Dictionary of Meaning
<<Back
Please select a letter:
A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
K |
L |
M |
N |
O |
P |
Q |
R |
S |
T |
U |
V |
W |
X |
Y |
Z |
0-9
Click here for Shopping
Lake
*** Shopping-Tip: Lake
{{otheruses}}
{| width="250" align="right"
|
image:Lake Clearwater-800px.jpg thumb|250px|thumb|Lake Clearwater, [[Ontario, Canada]]
Image:Manasbal.jpg right|thumb|250px|The Mansbal Lake in [[Jammu and Kashmir,
India]]
Image:swanson7802.jpg 250px|thumb|Massapequa Lake ([[New York|NY)]]
Image:LakeBaikal.png thumb|250px|[[Lake Baikal, the deepest and largest (by volume) freshwater lake.]]
|}
A '''lake''' is a body of water surrounded by land. The majority of lakes are
fresh water, and most lie in the
Northern Hemisphere at higher
latitudes. Large lakes are sometimes referred to as "inland
seas" and small seas are sometimes referred to as lakes.
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 (
swimming,
wind surfing,...), water supply, etc.
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
Minnesota is known as ''The Land of Ten Thousand Lakes''. The
Great Lakes of
North America originated in the
ice age.
Over 60% of the world's lakes are in
Canada; this is because of the
deranged drainage system that dominates the country.
Origin of natural lakes
Most lakes are young, as the natural results of erosion will tend to wear away one of the basin sides containing the lake. 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 lakes accumulate. Such lakes are common in
Scandinavia,
Siberia and
Canada.
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 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.
Saline lakes can form where there is no natural outlet or the water evaporates rapidly, and the drainage surface of the water table has a higher than normal
salt content. Examples of salt lakes include the
Great Salt Lake, the
Caspian Sea and the
Dead Sea.
Small, crescent-shaped lakes called
oxbow lakes can form in river valleys as the result of meandering. The slow-moving river forms a sinuous shape as the outer side of bends is torn away more rapidly than the inner side. Eventually a horseshoe bend is formed and the river cuts through the narrow neck. This gap now forms the main passage for the river and the ends of the bend become silted up.
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 on
geological fault lines. The
Crater Lake in
Oregon is a lake located within the
caldera of an extinct volcano.
Some lakes come into existence as a result of
sinkhole activity.
Characteristics
Image:Lake mapourika NZ.jpeg left|thumbnail|150px|[[Lake Mapourika,
New Zealand]]
The change in level of a lake is controlled by the difference between the sources of inflow and outflow, compared to the total volume of the lake. The 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 categorized on the basis of their richness of nutrients, which typically effects plant growth. Nutrient poor lakes are said to be ''oligotrophic'', and are generally clear, having a low concentration of plant life. ''Mesotropic'' 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. A ''hypertrophic'' lake is a water body that has been highly enriched with nutrients. These lakes typically have poor clarity and are subject to 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, and have a poor ecosystem.
Types of lakes
A
periglacial lake is one in which part of its margin is formed by an
ice sheet,
ice cap or
glacier, the ice having obstructed the natural
drainage of the land.
Image:Arizona_sunset.jpg thumb|300px|One of the many artificial lakes in [[Arizona at sunset.]]
A
subglacial lake is one which is permanently covered by
ice. They can occur under glaciers and ice caps or ice sheets. There are many such lakes, but
Lake Vostok in
Antarctica is by far the largest. The are kept
liquid because the overlying ice acts as a
thermal insulator retaining energy introduced to its underside by
friction, water percolating through crevasses, by the pressure from the
mass of the ice sheet above or by
geothermal heating below.
Because of the unusual relationship between water's temperature and its density, the water in lakes in temperate climates mixes twice a year. Fresh water is most dense at about 4 degrees Celsius. When the temperature of the water at the surface of a lake reaches the temperature at which water is most dense all the water in the lake can mix, bringing oxygen starved water up from the depths, and bringing oxygen down to decomposing sediments. When the density of surface water differs from that of the deeper water there is a marked barrier layer, the
thermocline, that prevents mixing. Deep Temperate lakes can maintain a reservoir of cold water year-round. The reservoir of deep, cold water allows cities to tap that reservoir for
deep lake water cooling.
Since the water of deep tropical lakes never reaches the temperature where water reaches its maximum density, there is no process that makes the water mix. The deeper layer becomes oxygen starved, and can become saturated with carbon dioxide, and possibly other gases, like sulfur dioxide, if there is even a trace of volcanic activity. Exceptional events, like earthquakes or landslides, which do cause mixing, that brings up the deep layers, can release a vast cloud of toxic gas. An example of a release as described is
Lake Nyos in
Cameroon. The amount of gas that can be dissolved in water is pressure related. As the water surfaces, and the pressure drops, a vast amount of gas cab comes out of solution. Under these circumstances even carbon dioxide is toxic. Carbon dioxide is heavier than air, and the released carbon dioxide flows down the river valley.
Artificial lakes
{{main|Reservoir (water)}}
A
Reservoir (water) reservoir (
French language French: ''réservoir'') is an artificial lake created by flooding land behind a
dam. Some of the world's largest lakes are reservoirs.
Artificial lakes can also be made deliberately by digging one or by flooding an open-pit
Mining mine.
Abiotic and biotic limnology
Image:Lake.jpg thumb|right|250px|Lake Billy Chinook, Deschutes National Forest, [[Oregon.]]
Limnology divides lakes in 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
Particle (ecology) 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. A sediment particle is in
Suspension (chemistry) suspension if its weight is less than the random turbidity
forces acting upon it. The turbidity is a decisive factor in the transparency of the water. Bottom-dwelling detritivorous
fish are responsible for turbid waters, because they stir the mud in search for food. Piscivorous fish eat plant-eating (planktonivorous) fish, thus increasing the number of algae (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. For a detailed look at these processes, see
Lentic System Ecology lentic system ecology.
