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101-411: Nitinat Lake is a large lake and inlet on the southwestern coast of Vancouver Island , British Columbia , Canada . The lake is about 150 km (93 mi) northwest by road from Victoria , BC's capital on the southern tip of Vancouver Island, and about 60 km (37 mi) southwest by road from the town of Lake Cowichan . The city of Port Alberni is about 80 km (50 mi) by road to

202-405: A "safe operational state". Alkalinity can be defined as the acid neutralizing capability of a body of water. Alkalinity in natural waters is largely due to bicarbonate , the strong conjugate base of the weak carbonic acid, that is the product of rock weathering. Bicarbonate has the ability to act as an acid or a base in water, making it a buffer to resist change from acidic or basic inputs into

303-409: A body of water from 2 hectares (5 acres) to 8 hectares (20 acres). Pioneering animal ecologist Charles Elton regarded lakes as waterbodies of 40 hectares (99 acres) 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

404-525: A body of water. Alkalinity is measured in the unit μeq L which is determined by the concentration of an ion per liter of water multiplied by the charge of the ion or by titration . Alpine lakes have been well studied in regard to acidification since the 1980s largely because of the seasonal patterns of alkalinity and pH changes that they naturally exhibit from precipitation and snowmelt. These lakes experience seasonally low alkalinity (and thus low pH), making them highly susceptible to acid precipitation as

505-680: A bright blue or brown color. The turbidity of alpine lakes plays a significant role in determining light availability for primary productivity and is heavily dependent on each lake's unique watershed. Circulation in alpine lakes can be caused by wind, river inflows, density currents , convection , and basin-scale waves. Steep topography characteristic of alpine lakes can partially shield them from wind generated by regional weather patterns. Therefore, smaller scale wind patterns generated by local topography, such as diurnal mountain breeze and katabatic wind , can be important in forcing circulation in alpine lakes. Wind patterns which vary spatially over

606-500: A comprehensive analysis of the origin of lakes and proposed what is a widely accepted classification of lakes according to their origin. This classification recognizes 11 major lake types that are divided into 76 subtypes. The 11 major lake types are: Tectonic lakes are lakes formed by the deformation and resulting lateral and vertical movements of the Earth's crust. These movements include faulting, tilting, folding, and warping. Some of

707-529: A deep layer of the lake never mixes with surface water) exist. Lake Cadagno , located in the Swiss Alps, is meromictic due to natural springs which constantly feed the bottom of the lake with dense, saline water. Other alpine lakes, such as Traunsee in Austria, have become meromictic due to salinization from anthropogenic activities such as mining. Recent studies suggest that climate change may impact

808-400: A distinction between clear alpine lakes and glacier-fed alpine lakes (lakes with inflow from melting glaciers). Clear alpine lakes have low concentrations of suspended sediment and turbidity which can be caused by a lack of erosion in the watershed. Glacier-fed lakes have much higher suspended sediment concentrations and turbidity due to inflow of glacial flour , resulting in opaqueness and

909-402: A form of organic lake. They form where a buildup of partly decomposed plant material in a wet environment leaves the vegetated surface below the water table for a sustained period of time. They are often low in nutrients and mildly acidic, with bottom waters low in dissolved oxygen. Artificial lakes or anthropogenic lakes are large waterbodies created by human activity . They can be formed by

1010-430: A glacier scours and depresses the bedrock as it moves downhill, and when the glacier retreats, the depressions are filled with glacier meltwater and run-off. These lakes are usually quite deep for this reason and some lakes that are several hundred meters deep may be caused by a process called overdeepening . In mountain valleys where glacier movement has formed circular depressions, cirque lakes (or tarns) may form when

1111-538: A higher perimeter to area ratio than other lake types. These form where sediment from a tributary blocks the main river. These form where sediment from the main river blocks a tributary, usually in the form of a levee . Lakes formed by other processes responsible for floodplain basin creation. During high floods they are flushed with river water. There are four types: 1. Confluent floodplain lake, 2. Contrafluent-confluent floodplain lake, 3. Contrafluent floodplain lake, 4. Profundal floodplain lake. A solution lake

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1212-510: A hypolimnion; accordingly, very shallow lakes are excluded from this classification system. Based upon their thermal stratification, lakes are classified as either holomictic , with a uniform temperature and density from top to bottom at a given time of year, or meromictic , with layers of water of different temperature and density that do not intermix. The deepest layer of water in a meromictic lake does not contain any dissolved oxygen so there are no living aerobic organisms . Consequently,

