Mono Lake Landsat image of Mono Lake Location Mono County, California Coordinates 38°01′00″N 119°00′34″W / 38.0165908°N 119.0093116°W / 38.0165908; -119.0093116Coordinates: 38°01′00″N 119°00′34″W / 38.0165908°N 119.0093116°W / 38.0165908; -119.0093116 Lake type Endorheic, Monomictic Primary inflows Rush Creek, Lee Vining Creek, Mill Creek Primary outflows Evaporation Catchment area 2,030 km2 (780 sq mi) Basin countries United States Max. length 15 km (9.3 mi) Max. width 21 km (13 mi) Surface area 45,133 acres (182.65 km2)[1] Average depth 17 m (56 ft) Max. depth 48 m (157 ft) Water volume 2,970,000 acre·ft (3.66 km3) Surface elevation 6,378 ft (1,944 m) above sea level Islands Two major: Negit Island and Paoha Island; numerous minor outcroppings (including tufa rock formations). The lake's water level is notably variable. References U.S. Geological Survey Geographic Names Information System: Mono Lake Relief map of Mono Lake and surrounding area, including nearby Lake Tahoe and Yosemite National Park (area within yellow boundaries); California-Nevada state border shown

Mono Lake (/ˈmoʊnoʊ/ MOH-noh) is a large, shallow saline lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in a basin that has no outlet to the ocean. The lack of an outlet causes high levels of salts to accumulate in the lake. These salts also make the lake water alkaline.

This desert lake has an unusually productive ecosystem based on brine shrimp that thrive in its waters, and provides critical nesting habitat for two million annual migratory birds that feed on the shrimp.^[2][3] Mono Lake is also notable for containing GFAJ-1, a rod-shaped extremophilic species of bacteria that may be capable of metabolizing the usually poisonous element arsenic.^[4]

The human history of Mono Lake is associated with its productive ecosystem. The native Kutzadika'a people derived nutrition from the larvae of the alkaline flies that live in the lake. When the city of Los Angeles diverted water from flowing into the lake, it lowered the lake level, which imperiled the migratory birds. The Mono Lake Committee formed in response, winning a legal battle that forced Los Angeles to partially restore the lake level.

Geology[link]

USGS map of the Mono Lake area, showing geological features

Mono Lake formed because it lies in the Mono Basin, an endorheic basin that has no outlet to the ocean. Dissolved salts in the runoff thus remain in the lake and raise the water's pH levels and salt concentration. The tributaries of Mono Lake include Lee Vining Creek, Rush Creek and Mill Creek which flows through Lundy Canyon.^[5]

The basin was created by geological forces over the last five million years: basin and range crustal stretching and associated volcanism and faulting at the base of the Sierra Nevada.^[6] Five million years ago, the Sierra Nevada was an eroded set of rolling hills and Mono Basin and Owens Valley did not yet exist.

From 4.5 to 2.6 million years ago, large volumes of basalt were erupted around what is now Cowtrack Mountain (east and south of Mono Basin); eventually covering 300 square miles (780 km²) and reaching a maximum thickness of 600 feet (180 m).^[6] Later volcanism in the area occurred 3.8 million to 250,000 years ago.^[7] This activity was northwest of Mono Basin and included the formation of Aurora Crater, Beauty Peak, Cedar Hill (later an island in the highest stands of Mono Lake), and Mount Hicks.

Mono Lake is believed to have formed at least 760,000 years ago, dating back to the Long Valley eruption. Sediments located below the ash layer hint that Mono Lake could be a remnant of a larger and older lake that once covered a large part of Nevada and Utah, which would put it among the oldest lakes in North America. At its height during the most recent ice age, the lake may have been 900 feet (270 m) deep.^[8] Prominent old shore lines, called strandlines by geologists, can be seen above Lee Vining and along volcanic hills northeast of the current lake.

Currently, Mono Lake is in a geologically active area at the north end of the Mono–Inyo Craters volcanic chain and is close to Long Valley Caldera. Volcanic activity continues in the Mono Lake vicinity: the most recent eruption occurred 350 years ago, resulting in the formation of Paoha Island. Panum Crater (on the south shore of the lake) is an excellent example of a combined rhyolite dome and cinder cone.

