Lakes



A lake is a body of relatively still water of considerable size, localized in a basin, that is surrounded by land apart from a river, stream, or other form of moving water that serves to feed or drain the lake. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds Lakes can be contrasted with rivers or streams, which are usually flowing. However most lakes are fed and drained by rivers and streams.

Natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers. In some parts of the world there are many lakes because of chaotic drainage patterns left over from the last Ice Age. All lakes are temporary over geologic time scales, as they will slowly fill in with sediments or spill out of the basin containing them.

Many lakes are artificial and are constructed for industrial or agricultural use, for hydro-electric power generation or domestic water supply, or for aesthetic or recreational purposes.




Pseudoscience: Extraterrestrials Lakes

In creation myths and pseudoscience, lakes are sometimes referenced as the place the gods descended to - or emerged from - to create humanity. There is always the message that these gods will return one day.

Dogon Mythology - The Nommo


Amphibious Gods


Many believe there are subterranean alien bases under lakes and oceans. UFO's are seen rising form the water by locals in places such as Lake Titicaca, where legends of ancient astronauts who visited the planet thousands of years ago, are common. USOs - Unidentified Submerged Objects




In the News ...





Lakes are changing worldwide - lake temperatures are rising and seasonal ice cover is becoming shorter and thinner   PhysOrg - October 18, 2021
This affects lake ecosystems, drinking water supply and fishing.



Study shows water hundreds of feet below the surface of Lake Michigan is warming   PhysOrg - March 22, 2021
Water hundreds of feet below the surface of Lake Michigan is warming, especially in winter, according to a report published last week by the National Oceanic and Atmospheric Administration. The warming could change the seasonal patterns of the lake - and alter a way of life for ecosystems and industry alike. It's been known that Lake Michigan surface temperatures are increasing and ice cover is lessening as human activity spurs climate change.




Great Lakes continue to rise; Lakes Michigan, Huron likely to top records September   PhysOrg - June 10, 2020
Experts predict record-breaking levels this summer as the Great Lakes continue to rise as two of the lakes and Lake St. Clair set new monthly records in May. Lakes Michigan, Huron, St. Clair and Erie broke monthly water level records in May that were previously set in 1986, U.S. Army Corps of Engineers officials said. Lakes Michigan-Huron and St. Clair smashed the all-time high marks by 4 inches, while Lake Erie bested its record by one inch. The same lakes set monthly records in April.




Massive 'lake' discovered under volcano could unlock why and how volcanoes erupt   Science Daily - November 8, 2016
A huge magmatic lake has been discovered, 15 kilometers below a dormant volcano in Bolivia, South America. The body of water, which is dissolved into partially molten rock at a temperature of almost 1,000 degrees Celsius, is the equivalent to what is found in some of the world's giant freshwater lakes, such as Lake Superior. The find has now led scientists to consider if similar bodies of water may be 'hiding' under other volcanoes and could help explain why and how volcanoes erupt.




Ancient lake challenges understanding of evolution   PhysOrg - May 20, 2015
Scientists have studied samples of lake sediments deposited 1.5 billion years ago in the Bay of Stoer region in north-west Scotland, and discovered high levels of the metal molybdenum, a key element in the evolution of multicellular life. The discovery challenges the commonly held view that an important stage of evolution, leading eventually to human life, occurred in the deep ocean, as opposed to a continental environment.




Types of Lakes

Periglacial: Part of the lake's margin is formed by an ice sheet, ice cap, or glacier, the ice having obstructed the natural drainage of the land.

Subglacial: A lake which is permanently covered by ice. They can occur under glaciers, ice caps, or ice sheets. There are many such lakes, but Lake Vostok in Antarctica is by far the largest. They are kept liquid because the overlying ice acts as a thermal insulator retaining energy introduced to its underside by friction, by water percolating through crevasses, by the pressure from the mass of the ice sheet above, or by geothermal heating below.

Glacial lake: a lake with origins in a melted glacier.