1313-428: A lake consists of a large area of standing water that occupies an extensive closed depression in limestone, it is also called a karst lake . Smaller solution lakes that consist of a body of standing water in a closed depression within a karst region are known as karst ponds. Limestone caves often contain pools of standing water, which are known as underground lakes . Classic examples of solution lakes are abundant in

1414-470: A large number of studies agree that small ponds are much more abundant than large lakes. For example, one widely cited study estimated that Earth has 304 million lakes and ponds, and that 91% of these are 1 hectare (2.5 acres) or less in area. Despite the overwhelming abundance of ponds, almost all of Earth's lake water is found in fewer than 100 large lakes; this is because lake volume scales superlinearly with lake area. Extraterrestrial lakes exist on

1515-560: A large seasonal cycle due to precipitation falling as snow and low glacier melt over the watershed in the winter contrasted with rainfall and increased glacier melt in summer. Alpine lakes are often situated in mountainous regions near or above the treeline which leads to steep watersheds with underdeveloped soil and sparse vegetation. A combination of cold climate over alpine watersheds, shading from steep topography, and low nutrient concentrations in runoff make alpine lakes predominantly oligotrophic . Different watershed characteristics create

1616-489: A natural outflow and lose water solely by evaporation or underground seepage, or both. These are termed endorheic lakes. Many lakes are artificial and are constructed for hydroelectric power generation, aesthetic purposes, recreational purposes, industrial use, agricultural use, or domestic water supply . The number of lakes on Earth is undetermined because most lakes and ponds are very small and do not appear on maps or satellite imagery . Despite this uncertainty,

1717-575: A pH less than 5.3 was characterized as having reached severe acidification. This analysis was repeated on 107 alpine lakes in the Central Alps with bedrock of silicic and ultrabasic rocks. These lakes had an alkalinity range from 155 to -23 microequiavlents per liter, suggesting how sensitive alpine lakes with similar bedrock might be to acidic rain. The Cascade Mountain Range extends from Northern California through Oregon and Washington. This region

1818-424: A range from 7.93–4.80 with 21% of the lakes having a pH below 6.00. The pH in this region was also found to be independent of altitude. A similar analysis was done on 207 lakes, resulting in an alkalinity range from -23 to 1372 μeq L and an average of 145 μeq L . The pH was also determined for these lakes, ranging from 4.6 to 9.2. Alpine lakes with a pH less than 6.0 had shown acidic effects on micro-organisms and

1919-446: A result of atmospheric pollutants . The water chemistry of alpine lakes is dominated by atmospheric deposition (transport of particles between the atmosphere) and catchment processes (drainage of precipitation). The weather patterns of alpine lakes include large periods of snowmelt which has extended contact with soil and rock resulting in increased alkalinity. Weathering of rocks that are calcareous or carbonate based ( limestone ) are

2020-403: 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. Their crescent shape gives oxbow lakes

2121-535: A result of the 1959 Hebgen Lake earthquake . Most landslide lakes disappear in the first few months after formation, but a landslide dam can burst suddenly at a later stage and threaten the population downstream when the lake water drains out. In 1911, an earthquake triggered a landslide that blocked a deep valley in the Pamir Mountains region of Tajikistan , forming the Sarez Lake . The Usoi Dam at

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2222-443: A significant role in determining vertical distribution of heat, dissolved chemicals, and biological communities. Most alpine lakes exist in temperate or cold climates characteristic of their high elevation, leading to a dimictic mixing regime. Dimictic lakes fully mix twice a year between periods of vertical stratification in the summer and winter. Summer stratification is caused by heating of surface waters, and winter stratification

2323-607: A stocking event between 1884 and 1941 of 1.8 million salmonids, mainly Rainbow trout ( Oncorhynchus mykiss ) and kokanee salmon ( O. nerka ). Other species introduced included brown trout ( Salmo trutta ), coho salmon ( O. kisutch ), cutthroat trout ( O. clarkii ), and steelhead salmon ( O. mykiss ). Introduced fish impact the limnetic and benthic communities, as they are the primary prey of non-native fish. Salamanders and newts found at Crater Lake also experienced encroachment on their native habitats and have been reduced or eliminated in numbers. These amphibians were also found in