Lakeside of Mono Lake, 1999

Limnology[link]

The limnology of the lake shows it contains approximately 280 million tons of dissolved salts, with the salinity varying depending upon the amount of water in the lake at any given time. Before 1941, average salinity was approximately 50 grams per liter (g/l) (compared to a value of 31.5 g/l for the world's oceans). In January 1982, when the lake reached its lowest level of 6,372 feet (1,942 m), the salinity had nearly doubled to 99 g/l. In 2002, it was measured at 78 g/l and is expected to stabilize at an average 69 g/l as the lake replenishes over the next 20 years.^[9]

An important, and unintentional, consequence of ending the water diversions was the onset of a period of "meromixis" in Mono Lake.^[10] In the time prior to this, Mono Lake was typically "monomictic"; which means that at least once each year the deeper waters and the shallower waters of the lake mixed thoroughly, thus bringing oxygen and other nutrients to the deep waters. In meromictic lakes, the deeper waters do not undergo this mixing; the deeper layers are more saline than the water near the surface, and are typically nearly devoid of oxygen. As a result, becoming meromictic greatly changes a lake's ecology.

Mono Lake has experienced meromictic periods in the past; this most recent episode of meromixis, brought on by the end of the water diversions, commenced in 1994 and had ended by 2004.^[11]

Mono Lake alkali flies

Ecology[link]

Fauna[link]

The hypersalinity and high alkalinity (pH=10 or equivalent to 4 milligrams of NaOH per liter of water) of the lake means that no fish are native to the lake.^[12] An attempt by the California Department of Fish and Game to stock the lake failed.

Aquatic life[link]

The lake is famous for the Mono Lake brine shrimp, Artemia monica, a tiny species of brine shrimp, no bigger than a thumbnail, that are endemic. During the warmer summer months, an estimated 4-6 trillion brine shrimp inhabit the lake. Brine shrimp have no food value for humans, but are a staple for birds of the region. The brine shrimp feed on microscopic planktonic algae which reproduce rapidly during winter and early spring after winter runoff brings nutrients to the surface layer of water.

The whole food chain of the lake is based on the high population of single-celled algae present in the warm shallow waters. By March the lake is "as green as pea soup" with photosynthesizing algae.^[13] Alkali flies, Ephydra hians live along the shores of the lake and walk underwater encased in small air bubbles for grazing and to lay eggs. These flies are an important source of food for migratory and nesting birds.

California gull (Larus californicus)

Birds[link]

Mono Lake is a vital resting and eating stop for migratory shorebirds and has been recognized as a site of international importance by the Western Hemisphere Shorebird Reserve Network.^[14] Nearly 2,000,000 waterbirds, including 35 species of shorebirds, use Mono Lake to rest and eat for at least part of the year. Some shorebirds that depend on the resources of Mono Lake include American avocets, killdeer and sandpipers. Over 1.5 million eared grebes and phalaropes use Mono Lake during their long migrations.

Late every summer tens of thousands of Wilson's phalaropes and red-necked phalaropes arrive from their nesting grounds, and feed until they continue their migration to South America or the tropical oceans respectively.^[2]

In addition to migratory birds, a few species spend several months to nest at Mono Lake. Mono Lake is the second largest nesting population of California gulls, Larus californicus, second only to the Great Salt Lake in Utah. Since abandoning the landbridged Negit Island in the late 1970s, California gulls have moved to some nearby islets and have established new, if less protected, nesting sites. Cornell University and Point Reyes Bird Observatory have continued the study of nesting populations on Mono Lake that was begun over 20 years ago. Snowy Plovers also arrive at Mono Lake each spring to nest along the remote eastern shores.

Arsenic-using bacteria[link]

On December 2, 2010, NASA announced the discovery of an organism in Mono Lake, named GFAJ-1, that utilizes arsenic in its cellular structure.^[15] If confirmed, this would constitute the first discovery of a life form capable of replacing one of the six essential elements (carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus) in its biomolecules.^[16][17][18]

History[link]

Native Americans[link]

The early indigenous people of Mono Lake were called the Kutzadika'a, who were the Native American band of Northern Paiutes.^[19] They spoke the Northern Paiute language.^[20] The Kutzadika'a foraged alkali fly larvae, called kutsavi in their language.^[21] Mono Lake was also referred to as Teniega Bah. The origin of the name "Kutzadika'a" is uncertain but could be a Yokut Native American term for "fly eater".

The term "Mono" came from "Monachi", a Yokut term for the tribes that lived on both the east and west side of the Sierra Nevada.^[22]

During early contact the first known Mono Lake Paiute chief was Captain John. He was also referred to by the Paiute names of Shibana or Poko Tucket. Captain John was the son of a Northern Paiute named 'older Captain John.'