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, the lake can cool the land beside it with
local winds, resulting in a
sea breeze; in the night, it can warm it, forming a
land breeze.
How lakes disappear
A lake may be infilled with deposited sediment, and gradually, the lake becomes a
wetland, such as a
swamp or
marsh. An important difference exists between lowland and highland lakes: lowland lakes are more placid, are less rocky/more sedimentary, have a less sloping bottom, and generally contain more plant life. Large water plants (typically
reed (plant) reeds) accelerate this closing process significantly because they trap sediment. Turbid lakes, and lakes with much plant-eating fish, tend to disappear slower. A "disappearing" lake (barely noticeable on a human timescale) typically has a water's edge with extensive plant mats. They become a new habitat for other plants (like
Sphagnum 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 (allowing the river to
meander), the presence of peat is explained by the closing of historical
oxbow lakes. In the very last stages of
succession, more
trees would grow in, eventually turning the wetland into a
forest.
Some lakes can also disappear seasonally; they are called
intermittent lakes and are typical of
Karst karstic terrain. A prime example of this is
Lake Cerknica in
Slovenia.
On June 3, 2005 in
Bolotnikovo,
Russia, a lake called White Lake vanished in a short period of time (minutes). News sources reported government officials theorized that this strange phenomena may have been caused by a shift on soil underneath the lake which drained water to channels leading to Oka River.
Neusiedler See, located in
Austria and
Hungary, dried up several times for a number years during the past centuries.
As of 2005, it is again rapidly losing water, giving rise to the fear that it will be completely dried up by
2010.
Extraterrestrial lakes
At present the surface of the planet
Mars (planet) Mars is too cold to permit pooling of liquid water on the surface. However geologic evidence appears to confirm that ancient lakes once formed on the surface. It is also possible that volcanic activity on Mars will occasionally melt the subsurface ice, forming large lakes. Under current conditions this water will quickly evaporate or freeze unless insulated in some manner, such as by a coating of volcanic ash.
Jupiter (planet) Jupiter's small moon
Io (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 spacecraft Galileo mission appear to show lakes of liquid sulfur on the surface.
There are dark basaltic plains on the
Moon, similar to
lunar mare lunar maria but smaller, that are called ''lacus'' (singular ''lacus'',
Latin for "lake"). They were once thought by early astronomers to be literal lakes.
Notable lakes
* The largest lake in the world by surface area is the
Caspian Sea. With a surface area of 394,299 km², it has a surface area greater than the next six largest lakes combined.
* The largest freshwater lake by surface area, and second largest by volume, is
Lake Superior with a surface area of 82,414 km². However,
Lake Huron and
Lake Michigan form a single hydrological system with surface area 117,350 km², sometimes designated
Lake Michigan-Huron. All these are part of the
Great Lakes of
North America.
* The deepest lake is
Lake Baikal in
Siberia, with a bottom at 1,637 m (5,371 ft.) and is the world's largest freshwater lake by volume.
* The world's oldest lake is
Lake Baikal, followed by
Lake Tanganyika (
Tanzania).
* The highest navigable lake is lake
Titicaca, at 3,821 m above sea level. It is also the second largest lake in
South America and largest freshwater lake (in
South America).
* The world's highest lake is Lhagba Pool in
Tibet at 6,368 m.
* The world's lowest lake is the
Dead Sea, currently (2005) 418 m (1,371 ft.) below sea level. It is also one of the lakes with highest
salt concentration.
* The largest freshwater-lake
island is
Manitoulin Island on
Lake Huron, with a surface area of 2,766 km².
Lake Manitou, located on Manitoulin Island, is the largest lake on a freshwater-lake island.
* The largest lake located on an island is
Nettilling Lake on
Baffin Island.
*
Lake Toba on the island of
Sumatra is located in what is probably the largest resurgent
caldera on
Earth.
* The largest freshwater lake in Europe is
Lake Ladoga, followed by
Lake Onega, both in north-western
Russia.
*
Lake Victoria is the largest lake in Africa, and second largest freshwater lake on
Earth by surface area. It is a part of the
Great Lakes of Africa.
*
Lake Maracaibo can be considered as the largest lake in South America. It however lies at sea level with a relatively wide opening to sea, so it is better described as a bay.
* The largest lake located completely within the boundaries of a single city is
Lake Wanapitei in the city of
Greater 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 is the only saltwater lake in the world inhabited by
crocodiles.
See also
*
List of lakes
*
List of world's largest lakes
*
Loch
*
Lough
*
Pond
*
Limnology
*
Lagoon
*
Geography
*
Tarn (lake) Tarn
this is edited
External links
{{commonscat|Lakes}}
{{wiktionary}}
-
Lakes Database
-
Lake Classification Systems
-
UKLakes Database
-
Midwest Lakes Policy Center
Category:Bodies of water
Category:Landforms
Category:Lakes
ar:بØيرة
bg:Езеро
br:Lenn (dour)
ca:Llac
cs:Jezero
cv:Кӳлĕ
da:Sø
de:See (Gewässer)
et:Järv
es:Lago
eo:Lago
fr:Lac
gl:Lago
ko:호수
io:Lago
id:Danau
it:Lago
he:×?×’×?
ka:ტბ�
mk:Езеро
nl:Meer (water)
ja:æ¹–
pl:Jezioro
pt:Lago
ro:Lac
ru:Озеро
simple:Lake
sl:Jezero
sr:Језеро
sv:Insjö
fi:Järvi
vi:Hồ (địa lý)
th:ทะเลสาบ
uk:Озеро
zh:湖泊
*** Shopping-Tip: Lake