2424-400: A unique diversity of invertebrates that are highly adapted to the colder and generally harsher conditions of these environments compared to lakes at lower altitudes. A few dominating species have adapted to the oligotrophic conditions and intense UV radiation, with chironomidae and oligochaeta comprising almost 70% of the community in two well-studied alpine lakes in northern Italy, and also

2525-422: A variation in density because of thermal gradients. Stratification can also result from a density variation caused by gradients in salinity. In this case, the hypolimnion and epilimnion are separated not by a thermocline but by a halocline , which is sometimes referred to as a chemocline . Lakes are informally classified and named according to the seasonal variation in their lake level and volume. Some of

2626-443: Is sag ponds . Volcanic lakes are lakes that occupy either local depressions, e.g. craters and maars , or larger basins, e.g. calderas , created by volcanism . Crater lakes are formed in volcanic craters and calderas, which fill up with precipitation more rapidly than they empty via either evaporation, groundwater discharge, or a combination of both. Sometimes the latter are called caldera lakes, although often no distinction

2727-403: Is a lake occupying a basin formed by surface dissolution of bedrock. In areas underlain by soluble bedrock, its solution by precipitation and percolating water commonly produce cavities. These cavities frequently collapse to form sinkholes that form part of the local karst topography . Where groundwater lies near the grounds surface, a sinkhole will be filled water as a solution lake. If such

2828-400: Is an efficient means for mixing in lakes and may play a significant role in homogenizing the water column between periods of stratification. Basin-scale waves, such as internal waves and seiches , can also drive circulation in alpine lakes. Internal seiches in an alpine lake have been observed with attendant velocities on the order of a few centimeters per second. Alpine lakes are home to

2929-424: Is an often naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land . Lakes lie completely on land and are separate from the ocean , although they may be connected with the ocean by rivers . Lakes, as with other bodies of water , are part of the water cycle , the processes by which water moves around

3030-527: Is caused by cooling of surface waters below the freshwater temperature of maximum density (approximately 4 °C (39 °F)). Seasonal ice cover reinforces the dimictic stratification cycle of alpine lakes by insulating the lake from wind and warm air in the spring when stratification is generally weaker. Some shallow alpine lakes can become fully mixed multiple times per year through episodic wind or cold inflow events and are therefore considered cold polymictic . A number of meromictic alpine lakes (in which

3131-618: Is composed of sedimentary and volcanic rocks, has heavy seasonal precipitation, and coniferous forests. The Alpine Lakes Wilderness Area in the Washington Cascades has over 700 lakes. Alkalinity for lakes in the Cascade region vary from as high as 400 μeq L-1 to as low as 57 μeq L , all of which are considered to be low alkalinity, and suggestive that they might be susceptible to acidification. The pH of these lakes ranged from 7.83 to 5.62, and in this region an acidified lake

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3232-571: Is considered having a pH below 4.7. The Cascade Range was further evaluated by subregions since the environments vary greatly. Lower alkalinity, 50–100 μeq L , was observed in regions with little soil and granite rocks, like that of Glacier Peak Wilderness and Mt. Rainier. Higher alkalinity, 200–400 μeq L , was observed in regions composed of basalt and andesite such as the Western Cascades. Paleoproxies are chemical or biological sources that serve as indicator data for some aspect of

3333-468: Is dammed behind an ice shelf that is attached to the coastline. They are mostly found in Antarctica. Fluvial (or riverine) lakes are lakes produced by running water. These lakes include plunge pool lakes , fluviatile dams and meander lakes. The most common type of fluvial lake is a crescent-shaped lake called an oxbow lake due to the distinctive curved shape. They can form in river valleys as

3434-452: Is made. An example is Crater Lake in Oregon , in the caldera of Mount Mazama . The caldera was created in a massive volcanic eruption that led to the subsidence of Mount Mazama around 4860 BCE. Other volcanic lakes are created when either rivers or streams are dammed by lava flows or volcanic lahars . The basin which is now Malheur Lake , Oregon was created when a lava flow dammed

3535-429: Is unknown but is estimated to be at least 2 million. Finland has 168,000 lakes of 500 square metres (5,400 sq ft) in area, or larger, of which 57,000 are large (10,000 square metres (110,000 sq ft) or larger). 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. Some lakes do not have