The Mono tribe has two bands: Eastern and Western. The Eastern Mono joined the Western Mono bands' villages annually at Hetch Hetchy Valley, Yosemite Valley, and along the Merced River to gather acorns, different plant species, and to trade. The Western Mono traditionally lived in the south-central Sierra Nevada foothills, including Historical Yosemite Valley.^[23]

Present day Mono Reservations are currently located in Big Pine, Bishop, and several in Fresno County, California.

Exposed tufa towers in Mono Lake; South Tufa, 1981

Conservation efforts[link]

In order to provide water needs for the growing City of Los Angeles, water was diverted from the Owens River into the Los Angeles Aqueduct in 1913. In 1941 the Los Angeles Department of Water and Power extended the Los Angeles Aqueduct system farther upriver into the Mono Basin. So much water was diverted that evaporation soon exceeded inflow and the surface level of Mono Lake fell rapidly. By 1982 the lake was reduced to 37,688 acres (15,252 ha) having lost 31 percent of its 1941 surface area. As a result alkaline sands and once-submerged tufa towers became exposed and Negit Island became landbridged, exposing the nests of gulls to predators (chiefly coyotes) and forcing the breeding colony to abandon the site.

In 1974, Stanford University graduate student David Gaines studied the Mono Lake ecosystem and was instrumental in alerting the public of the effects of the lower water level.^[24] The National Science Foundation funded the first comprehensive ecological study of Mono Lake, conducted by Gaines and undergraduate students from UC Davis, UC Santa Cruz, and Earlham College. In June 1977 the UC Davis Institute of Ecology published their report, "An Ecological Study of Mono Lake, California," which alerted California to the ecological dangers posed by the redirection of water away from the lake for municipal uses.^[24]

Gaines formed the Mono Lake Committee in 1978. He and Sally Judy, a UC Davis student, led the committee and pursued an informational tour of California. They joined with the Audubon Society to fight a now famous court battle, the National Audubon Society v. Superior Court, to protect Mono Lake through state public trust laws.^[24] While these efforts have resulted in positive change, the surface level is still below historic levels and exposed shorelines are a source of significant alkali dust during periods of high wind.

Mono Lake viewed from the summit of Mount Dana. Note near-landbridge at left, almost connecting Negit Island with the mainland shoreline.

A tufa tower rock formation in Mono Lake, 2006

Owens Lake, the once navigable terminus of the Owens River which had sustained a healthy ecosystem, is now a dry lake bed during dry years due to water diversion beginning in the 1920s. Mono Lake was spared this fate when the California State Water Resources Control Board issued an order to protect Mono Lake and its tributary streams on September 28, 1994. Since that time, the lake level has steadily risen. In 1941 the surface level was at 6,417 feet (1,956 m) above sea level and as of August 2006 it was at 6,385 feet (1,946 m).^[25] As of May 2011, Mono Lake is at 6,382.5 feet (1,945 m) above sea level and is projected to rise 1.6 feet (490 mm) by September in response to the heavy snowpack in the mountains this year. The lake level of 6,392 feet (1,948 m) above sea level is the goal, a goal made more difficult during years of drought in the American West.

In popular culture[link]

• Mark Twain's Roughing It, published in 1872, provides a humorous and informative early description of Mono Lake in its natural condition in the 1860s^[26][27] Twain found the lake to be a "lifeless, treeless, hideous desert... the loneliest place on earth."^[8]
• The general appearance of the lake and surrounding mountains circa 1973 can also be seen in the Clint Eastwood film High Plains Drifter
• The Diver, a photo taken by Storm Thorgerson for Pink Floyd's album Wish You Were Here, features what appears to be a man diving into a lake, creating no ripples. The photo was taken at Mono Lake, and the tufa towers are a prominent part of the landscape. The effect was actually created when the diver performed a handstand underwater until the ripples dissipated.^[28]

• The band Cinderella filmed the video for their power ballad "Don't Know What You Got (Till It's Gone)" at Mono Lake
• Monolake is the stage name of a Berlin minimal techno artist
• The volcano scene from the award-winning 1953 film Fair Wind to Java^[29] was shot at Mono Lake. Today the remnants of the volcano host California gull researchers on their visits to the island.^[30]

See also[link]

Geography portal

• Mono Lake Tufa State Reserve
• Mono Basin National Scenic Area

Notes[link]

References[link]

