Lake

A lake is a pond with or without inflow and outflow through flowing water that is completely surrounded by land area. He provides a largely closed ecosystem is (see lake ecosystem ).

Definition

A lake is an inland sea, which is a (larger) accumulation of water in a bottom well of a land area and in contrast to an inland sea (for example, the Mediterranean which ) on the 0 -meter contour line has no direct connection to the ocean. He does not have due to ocean currents and / or runoff. Inflow and outflow quantity are usually small compared to the total amount of water of a lake. Unlike a river, a lake on no gradient.

The term lake is needed to delineate lakes inland from coastal lakes ( lakes beach, coastal brackish lakes or created by diking of coastal lakes ), but also commonly used to designate lakes.

A lake in the sense of limnological definition is much deeper than a pond, pool or pond in the rule, so that a stable for days to months temperature stratification can form. The frequency of their mixing is used for a classification of lakes as it has far- reaching ecological consequences (see lake ecosystem ). In this respect, the flat steppe lakes such as Lake Neusiedl or the Balaton are not " real" lakes.

However, the exact demarcation between lakes and ponds / lakes etc. is fuzzy and subjective. Therefore, some limnologists refer to any water-filled sink as a lake. Would be irrelevant to its classification, whether a lake is constantly, periodically or episodically filled with water and if it forms a permanent stratification.

A lake contains mostly freshwater, but there are also large salt lakes, such as the Caspian Sea, the Aral Sea and the Dead Sea. Also contain soda lakes, there are, for example, the Rift Valley in East African grave breach such as the Lake Nakuru or some of the ponds around Lake Neusiedl.

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

In astronomy, one speaks also of lakes, if they contain a liquid other than water, such as the methane lakes on Titan.

Formation of lakes

Geologic and geomorphologic hall, the following marine species:

• It naturally formed lakes.
• Artificial artificial lakes. They called you - depending on the nature of their investment - as a lake or reservoir. Also, by diking of bays may arise, for example, the IJsselmeer artificial lakes.

Naturally formed lakes can be further subdivided according to the nature of their origin:

• Glacial lakes formed by the erosive action of glaciers or aufschüttende or by glacial melt water. This is the world's most common type lakes (eg the Great Lakes in North America or the numerous lakes in North and South).
• Edge of the glacier lakes and lakes are Eisstauseen short lifetime of active glaciers.
• Tectonic lakes caused by stretching of the crust and the thus resulting cracks and grave breaches, such as the Lake Baikal. In the East African grave breach is a long chain of lakes, which also includes the 1470 m deep Lake Tanganyika is one formed. The tectonic lakes include most endorheic Endseen in drylands, as they are usually within subsidence areas.
• Abdämmungsseen caused by landslides in the mountains or along coastlines by pinch of sea bays. The latter are also referred to as beach lakes.
• Karst or Erdfallseen caused by carbonate or salt solution ( Subrosion ) underground and sagging of the earth's surface, such as the Arendsee and the sweetness lake in Saxony- Anhalt.
• Lakes, which are created by volcanic activities ( volcanic lake ). Examples in Germany are the maars in the Eifel region, including Laachersee.
• Lakes within meteorite craters such as the Elgygytgyn.
• Oxbow lakes caused by natural shifting of river courses. The old river bed then remains as an elongated lake back (eg camera shear lake at mountain Havel ).
• Thermokarst lakes occur in areas with permafrost, such as in Alaska or northern Siberia.
• Lakes with a complex history. So the lake Vättern in Sweden is for example inside a grave breach, the basin was carved out but mainly by glaciers.

Use

Natural and man-made lakes offer in addition to their importance for nature also some potential uses for humans.

Most lakes are managed either by professional or fishing fishermen. Furthermore lakes can be used as a lake for leisure and recreation, swimming and bathing. Larger lakes offer opportunities for water skiing, windsurfing and sailing. At many large lakes and inland navigation exists. Reservoirs often serve the electricity in hydroelectric plants. For reservoirs and sufficiently clean drinking water natural lakes is often won.

Records

Largest Area

Deepest lakes

Highest Lake

The Lhagba Pool in Tibet is 6,368 m high, its classification as a lake ( instead of a melt-water pools) is controversial. After that, the crater of the 5920 m high volcano Licancabur on the border between Bolivia and Chile is considered to be the highest lake in the world.

Lake Titicaca is located 3810 m above sea level and is the highest commercially navigable waters of the earth.

Deeply situated lake

• The Dead Sea is 420 meters below sea level.
• The Lake Vostok is 3700-4000 meters below the surface of the ice of Antarctica.

Lake with the clearest water

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

Lakes outside of Earth

Recordings of the Cassini spacecraft showed that exist on Saturn's moon Titan seas of liquid methane and ethane, which are fed by rivers. The average temperature of Titan is -179 ° C, thus the methane remains liquid. The largest lake of titanium is approximately 400,000 square kilometers, the Kraken Mare.

Others

In the Low German (as well as in Dutch ) are the word meanings of " sea " and "lake" reversed: The adjoining northern Germany seas hot North Sea and Baltic Sea ( the sea ); inland, however, are for example the Steinhude, the Zwischenahner Sea, the Great Sea, and others; in the Netherlands the Zuiderzee was renamed after its reclamation in the IJsselmeer.