Lake

Lakes are typically larger and deeper than ponds, which are also water-filled basins on land, although there are no official definitions or scientific criteria distinguishing the two.

Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ice age.

All lakes are temporary over long periods of time, as they will slowly fill in with sediments or spill out of the basin containing them.

Artificially controlled lakes are known as reservoirs, and are usually constructed for industrial or agricultural use, for hydroelectric power generation, for supplying domestic drinking water, for ecological or recreational purposes, or for other human activities.

There is considerable uncertainty about defining the difference between lakes and ponds, and neither term has an internationally accepted definition across scientific disciplines or political boundaries.

[12] Canada, with a deranged drainage system, has an estimated 31,752 lakes larger than 3 square kilometres (1.2 sq mi) in surface area.

For example, one widely cited study estimated that Earth has 304 million lakes and ponds, and that 91% of these are 1 hectare (2.5 acres) or less in area.

[18][25][26] In 1957, G. Evelyn Hutchinson published a monograph titled A Treatise on Limnology,[27] which is regarded as a landmark discussion and classification of all major lake types, their origin, morphometric characteristics, and distribution.

They form where there is no natural outlet, a high evaporation rate and the drainage surface of the water table has a higher-than-normal salt content.

Most lakes in northern Europe and North America have been either influenced or created by the latest, but not last, glaciation, to have covered the region.

In areas underlain by soluble bedrock, its solution by precipitation and percolating water commonly produce cavities.

Classic examples of solution lakes are abundant in the karst regions at the Dalmatian coast of Croatia and within large parts of Florida.

In 1911, an earthquake triggered a landslide that blocked a deep valley in the Pamir Mountains region of Tajikistan, forming the Sarez Lake.

They form where a buildup of partly decomposed plant material in a wet environment leaves the vegetated surface below the water table for a sustained period of time.

The Upper Silesian region of southern Poland contains an anthropogenic lake district consisting of more than 4,000 water bodies created by human activity.

[45] As in the cases of El'gygytgyn and Pingualuit, meteorite lakes can contain unique and scientifically valuable sedimentary deposits associated with long records of paleoclimatic changes.

For example, the thermal stratification, as well as the degree and frequency of mixing, has a strong control over the distribution of oxygen within the lake.

Finally, overlying the metalimnion is a surface layer of warmer water with a lower density, called the epilimnion.

This typical stratification sequence can vary widely, depending on the specific lake or the time of year, or a combination of both.

The deepest layer of water in a meromictic lake does not contain any dissolved oxygen so there are no living aerobic organisms.

Consequently, the layers of sediment at the bottom of a meromictic lake remain relatively undisturbed, which allows for the development of lacustrine deposits.

The paleoshorelines and sedimentary deposits of paleolakes provide evidence for prehistoric hydrological changes during the times that they existed.

Exceptional events, such as earthquakes or landslides, can cause mixing which rapidly brings the deep layers up to the surface and release a vast cloud of gas which lay trapped in solution in the colder water at the bottom of the lake.

Under these circumstances carbon dioxide is hazardous because it is heavier than air and displaces it, so it may flow down a river valley to human settlements and cause mass asphyxiation.

A lake moderates the surrounding region's temperature and climate because water has a very high specific heat capacity (4,186 J·kg−1·K−1).

Large water plants, typically reeds, accelerate this closing process significantly because they partially decompose to form peat soils that fill the shallows.

A "disappearing" lake (barely noticeable on a human timescale) typically has extensive plant mats at the water's edge.

News sources reported that government officials theorized that this strange phenomenon may have been caused by a shift in the soil underneath the lake that allowed its water to drain through channels leading to the Oka River.

Thawing permafrost may explain the shrinking or disappearance of hundreds of large Arctic lakes across western Siberia.

[citation needed] Between 1990 and 2020, more than half of the world's large lakes decreased in size, in part due to climate change.