• Harris, S.L. (2005). Fire Mountains of the West: The Cascade and Mono Lake Volcanoes. Mountain Press. ISBN 978-0-87842-511-2. 
• Miller, C.D.; et al. (1982). "Potential hazards from future volcanic eruptions in the Long Valley-Mono Lake area, east-central California and southwest Nevada : a preliminary assessment". U.S. Geological Survey Circular 877 (Reston, Virginia: U.S. Geological Survey). 
• Morgan, James (2009-02-16). "Alien life 'may exist among us': Mono Lake in the US is home to arsenic-fuelled microbes". BBC NEWS – Science & Environment. http://news.bbc.co.uk/2/hi/science/nature/7893414.stm. Retrieved 2009-02-22. 
• Tierney, Timothy (2000). Geology of the Mono Basin (revised ed.). Lee Vining, California: Kutsavi Press, Mono Lake Committee. ISBN 0-939716-08-9. 

External links[link]

Wikimedia Commons has media related to: Mono Lake

• Mono Lake Area Visitor Information
• Mono Lake Tufa State Nature Reserve
• Mono Lake Committee website
• Mono Lake Visitor Guide
• "World Lake Database entry for Mono Lake". http://wldb.ilec.or.jp/LakeDB2/Lake.asp?LakeID=SNAM-096&RoutePrm=0%3A%3B4%3Aload%3B. Retrieved 2010-12-02. 
• Ecoscenario: Mono Lake - with photos
• Joe Dorward's website with a panoramic view of Mono Lake from Conway Summit
• Landsat image of Mono Lake
• Arsenic-Based Sea Monkeys: humorous spoof specifically based upon unique Mono Lake fauna
• Roadside Geology and Mining History of the Owens Valley and Mono Basin

Look up mono or mono- in Wiktionary, the free dictionary.

Mono often refers to:

• Anything single, e.g. as in monorail, a train system using a single rail, as opposed to the conventional two-rail system
• Monaural (or monophonic) sound, which uses a single channel, as opposed to stereophonic (or stereo) sound
• Infectious mononucleosis, also referred to as "glandular fever", "kissing disease" or "mono"

Mono may also refer to:

Biology[link]

• Monodactylus sebae, an animal species

Music[link]

• Mono (Japanese band), a Japanese post-rock band
• Mono (UK band), a UK pop duo
• Mono, a 1993 album by German band Fury in the Slaughterhouse
• Mono, a 2002 album recorded by Paul Westerberg (as "Grandpaboy") and included with his album Stereo
• Mono (song), is a song/single by Courtney Love released in 2004

Publications[link]

• Mono (Fanzine), Bradford alternative rock music fanzine

Places[link]

• Mono, California, former name of Mono Mills, California
• Mono County, California
• Mono Department, Benin
• Mono Lake, California
• Mono, Ontario, Canada
• Monó, the Hungarian name for Mânău village, Ulmeni town, Maramureş County, Romania
• Mono River, Togo
• Mono Island, Solomon Islands

People[link]

• Mono tribe, a tribe of Native Americans in California
  • Mono language (Native American), their language
• Mono people, ethnic group of the Democratic Republic of the Congo
  • Mono language (Congo), their language
• Mono language (Solomon Islands)
• Mono, an important character in the video game Shadow of the Colossus

Technology[link]

• Everson Mono, also known as Everson Mono Unicode, is an evenly spaced Unicode font (typeface)
• Mono (game), a shoot 'em up video game reminiscent of both Asteroids and Robotron: 2084
• Mono (software), an open source implementation of the Common Language Infrastructure (.NET)
• m0n0wall is an embedded firewall distribution of FreeBSD
• Monochrome BBS, a text-based multi-user bulletin board system

Other[link]

• Mono, international currency created by Sennacia banko
• Mono, type of rock climbing hand hold in which only one finger can be used
• Mono-, numerical prefix
• Monomorphism, type of morphism in universal algebra or category theory
• Monophonic
• "Monochrome Graffiti", type of graffiti style

See also[link]

• All pages with titles containing "Mono"
• Poly (disambiguation)
• Solo (music)
• Stereo

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

Oeschinen Lake in the Swiss Alps

A lake is a body of relatively still fresh or salt 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.^[1][2] 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.

Etymology, meaning, and usage of "lake"[link]

Lake Tahoe on the border of California and Nevada

The Caspian Sea is either the world's largest lake or a full-fledged sea.^[3]

The word lake comes from Middle English lake ("lake, pond, waterway"), from Old English lacu ("pond, pool, stream"), from Proto-Germanic *lakō ("pond, ditch, slow moving stream"), from the Proto-Indo-European root *leg'- ("to leak, drain"). Cognates include Dutch laak ("lake, pond, ditch"), Middle Low German lāke ("water pooled in a riverbed, puddle"), German Lache ("pool, puddle"), and Icelandic lækur ("slow flowing stream"). Also related are the English words leak and leach.