Artificial: A lake created by flooding land behind a dam, called an impoundment or reservoir; by deliberate human excavation; or by the flooding of an excavation incident to a mineral-extraction operation such as an open pit mine or quarry. Some of the world's largest lakes are reservoirs.

Endorheic, also called terminal or closed: A lake which has no significant outflow, either through rivers or underground diffusion. Any water within an endorheic basin leaves the system only through evaporation or seepage. These lakes, such as Lake Eyre in central Australia or the Aral Sea in central Asia, are most common in desert locations.

Meromictic: A lake which has layers of water which do not intermix. The deepest layer of water in such a lake does not contain any dissolved oxygen. The layers of sediment at the bottom of a meromictic lake remain relatively undisturbed because there are no living aerobic organisms.

Fjord lake: A lake in a glacially eroded valley that has been eroded below sea level.

Oxbow: A lake which is formed when a wide meander from a stream or a river is cut off to form a lake. They are called "oxbow" lakes due to the distinctive curved shape that results from this process.

Rift lake: A lake which forms as a result of subsidence along a geological fault in the Earth's tectonic plates. Examples include the Rift Valley lakes of eastern Africa and Lake Baikal in Siberia.

Underground: A lake which is formed under the surface of the Earth's crust. Such a lake may be associated with caves, aquifers, or spring

Crater: A lake which forms in a volcanic caldera or crater after the volcano has been inactive for some time. Water in this type of lake may be fresh or highly acidic and may contain various dissolved minerals. Some also have geothermal activity, especially if the volcano is merely dormant rather than extinct.

Lava: A pool of molten lava contained in a volcanic crater or other depression. Lava lakes that have partly or completely solidified are also referred to as lava lakes.

Former: A lake which is no longer in existence. Such lakes include prehistoric lakes and lakes which have permanently dried up through evaporation or human intervention. Owens Lake in California, USA, is an example of a former lake. Former lakes are a common feature of the Basin and Range area of southwestern North America.

Seasonal lake: A lake that exists as a body of water during only part of the year.

Shrunken: Closely related to former lakes, a shrunken lake is one which has drastically decreased in size over geological time. Lake Agassiz, which once covered much of central North America, is a good example of a shrunken lake. Two notable remnants of this lake are Lake Winnipeg and Lake Winnipegosis.

Eolic: A lake which forms in a depression created by the activity of the winds.




How Lakes Disappear

A lake may be infilled with deposited sediment and gradually become a wetland such as a swamp or marsh. Large water plants, typically reeds, accelerate this closing process significantly because they partially decompose to form peat soils that fill the shallows. Conversely, peat soils in a marsh can naturally burn and reverse this process to recreate a shallow lake.

Turbid lakes and lakes with many plant-eating fish tend to disappear more slowly. A "disappearing" lake (barely noticeable on a human timescale) typically has extensive plant mats at the water's edge. These become a new habitat for other plants, like peat moss when conditions are right, and animals, many of which are very rare. Gradually the lake closes, and young peat may form, forming a fen. In lowland river valleys, where a river can meander, the presence of peat is explained by the infilling of historical oxbow lakes. In the very last stages of succession, trees can grow in, eventually turning the wetland into a forest.

Some lakes can disappear seasonally. These are called intermittent lakes and are typically found in karstic terrain. A prime example of an intermittent lake is Lake Cerknica in Slovenia. Sometimes a lake will disappear quickly. On 3 June 2005, in Nizhny Novgorod Oblast, Russia, a lake called Lake Beloye vanished in a matter of minutes. 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.

The presence of ground permafrost is important to the persistence of some lakes. According to research published in the journal Science ("Disappearing Arctic Lakes," June 2005), thawing permafrost may explain the shrinking or disappearance of hundreds of large Arctic lakes across western Siberia. The idea here is that rising air and soil temperatures thaw permafrost, allowing the lakes to drain away into the ground.

Neusiedler See, located in Austria and Hungary, has dried up many times over the millennia. As of 2005, it is again rapidly losing water, giving rise to the fear that it will be completely dry by 2010.

