Other Definitions
lake (dict)
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Lake A lake is a large body of water, usually fresh water, surrounded by land. Large lakes are sometimes referred to as "inland seas" and small seas are sometimes referred to as lakes. For examples (of saline lakes): the Great Salt Lake, and the Dead Sea. The largest "lake" in the world is the Caspian Sea, and the deepest is Lake Baikal in Siberia. The largest highest lake is lake Titicaca. The term lake is also used to describe a feature such as Lake Eyre, which is dry most of the time but becomes filled under seasonal conditions of heavy rainfall. Many lakes are artificial and are constructed for hydro-electric power supply, recreation (wind surfing), water supply, etc. There are dark basaltic plains on the Moon, similar to lunar maria but smaller, that are called lacus (singular lacus, Latin for "lake"). They were once thought by early astronomers to be literal lakes. Origin of natural lakes Most lakes are young, and are the result of the glaciers from the last ice age, for instance those in Scandinavia, Siberia and Canada. Finland is known as The Land of the Thousand Lakes and Minnesota is known as The Land of Ten Thousand Lakes. The Great Lakes of North America also have ice age origins. Over 60% of the world's lakes are in Canada; this is because of the deranged drainage system that dominates the country. Lake Vostok is an under-ice lake in Antarctica, possibly the largest in the world. The pressure from ice and the internal chemical composition means that if the lake were drilled into, it may result in a fissure and spraying in the same manner as a shaken can of soda. Some lakes, like lake Baikal and lake Tanganyika are volcanic in origin, and lie at geological fault lines. Artificial lakes Lokka is Northern Europe's largest artificial lake, 417 km2 in size. Abiotic and biotic limnology A lake has three zones: littoral zone, which is a sloped area that is close to land; open-water zone, where sunlight is abundant; and deep-water zone, where little sunlight can reach. The depth which light can reach in lakes depends on the density and motion of particles. These particles can be sedimentary or biological in origin and are responsible for the color of the water. Decaying plant matter for instance is responsible for a yellow or brown color, while algae result in greenish water. In very shallow water bodies, iron oxides make water reddish brown. Biological particles are algae and detritus. Sediment is in suspension if its mass is less than its buoyancy. The turbidity is a decisive factor in the transparency of the water. Bottom-dwelling detritivorous fish are responsible for turbid waters, as are piscivorous fish (see Aquatic trophic cascade). The light depth or transparency is measured by using a Secchi disk. This is a 20 cm disk with alternating white and black quadrants. The depth at which the disk is no longer visible, is the Secchi depth, and is a measure for transparency. It is commonly used to test eutrophication. A lake moderates the surrounding region's temperature and climate because water has a very high specific heat capacity (4186). How lakes disappear A lake may be deposited with minerals and sediment, and gradually, the lake becomes a wetland, such as a swamp or marsh. More trees would grow in, eventually turning the wetland into a forest See also External links
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