There is considerable uncertainty about defining the difference between lakes and ponds, and no current internationally accepted definition of either term across scientific disciplines or political boundaries exists.^{[citation needed]} For example, limnologists have defined lakes as water bodies which are simply a larger version of a pond, which can have wave action on the shoreline or where wind-induced turbulence plays a major role in mixing the water column. None of these definitions completely excludes ponds and all are difficult to measure. For this reason there has been increasing use made of simple size-based definitions to separate ponds and lakes. One definition of lake is a body of water of 2 hectares (5 acres) or more in area,^[4]:331[5] however others^[who?] have defined lakes as waterbodies of 5 hectares (12 acres) and above,^{[citation needed]} or 8 hectares (20 acres) and above^{[citation needed]} (see also the definition of "pond"). Charles Elton, one of the founders of ecology, regarded lakes as waterbodies of 40 hectares (99 acres) or more.^[6] The term lake is also used to describe a feature such as Lake Eyre, which is a dry basin most of the time but may become filled under seasonal conditions of heavy rainfall. In common usage many lakes bear names ending with the word pond, and a lesser number of names ending with lake are in quasi-technical fact, ponds.

In lake ecology the environment of a lake is referred to as lacustrine. Large lakes are occasionally referred to as "inland seas," and small seas are occasionally referred to as lakes, such as Lake Maracaibo, which is actually a bay.

Distribution of lakes[link]

The Seven Rila Lakes are a group of glacial lakes in the Bulgarian Rila mountains.

Wayanad District Kerala India

The majority of lakes on Earth are fresh water, and most lie in the Northern Hemisphere at higher latitudes. Canada, with a deranged drainage system has an estimated 63,504 lakes.^[7] Finland has 187,888 lakes of which 60,000 are large.^[8]

Most lakes have at least one natural outflow in the form of a river or stream, which maintain a lake's average level by allowing the drainage of excess water.^[9] Some lakes do not have a natural outflow and lose water solely by evaporation or underground seepage or both. They are termed endorheic lakes.

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

Evidence of extraterrestrial lakes exists; "definitive evidence of lakes filled with methane" was announced by NASA^{[citation needed]} as returned by the Cassini Probe observing the moon Titan, which orbits the planet Saturn.

Globally, lakes are greatly outnumbered by ponds: of an estimated 304-million standing water bodies worldwide, 91 percent are 1 hectare (2.5 acres) or less in area (see definition of ponds).^[10] Small lakes are also much more numerous than large lakes: in terms of area, one-third of the world's standing water is represented by lakes and ponds of 10 hectares (25 acres) or less.^{[citation needed]} However, large lakes account for much of the area of standing water with 122 large lakes of 1,000 square kilometres (390 sq mi, 100,000 ha, 247,000 acres) or more representing about 29 percent of the total global area of standing inland water.^{[citation needed]}

Origin of natural lakes[link]

A portion of the Great Salt Lake in Utah, United States

Salt crystals, on the shore of Lake Urmia, Iran

There are a number of natural processes that can form lakes. A recent tectonic uplift of a mountain range can create bowl-shaped depressions that accumulate water and form lakes. The advance and retreat of glaciers can scrape depressions in the surface where water accumulates; such lakes are common in Scandinavia, Patagonia, Siberia and Canada. The most notable examples are probably the Great Lakes of North America.

Lakes can also form by means of landslides or by glacial blockages. An example of the latter occurred during the last ice age in the U.S. state of Washington, when a huge lake formed behind a glacial flow; when the ice retreated, the result was an immense flood that created the Dry Falls at Sun Lakes, Washington.

Salt lakes (also called saline lakes) can form where there is no natural outlet or where the water evaporates rapidly and the drainage surface of the water table has a higher-than-normal salt content. Examples of salt lakes include Great Salt Lake, the Aral Sea and the Dead Sea.

Small, crescent-shaped lakes called oxbow lakes can form in river valleys as a result of meandering. The slow-moving river forms a sinuous shape as the outer side of bends are eroded away more rapidly than the inner side. Eventually a horseshoe bend is formed and the river cuts through the narrow neck. This new passage then forms the main passage for the river and the ends of the bend become silted up, thus forming a bow-shaped lake.

