inflow and / or outflow caused by ocean currents . The inflow and outflow are usually small compared to the total amount of water in a lake. In contrast to a river, a lake has no gradient.

The term inland lake is used to distinguish inland lakes from coastal lakes (beach lakes, brackish water lakes close to the coast or lakes created by dikes along the coast), but also generally to denote lakes.

A lake in the sense of the limnological definition is usually much deeper than a pond , pond or pond , so that a temperature stratification that is stable over days to months can develop. The frequency of their mixing is used to classify the lakes, as it also has far-reaching ecological consequences (see Lake Ecosystem ). In this respect, the shallow steppe lakes such as Lake Neusiedl or Lake Balaton are not considered "real" lakes.

However, the exact demarcation between lakes and ponds / ponds etc. is fuzzy and always subjective. This is why some limnologists refer to any basin filled with water as a lake. For their categorization it would then be irrelevant whether a lake is constantly, periodically or episodically filled with water and whether it forms a permanent stratification.

Colloquially, the assignment often depends on the salinity , but this is not a criterion. A lake usually contains fresh water , but there are also large salt lakes , such as B. the Caspian Sea (therefore the earlier common name Caspisee is more appropriate ), the Aral Sea and the Dead Sea . There are also lakes containing soda , for example those in the Rift Valley in the East African Rift Valley, such as Lake Nakuru or some of the Lacken around Lake Neusiedl.

A further definition can be made via the size. The minimum size of a lake is about one hectare .

In astronomy , lakes are also used when they contain a liquid other than water, for example in the methane lakes on Titan .

Formation of lakes

Geologically and geomorphologically, a distinction is made between the following types of sea:

  • Lakes created naturally.
  • Artificial lakes. Depending on the type of installation, it is called a quarry pond or an artificial reservoir . Artificial lakes can also be created by diking sea bays, e.g. B. the IJsselmeer .

Naturally created lakes can be further subdivided according to the way they were created:

  • Glacial lakes were created by the erosive or backfilling effect of glaciers or glacier meltwater. This is the most common type of lake worldwide (e.g. the Great Lakes in North America or the numerous lakes in North and South Germany).
  • Glacier edge lakes and ice reservoirs are short-lived lakes on active glaciers.
  • Tectonic lakes were formed by the expansion of the earth's crust and the resulting cracks and rift breaks , e.g. B. Lake Baikal . A long chain of lakes formed in the East African rift valley, including Lake Tanganyika, which is 1,470 m deep . The tectonic lakes also include most of the end lakes with no drainage in arid areas , as they are usually located within subsidence areas.
  • Damming lakes are created by landslides in the mountains, by lava flows or gravel fields and on coasts by the constriction of sea bays. The latter are also known as beach lakes.
  • Karst or sinkhole lakes are created by the dissolution (and removal) of carbonate rock or salt deposits ( subrosion ) in the subsurface and subsidence of the earth's surface, for example the Arendsee and the Süße See in Saxony-Anhalt .
  • Lakes created by volcanic activity ( crater lake ). Examples in Germany are the maars in the Eifel , including Laacher See .
  • Lakes within meteorite craters such as B. the Elgygytgyn .
  • Oxygen lakes are created by the natural shifting of rivers. The old river bed then remains as an elongated lake (e.g. Kamernscher See near Havelberg ; however, due to river regulation : Alte Donau in Vienna).
  • Thermokarst lakes arise in areas with permafrost , e.g. B. in Alaska or Northern Siberia.
  • Lakes with a complex history. For example, Lake Vättern in Sweden is located . B. within a rift valley, but the basin was mainly carved out by glaciers.

Passing of lakes

Apart from the possibility that lakes can disappear as a result of rapid events, for example through the spillage of its basin or the disappearance of its dam, lakes have a typical tendency to fade away from their material balance. Tributaries bring in sediment, which gradually settles in the low-current lake. Rubble cones, avalanches and mudslides slowly coming down from mountains also contribute to the filling of a lake. Even the entry of dust, pollen, leaves and parts of plants to driftwood sinks to a large extent in the water; if material with organic carbon sinks into deep, oxygen-poor layers, it is not oxidized and decomposed, but instead is deposited as carbon-rich sludge. This process depends on the rate of entry with air currents and bank vegetation protruding over the lake. In dry areas or times, lakes without sufficient inflow can also dry out.

use

In addition to their importance for nature, natural and man-made lakes also offer a number of uses for humans.

Most of the lakes are managed by either professional or anglers . Lakes can also be used as bathing lakes for leisure and recreation , swimming and bathing . Larger lakes offer opportunities for water skiing , windsurfing, and sailing . Inland shipping is also used on many large lakes . Reservoirs are often used to generate electricity in hydropower plants . Drinking water is also often obtained from reservoirs and sufficiently clean natural lakes .

Records and data

Faakersee in Austria
Frozen Ammersee in Bavaria

Worldwide there are 1.4 million lakes with surfaces larger than ten hectares. The country with the most lakes is Canada with over 900,000 lakes. Finland has 187,888 lakes. The entire water of all lakes would cover the entire land surface 1.30 meters high. On average, the water in a lake changes completely every five years. The ten largest lakes in the world contain 85 percent of the water of all lakes. The Lake Baikal alone contains one fifth of all the fresh water on earth.

