(from Latin laus) is a terrain feature (or physical feature), a body of liquid on the surface of a world that is localized to
the bottom of basin (another
type of landform or terrain feature; that is, it is not global) and
moves slowly if it moves at all. Another definition is, a
body of fresh or salt water of considerable size that is surrounded
by land. On Earth, a body of water is considered a lake
when it is inland, not part of the ocean, is
larger and deeper than a pond, and is fed by a
river. The only world other than Earth known to harbor
lakes is Titan, Saturn's largest moon,
which has lakes of ethane, most likely mixed
with methane. It is not known if
Titan's lakes are fed by rivers, though Titan's surface is carved
by numerous river beds.
Natural lakes on Earth are generally found in mountainous areas,
, and areas with ongoing or
. Other lakes are found in
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.
Meaning and usage of "lake"
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. For example, limnologists
have defined lakes as waterbodies
which are simply a larger version of a pond or which 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 or more in area, however others have defined
lakes as waterbodies of and above, or and above (see also the
definition of "pond"
, one of the
founders of ecology
, regarded lakes as
waterbodies of or more. 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 the name, as in Green
Lake, while larger lakes often invert the word order, as
Ontario, at least in North America.
lake in the English Lake
District is actually
called a lake; other than Bassenthwaite Lake, the others are all "meres" or "waters". Only six bodies of
water in Scotland are known as
lakes (the others are lochs): the Lake of
Lake of the
Lake, Cally Lake near Gatehouse of Fleet, the saltwater Manxman's Lake at Kirkcudbright Bay, and The Lake at Fochabers.
only the Lake of Menteith and Cally Lake are natural bodies of
Distribution of lakes
majority of lakes on Earth are fresh
water, and most lie in the Northern Hemisphere at higher latitudes.
60% of the world's lakes are in Canada; this is
because of the deranged
drainage system that dominates the country.
Finland is known as
The Land of the Thousand Lakes, (actually there are
187,888 lakes in Finland, of which 60,000 are large), and the
U.S. state of Minnesota is known as The Land of Ten Thousand
Lakes. The license plates of the Canadian province of Manitoba used to claim "100,000 lakes" as one-upmanship on
Minnesota, whose license plates boast of its "10,000
Most lakes have a natural outflow in the form of a river
or stream, but some do not and lose water solely
by evaporation or underground seepage or both. They are termed
lakes (see below).
Many lakes are artificial and are constructed for hydro-electric
power generation, recreational
use, or domestic water
Evidence of extraterrestrial lakes exists; "definitive evidence of
lakes filled with methane" was announced by NASA as returned by the
, which orbits the planet
Globally, lakes are greatly outnumbered by ponds: of an estimated
304 million standing water bodies worldwide, 91% are or less in
area (see definition of ponds
) . Small lakes
are also much more numerous than big lakes: in terms of area, one
third of the world's standing water is represented by lakes and
ponds of or less. However, large lakes contribute
disproportionately to 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% of the total global area of standing inland
Origin of natural lakes
There are a number of natural processes that can form lakes. A
uplift of a mountain range
can create bowl-shaped depressions that accumulate water and form
advance and retreat of glaciers can scrape depressions in the
surface where water accumulates; such lakes are common in Scandinavia, Patagonia,
Canada. The most notables examples are probably the
Lakes of North
Lakes can also form by means of landslides or by glacial blockages.
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.
lakes) can form where there is
no natural outlet or where the water evaporates rapidly and the
drainage surface of the water table
a higher-than-normal salt
content. Examples of salt
lakes include Great Salt
Lake, the Aral
Sea, and the Dead
Small, crescent-shaped lakes called oxbow
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
are formed in volcanic craters
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.
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
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
lakes, such as Lake Jackson in Florida, USA, come into existence as a result of
Lake Vostok is a subglacial lake
in Antarctica, possibly the largest in the world.
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
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
- 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.
- 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
- 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
Eyre in central Australia or
Sea in central Asia, are most common in desert
- 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 spring.
- 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 mineral. 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
- 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: A seasonal lake
that exists as a body of water
during only part of the year.