Crater lakes are formed in volcanic craters and calderas which fill up with precipitation more rapidly than they empty via evaporation. Sometimes the latter are called caldera lakes, although often no distinction is made. An example is Crater Lake in Oregon, located within the caldera of Mount Mazama. The caldera was created in a massive volcanic eruption that led to the subsidence of Mount Mazama around 4860 BC.

Gloe Lakes are freshwater lakes that have emerged when the water they consists of has been separated, not considerably long before, from the sea as a consequence of post-glacial rebound.

Some lakes, such as Lake Jackson in Florida, USA, come into existence as a result of sinkhole activity.

Lake Vostok is a subglacial lake in Antarctica, possibly the largest in the world. The pressure from the ice atop it and its internal chemical composition mean that, if the lake were drilled into, a fissure could result that would spray somewhat like a geyser.

Most lakes are geologically young and shrinking since the natural results of erosion will tend to wear away the sides and fill the basin. Exceptions are those such as Lake Baikal and Lake Tanganyika that lie along continental rift zones and are created by the crust's subsidence as two plates are pulled apart. These lakes are the oldest and deepest in the world. Lake Baikal, which is 25-30 million years old, is deepening at a faster rate than it is being filled by erosion and may be destined over millions of years to become attached to the global ocean. The Red Sea, for example, is thought to have originated as a rift valley lake.

Types of lakes[link]

Many lakes can have tremendous cultural importance. The West Lake of Hangzhou has inspired romantic poets throughout the ages, and has been an important influence on garden designs in China, Japan and Korea.^[11]

One of the many artificial lakes in Arizona at sunset.

The crater lake of Volcán Irazú, Costa Rica.

These kettle lakes in Alaska were formed by a retreating glacier.

Ephemeral 'Lake Badwater', a lake only noted after heavy winter and spring rainfall, Badwater Basin, Death Valley National Park.

• Periglacial lake: 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 lake: 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, such as a kettle lake.
• Artificial lake: 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 like Hirakud Dam in India.
• Endorheic lake, 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 lake: 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 lake: 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 or sag pond: 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 lake: A lake which is formed under the surface of the Earth's crust. Such a lake may be associated with caves, aquifers or springs.
• Crater lake: 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 lake: 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.
• Ephemeral lake, intermittent lake, or seasonal lake: A seasonal 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 lake: A lake which forms in a depression created by the activity of the winds.
• Vlei, in South Africa, shallow lakes which vary considerably with seasons.
• Epitshelf Lakes, unique lakes which exist on top of a dense saltwater body and are surrounded by ice. These are mostly found in the Arctic.

Characteristics[link]

Lake Päijänne is one of tens of thousands of lakes in Finnish Lakeland.

Lake Mapourika, New Zealand

Lakes have numerous features in addition to lake type, such as drainage basin (also known as catchment area), inflow and outflow, nutrient content, dissolved oxygen, pollutants, pH, and sedimentation.

Changes in the level of a lake are controlled by the difference between the input and output compared to the total volume of the lake. Significant input sources are precipitation onto the lake, runoff carried by streams and channels from the lake's catchment area, groundwater channels and aquifers, and artificial sources from outside the catchment area. Output sources are evaporation from the lake, surface and groundwater flows, and any extraction of lake water by humans. As climate conditions and human water requirements vary, these will create fluctuations in the lake level.

Lakes can be also categorized on the basis of their richness in nutrients, which typically affect plant growth. Nutrient-poor lakes are said to be oligotrophic and are generally clear, having a low concentration of plant life. Mesotrophic lakes have good clarity and an average level of nutrients. Eutrophic lakes are enriched with nutrients, resulting in good plant growth and possible algal blooms. Hypertrophic lakes are bodies of water that have been excessively enriched with nutrients. These lakes typically have poor clarity and are subject to devastating algal blooms. Lakes typically reach this condition due to human activities, such as heavy use of fertilizers in the lake catchment area. Such lakes are of little use to humans and have a poor ecosystem due to decreased dissolved oxygen.

Due to the unusual relationship between water's temperature and its density, lakes form layers called thermoclines, layers of drastically varying temperature relative to depth. Fresh water is most dense at about 4 degrees Celsius (39.2 °F) at sea level. When the temperature of the water at the surface of a lake reaches the same temperature as deeper water, as it does during the cooler months in temperate climates, the water in the lake can mix, bringing oxygen-starved water up from the depths and bringing oxygen down to decomposing sediments. Deep temperate lakes can maintain a reservoir of cold water year-round, which allows some cities to tap that reservoir for deep lake water cooling.