Some lakes disappear because of human development factors. The shrinking Aral Sea is described as being "murdered" by the diversion for irrigation of the rivers feeding it.




Great Lakes


The Great Lakes (sometimes, Laurentian Great Lakes) are a collection of freshwater lakes located in northeastern North America, on the CanadaŠUnited States border, which connect to the Atlantic Ocean through the Saint Lawrence Seaway and the Great Lakes Waterway. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth, containing 21% of the world's surface fresh water. ,p> The total surface is 94,250 square miles (244,106 km2), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km3). The lakes are sometimes referred to as the North Coast or "Third Coast" by some citizens of the United States. They have also been referred to as North America's fourth coast, as traversing the shoreline of each of the lakes covers about 17,000 km (11,000 mi) roughly the distance of almost half the Earth's equator.

The Great Lakes began to form at the end of the last glacial period around 10,000 years ago, as retreating ice sheets carved basins into the land and they became filled with meltwater. The lakes have been a major source of trade through their region, and are home to a large number of aquatic species. Many invasive species have been introduced due to trade in the area, and some threaten the region's biodiversity. Read more ...




Antarctica


Lake Vostok is the largest of Antarctica's almost 400 known subglacial lakes. Lake Vostok is located at the southern Pole of Cold, beneath Russia's Vostok Station under the surface of the central East Antarctic Ice Sheet, which is at 3,488 m (11,444 ft) above mean sea level. The surface of this fresh water lake is approximately 4,000 m (13,100 ft) under the surface of the ice, which places it at approximately 500 m (1,600 ft) below sea level. Measuring 250 km (160 mi) long by 50 km (30 mi) wide at its widest point, and covering an area of 12,500 km2 (4,830 sq mi) and an average depth of 432 m (1,417 ft), it has an estimated volume of 5,400 km3 (1,300 cu mi). The lake is divided into two deep basins by a ridge. The liquid water over the ridge is about 200 m (700 ft), compared to roughly 400 m (1,300 ft) deep in the northern basin and 800 m (2,600 ft) deep in the southern. Read more ...




Extraterrestrial Lakes


Spring on Saturn's Moon Titan Reveals Amazing Views of Otherworldly Lakes (Photos)   Live Science - October 25, 2013

NASA's Cassini space probe is getting an exceptional look at the vast liquid lakes of Titan's north pole, where dense winter clouds are finally retreating thanks to a change in seasons on Saturn's largest moon. A clearer view of Titan's wet northern region could provide clues about the moon's hydrologic cycle and the evolution of its seas. New images released by NASA this week even revealed the Titan equivalent of salt flats surrounding its northern lakes, some of which are as big as the Caspian Sea and Lake Superior combined. Titan more closely resembles Earth than any other planet or moon in our solar system, with a dense atmosphere and stable liquids on its surface. But Titan's clouds, lakes and rain are made up of hydrocarbons, such as ethane and methane, rather than water.





At present the surface of the planet Mars is too cold and has too little atmospheric pressure to permit the pooling of liquid water on the surface. Geologic evidence appears to confirm, however, that ancient lakes once formed on the surface. It is also possible that volcanic activity on Mars will occasionally melt subsurface ice, creating large lakes. Under current conditions this water would quickly freeze and evaporate unless insulated in some manner, such as by a coating of volcanic ash.





Only one world other than Earth is known to harbor lakes, Saturn's largest moon, Titan. Photographs and spectroscopic analysis by the Cassini-Huygens spacecraft show liquid ethane on the surface, which is thought to be mixed with liquid methane.





Jupiter's small moon Io is volcanically active due to tidal stresses, and as a result sulfur deposits have accumulated on the surface. Some photographs taken during the Galileo mission appear to show lakes of liquid sulfur on the surface.





There are dark basaltic plains on the Moon, similar to lunar maria but smaller, that are called lacus (singular lacus, Latin for "lake") because they were thought by early astronomers to be lakes of water.




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