- Intermittent lake: A lake with
no water during a 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
- 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
Lakes have numerous features in addition to lake type, such as
(also known as
catchment area), inflow and outflow, nutrient
content, dissolved oxygen
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
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 affects 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
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
, lakes form layers called thermoclines
, layers of drastically varying
temperature relative to depth. Fresh water is most dense at about 4
(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
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
up the deep layers and can release a vast cloud of toxic gases
which lay trapped in solution in the colder water at the bottom of
the lake. This is called a limnic
. An example of such a release is the disaster at Lake Nyos in
The amount of gas that can be dissolved in
water is directly related to pressure. As the previously deep water
surfaces, the pressure drops, and a vast amount of gas comes out of
solution. Under these circumstances even carbon dioxide is toxic
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
, 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
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
paleontological events which happened in the past.
is the study of inland bodies of
water and related ecosystems. Limnology divides lakes into three
zones: the littoral zone
sloped area close to land; the photic
or open-water zone
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
, determined by the density and
size of suspended particle
particle is in suspension
its weight is less than the random turbidity forces
it. These particles can be sedimentary
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
Bottom-dwelling detritivorous fish
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
). The light depth or transparency is measured by using
a Secchi disk
, a 20-centimeter
(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
A lake moderates the surrounding region's temperature
has a very high specific heat capacity
). In the daytime, a lake can cool
the land beside it with local winds
in a sea breeze
; in the night, it can
warm it with a land breeze
How lakes disappear
A lake may be infilled with deposited sediment and gradually become
such as a swamp
. Large water
plants, typically reed
, 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
. In lowland river valleys, where a river can
, the presence of peat is explained
by the infilling of historical oxbow
. In the very last stages of succession
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
Beloye vanished in a matter of minutes.
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
("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.
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.
Sea is described as being "murdered" by the diversion
for irrigation of the rivers feeding it.
At present the surface of the planet Mars
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
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
's small moon Io
is volcanically active due to tidal stresses,
and as a result sulfur
accumulated on the surface. Some photographs taken during the
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
for "lake") because they were thought by early
astronomers to be lakes of water.
- 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.
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).
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.
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
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).
longest lake is Lake Tanganyika, with a length of about 660 km (measured along
the lake's center line).
It is also the second deepest in the world (1,470 m)
after lake Baikal.
world's oldest lake is Lake Baikal, followed by Lake Tanganyika (Tanzania).
world's highest lake is the crater lake of
Salado, at . The Lhagba
Pool in Tibet at comes second.
highest large freshwater lake in the world is Lake
Manasarovar in Tibet
Autonomous Region of China.
world's highest commercially navigable lake is
Peru and Bolivia at . It is also the largest freshwater (and
second largest overall) lake in South
world's lowest lake is the Dead Sea, bordering Israel, Jordan at
418 m (1,371 ft) below sea level. It is also one
of the lakes with highest salt
Huron has the longest lake coastline in
the world: about 2980 km, excluding the coastline of its many
largest island in a freshwater lake is
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.
largest lake located on an island is Nettilling Lake on Baffin
Island, with an area of 5542 km² and a maximum length of
123 km. .
largest lake in the world that drains naturally in two directions
Toba on the island of Sumatra is located in what is probably the largest
resurgent caldera on Earth.
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
Largest by continent
The largest lakes (surface area) by continent
- Australia - Lake Eyre (salt lake)
- Africa - Lake Victoria, also the third largest freshwater lake on Earth. It is one of the Great Lakes
- 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
- 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
Superior would be
- 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
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
- The Caspian
Sea is generally regarded by geographers, biologists and
a huge inland salt
lake. However, the Caspian large size means that for some
purposes it is better modeled as a sea.SCREW WIKIPEDIA
Geologically, the Caspian, Black, and Mediterranean seas are remnants of the
Ocean. Politically, the distinction between a sea and a lake
may affect how the Caspian is treated by international law.
- Statistics Finland
- Minnesota Driver and Vehicle Services
- Downing JA, Prairie YT, Cole JJ, Duarte CM, Tranvick LJ,
Striegel RG, McDowell WH, Kortelainen P, Melack JM, Middleburg JJ
(2006). The global abundance and size distribution of lakes, ponds
and impoundments. Limnology and Oceanography, 51: 2388-2397.
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- Andes Website - Information about Ojos del Salado
volcano, a high mountain in South America and the World's highest
- The Lake and Island Combination