Lake Teletskoye, Siberia

Since the surface water of deep tropical lakes never reaches the temperature of maximum density, there is no process that makes the water mix. The deeper layer becomes oxygen starved and can become saturated with carbon dioxide, or other gases such as sulfur dioxide if there is even a trace of volcanic activity. 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. This is called a limnic eruption. An example is the disaster at Lake Nyos in Cameroon. The amount of gas that can be dissolved in water is directly related to pressure. As deep water surfaces, the pressure drops and a vast amount of gas comes out of solution. 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.

The material at the bottom of a lake, or lake bed, may be composed of a wide variety of inorganics, such as silt or sand, and organic material, such as decaying plant or animal matter. The composition of the lake bed has a significant impact on the flora and fauna found within the lake's environs by contributing to the amounts and the types of nutrients available.

A paired (black and white) layer of the varved lake sediments correspond to a year. During winter, when organisms die, carbon is deposited down, resulting to a black layer. At the same year, during summer, only few organic materials are deposited, resulting to a white layer at the lake bed. These are commonly used to track past paleontological events.

Limnology[link]

Lake Billy Chinook, Deschutes National Forest, Oregon.

Lake Cugun, Kirsehir, Turkey.

Limnology is the study of inland bodies of water and related ecosystems. Limnology divides lakes into three zones: the littoral zone, a sloped area close to land; the photic or open-water zone, where sunlight is abundant; and the deep-water profundal or benthic zone, where little sunlight can reach. The depth to which light can reach in lakes depends on turbidity, determined by the density and size of suspended particles. A particle is in suspension if its weight is less than the random turbidity forces acting upon it. These particles can be sedimentary or biological in origin and are responsible for the color of the water. Decaying plant matter, for instance, may be responsible for a yellow or brown color, while algae may cause greenish water. In very shallow water bodies, iron oxides make water reddish brown. Biological particles include algae and detritus. Bottom-dwelling detritivorous fish can be responsible for turbid waters, because they stir the mud in search of food. Piscivorous fish contribute to turbidity by eating plant-eating (planktonivorous) fish, thus increasing the amount of algae (see aquatic trophic cascade). The light depth or transparency is measured by using a Secchi disk, a 20-cm (8 in) disk with alternating white and black quadrants. The depth at which the disk is no longer visible is the Secchi depth, a measure of transparency. The Secchi disk is commonly used to test for eutrophication. For a detailed look at these processes, see lentic ecosystems.

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). In the daytime a lake can cool the land beside it with local winds, resulting in a sea breeze; in the night it can warm it with a land breeze.

How lakes disappear[link]

Lake Chad in a 2001 satellite image, with the actual lake in blue, and vegetation on top of the old lake bed in green.

Lake Badwater, February 9, 2005. Landsat 5 satellite photo.

Badwater Basin dry lake, February 15, 2007. Landsat 5 satellite photo.

The lake may be infilled with deposited sediment and gradually become a wetland such as a swamp or marsh. Large water plants, typically totos, 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, ephemeral lakes, or seasonal lakes and can be found in karstic terrain. A prime example of an intermittent lake is Lake Cerknica in Slovenia or Lag Prau Pulte in Graubünden. Other intermittent lakes are only the result of above-average precipitation in a closed, or endorheic basin, usually filling dry lake beds. This can occur in some of the driest places on earth, like Death Valley. This occurred in the spring of 2005, after unusually heavy rains.^[12] The lake did not last into the summer, and was quickly evaporated (see photos to right). A more commonly filled lake of this type is Sevier Lake of west-central Utah.

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.^[13]

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.

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.

Extraterrestrial lakes[link]

Titan's north polar hydrocarbon seas and lakes as seen in a false-color Cassini synthetic aperture radar mosaic.

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.^{[citation needed]} Under current conditions this water would quickly freeze and sublimate 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.^[14]

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.