Largest area

lake surface depth location Water type
Caspian Sea 393,898 km² 995 m Russia , Kazakhstan , Azerbaijan ,
Iran , Turkmenistan
Salt water
Lake Superior 82,414 km² 405 m USA , Canada Freshwater
Lake Victoria 68,870 km² 81/85 m Tanzania , Kenya , Uganda Freshwater
Lake Huron 59,596 km² 229 m USA, Canada Freshwater
Lake Michigan 58,016 km² 281 m United States Freshwater
Lake Tanganyika 32,893 km² 1,470 m Democratic Republic of the Congo , Tanzania, Zambia , Burundi Freshwater
Big Bear Lake 31,792 km² 446 m Canada Freshwater
Baikal lake 31,492 km² 1,642 m Russia Freshwater
Lake Malawi 29,600 km² 706 m Malawi , Tanzania, Mozambique Freshwater
Great slave lake 28,438 km² 614 m Canada Freshwater
Lake Erie 25,745 km² 64 m USA, Canada Freshwater
Winnipeg Lake 24,341 km² 18 m Canada Freshwater
Lake Ontario 19,259 km² 244 m USA, Canada Freshwater
Lake Balkhash 18,428 km² 26 m Kazakhstan Brackish water
Lake Ladoga 17,703 km² 255 m Russia Freshwater
A lake in the Spreewald
A lake in central Finland
The Isernhagen lake in Calvörde am Drömling

Deepest lakes

lake depth surface location Water type
Baikal lake 1,642 m 31,492 km² Russia Freshwater
Lake Tanganyika 1,470 m 32,893 km² Democratic Republic of the Congo , Tanzania , Zambia , Burundi Freshwater
Caspian Sea 995 m 393,898 km² Russia , Kazakhstan,
Azerbaijan , Iran , Turkmenistan
Salt water
Lake Malawi 706 m 29,600 km² Malawi , Tanzania , Mozambique Freshwater
Lake Vostok 670 m 15,690 km² Antarctic Freshwater
Issyk Kul 668 m 6,236 km² Kyrgyzstan Freshwater
Great slave lake 614 m 28,438 km² Canada Freshwater
Crater Lake 594 m 53 km² United States Freshwater
Lago General Carrera 590 m 2,200 km² Chile , Argentina Freshwater
Hornindalsvatnet 514 m 50 km² Norway Freshwater
Lake Toba 505 m 1,103 km² Indonesia , Sumatra Freshwater
Lake Tahoe 501 m 497 km² United States Freshwater
Lake Argentino 500 m 1,466 km² Argentina Freshwater
Lake Hauroko 463 m 63 km² New Zealand Freshwater
Nahuel Huapi 460 m 531 km² Argentina Freshwater
Lake Van 457 m 3,740 km² Turkey soda water
Big Bear Lake 446 m 31,153 km² Canada Freshwater
Lake Como 425 m 146 km² Italy Freshwater
Lake Superior 405 m 82,414 km² USA , Canada Freshwater
Garda lake 346 m 370 km² Italy Freshwater

Highest lake

The Lhagba Pool in Tibet was 6,368 m high, but its classification as a lake (instead of a meltwater pool ) was controversial. The lake no longer exists today. According to this, the crater lake of the 5920 m high Licancabur volcano on the border between Bolivia and Chile is the highest lake on earth.

The Lake Titicaca is located 3,810 m above sea level and is the highest commercially navigable waters of the earth.

Deepest lake

Lake with the clearest water

The Blue Lake in the Tasman region of New Zealand has the highest visibility of all natural freshwater bodies of 70–80 meters. Distilled water for laboratory use has a visibility of about 80 m.

Underground lakes

There are lakes hidden under glacial ice in Greenland and Antarctica .

Caves and underground mines can have lakes. A higher-lying water-filled chamber in the mountain is called a water sac in the mountain world .

The (artificial) Seegrotte in Lower Austria was created by opening a water bag through a man-made blast . The (natural) Lac Souterrain de Saint-Léonard in Switzerland is also used by boats with tourists.

ecology

The rise in the CO 2 concentration in the earth's atmosphere in the Anthropocene leads not only to acidification of the world's oceans but also to acidification of lakes.

Lakes outside the earth

Images from the Cassini space probe showed that there are lakes of liquid methane and ethane on Saturn's moon Titan , which are fed by rivers. The average temperature of titanium is –179 ° C, which means that the methane remains liquid. The largest lake of Titan is the Kraken Mare with around 400,000 square kilometers .

Under the ice cap at the south pole of Mars , a lake containing salt water with a horizontal extension of 20 km was discovered using the radar of the Mars Express 2018 probe . Underground lakes are also conceivable on the icy moons of Jupiter and Saturn (planet) .

Lake and sea in Low German

In Low German (and also in Dutch ) the word meanings of “sea” and “lake” are interchanged in relation to High German: The seas bordering northern Germany are called the North Sea and the Baltic Sea (both the sea); in the interior are z. B. the Steinhuder Sea , the Zwischenahner Sea , the Great Sea and others; in the Netherlands the Zuiderzee was renamed the IJsselmeer after it was dyed .

Rough or high seas (the ...) means high swell, so high waves at the sea.

See also

Web links

Commons : See  - collection of pictures, videos and audio files
Wiktionary: See  - explanations of meanings, origins of words, synonyms, translations
Wikiquote: See  Quotes

supporting documents

  1. Rüdiger Mauersberger: Classification of the lakes for natural space exploration of the northeast German lowlands. Templin, 2006.
  2. From the water. In: Süddeutsche Zeitung , December 16, 2016, p. 14.
  3. a b Nelson’s Blue Lake - The clearest freshwater ever reported. In: NIWA. Retrieved December 20, 2011 .
  4. Nelson's Blue Lake clearest. In: New Zealand Herald. December 20, 2011, accessed December 20, 2011 .
  5. Discovered underground lake on Mars orf.at, July 25, 2018, accessed on July 25, 2018.
  6. CO2 in air and water - acidification also affects freshwater animals . In: Deutschlandfunk . ( deutschlandfunk.de [accessed on February 4, 2018]).
  7. Discovered underground lake on Mars orf.at, July 25, 2018, accessed on July 25, 2018.