Notable lakes[link]

Round Tangle Lake, one of the Tangle Lakes, located 2,864 feet (873 m) above sea level in interior Alaska

• Lake Michigan-Huron is the largest lake by surface area: 117,350 km². It also has the longest lake coastline in the world: 8,790 km. If Huron and Michigan are considered two lakes, Lake Superior is the largest lake, with 82,414 km². However, Huron still has the longest coastline at 6,157 km (2980 km excluding the coastlines of its many inner islands). The world's smallest geological ocean, the Caspian Sea, at 394,299 km² has a surface area greater than the six largest freshwater lakes combined, and it's frequently cited as the world's largest lake.
• The deepest lake is Lake Baikal in Siberia, with a bottom at 1,637 m. Its mean depth is also the greatest in the world (749 m).
  It is also the world's largest lake by volume (23,600 km³, though smaller than the Caspian Sea at 78,200 km³), and the second longest (about 630 km from tip to tip).
• The longest lake is Lake Tanganyika, with a length of about 660 km (measured along the lake's center line).
  It is also the second largest by volume and second deepest (1,470 m) in the world, after lake Baikal.
• The world's oldest lake is Lake Baikal, followed by Lake Tanganyika (Tanzania).
• The world's highest lake, if size is not a criterion, may be the crater lake of Ojos del Salado, at 6,390 metres (20,965 ft).^[15]
• The highest large (greater than 250 square kilometers) freshwater lake in the world is the 290 km² Pumoyong Tso (Pumuoyong Tso), in the Tibet Autonomous Region of China, at 28-34N 90-24E, 5,018 metres (16,463 ft) above sea level.^[16]
• The world's highest commercially navigable lake is Lake Titicaca in Peru and Bolivia at 3,812 m (12,507 ft). It is also the largest freshwater (and second largest overall) lake in South America.
• The world's lowest lake is the Dead Sea, bordering Israel and Jordan at 418 m (1,371 ft) below sea level. It is also one of the lakes with highest salt concentration.
• Lake Huron has the longest lake coastline in the world: about 2980 km, excluding the coastline of its many inner islands.
• The largest island in a freshwater lake is Manitoulin Island in Lake Huron, with a surface area of 2,766 km². Lake Manitou, located on Manitoulin Island, is the largest lake on an island in a freshwater lake.
• The largest lake located on an island is Nettilling Lake on Baffin Island, with an area of 5,542 km² and a maximum length of 123 km.^[17]
• The largest lake in the world that drains naturally in two directions is Wollaston Lake.
• Lake Toba on the island of Sumatra is located in what is probably the largest resurgent caldera on Earth.
• The largest lake located completely within the boundaries of a single city is Lake Wanapitei in the city of Sudbury, Ontario, Canada. Before the current city boundaries came into effect in 2001, this status was held by Lake Ramsey, also in Sudbury.
• Lake Enriquillo in Dominican Republic is the only saltwater lake in the world inhabited by crocodiles.
• Lake Bernard, Ontario, Canada, claims to be the largest freshwater lake in the world with no islands.
• The largest lake in one country is Lake Michigan, in the U.S.A. However, it is sometimes considered part of Lake Michigan-Huron, making the record go to Great Bear Lake, Northwest Territories, in Canada, the largest lake within one jurisdiction.
• The largest lake on an island in a lake on an island is Crater Lake on Vulcano Island in Lake Taal on the island of Luzon, The Philippines.
• The northernmost named lake on Earth is Upper Dumbell Lake in the Qikiqtaaluk Region of Nunavut, Canada at a latitude of 82°28'N. It is located only 5.2 kilometers southwest of Alert, the northernmost settlement in the world. There are also several small lakes located north of Upper Dumbell Lake, but they are all unnamed and only appear on very detailed maps.

Largest by continent[link]

The largest lakes (surface area) by continent are:

• Australia – Lake Eyre (salt lake)
• Africa – Lake Victoria, also the third-largest freshwater lake on Earth. It is one of the Great Lakes of Africa.
• Antarctica – Lake Vostok (subglacial)
• Asia – Lake Baikal (if the Caspian Sea is considered a lake, it is the largest in Eurasia, but is divided between the two geographic continents)
• Oceania – Lake Eyre when filled; the largest permanent (and freshwater) lake in Oceania is Lake Taupo.
• Europe – Lake Ladoga, followed by Lake Onega, both located in northwestern Russia.
• North America – Lake Michigan-Huron, which is hydrologically a single lake. However, lakes Huron and Michigan are often considered separate lakes, in which case Lake Superior would be the largest.
• South America – Lake Titicaca, which is also the highest navigable body of water on Earth at 3,821 m above sea level. The much larger Lake Maracaibo is considered by some to be the second-oldest lake on Earth, but since it lies at sea level and nowadays is a contiguous body of water with the sea, others consider that it has turned into a bay.

See also[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Lakes

Look up lake in Wiktionary, the free dictionary.

• Lakes Database
• Lake Classification Systems
• World's Most Beautiful Lakes – slideshow by The Huffington Post