3636-931: The Andean lapwing . Another important alpine lake, Crater Lake located in Oregon, is home to several introduced fish species, native amphibians, and reptiles. The amphibians and reptiles that can be found in Crater Lake are the mazama newt , northwestern salamander , northwestern ribbed frog , northwestern toad, cascade frog, pacific tree frog , northern mountain lizard , pigmy horned toad , northern alligator lizard , and northwestern garter snake . Some alpine lakes do not hold any native vertebrate species and instead have grown their vertebrate communities through introduced species. Fish are commonly introduced by humans stocking lakes for recreational and competitive fishing. Crater Lake did not hold any vertebrate species before

3737-759: The Malheur River . Among all lake types, volcanic crater lakes most closely approximate a circular shape. Glacial lakes are lakes created by the direct action of glaciers and continental ice sheets. A wide variety of glacial processes create enclosed basins. As a result, there are a wide variety of different types of glacial lakes and it is often difficult to define clear-cut distinctions between different types of glacial lakes and lakes influenced by other activities. The general types of glacial lakes that have been recognized are lakes in direct contact with ice, glacially carved rock basins and depressions, morainic and outwash lakes, and glacial drift basins. Glacial lakes are

3838-554: The Proto-Indo-European root * leǵ- ('to leak, drain'). Cognates include Dutch laak ('lake, pond, ditch'), Middle Low German lāke ('water pooled in a riverbed, puddle') as in: de:Wolfslake , de:Butterlake , 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

3939-399: The density of water varies with temperature, with a maximum at +4 degrees Celsius, thermal stratification is an important physical characteristic of a lake that controls the fauna and flora , sedimentation, chemistry, and other aspects of individual lakes. First, the colder, denser water typically forms a layer near the bottom, which is called the hypolimnion . Second, normally overlying

4040-597: The Earth by extraterrestrial objects (either meteorites or asteroids ). Examples of meteorite lakes are Lonar Lake in India, Lake El'gygytgyn in northeast Siberia, and the Pingualuit crater lake in Quebec, Canada. As in the cases of El'gygytgyn and Pingualuit, meteorite lakes can contain unique and scientifically valuable sedimentary deposits associated with long records of paleoclimatic changes. In addition to

4141-420: The Earth. Most lakes are freshwater and account for almost all the world's surface freshwater, but some are salt lakes with salinities even higher than that of seawater . Lakes vary significantly in surface area and volume of water. Lakes are typically larger and deeper than ponds , which are also water-filled basins on land, although there are no official definitions or scientific criteria distinguishing

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4242-669: The Great Lakes of the U.S. and Canada are formed by the retreat of the Laurentide Ice Sheet during the last Ice Age which scoured the flat rock surface but are not in the alpine. Conversely, Lake Louise located in the Rocky Mountains was formed from glacial debris damming meltwater (i.e., a moraine lake) from the Victoria Glacier. The annual cycle of stratification and mixing in lakes plays

4343-571: The Lusatian Lake District, Germany. In India, Sudarshana Lake is a historical artificial lake located in the semi-arid region of Girnar, Gujarat, originally constructed during the reign of Chandragupta Maurya. See: List of notable artificial lakes in the United States Meteorite lakes, also known as crater lakes (not to be confused with volcanic crater lakes ), are created by catastrophic impacts with

4444-536: The annual cycles of stratification in alpine lakes. High altitude regions are experiencing changing seasonal weather patterns and faster warming than the global average. The duration of ice cover on alpine lakes is sensitive to these factors, and shorter ice cover duration has the potential to shift the mixing regime of lakes from dimictic to monomictic (one stratified and one fully mixed period each year). A change in mixing regime could fundamentally alter chemical and biological conditions such as nutrient availability and

4545-409: The base of food webs, are the primary accumulators of trace elements, which are then transferred up the food chain to fish or birds via predation. The seminal study that used chironomids as bioindicators due to their abundance in alpine lakes and variety of feeding habits (collectors, shredders, and predators) found that most trace element concentrations are within limits of sediment quality targets, with

4646-866: The base of the valley has remained in place for more than 100 years but the terrain below the lake is in danger of a catastrophic flood if the dam were to fail during a future earthquake. Tal-y-llyn Lake in north Wales is a landslide lake dating back to the last glaciation in Wales some 20000 years ago. Aeolian lakes are produced by wind action . These lakes are found mainly in arid environments, although some aeolian lakes are relict landforms indicative of arid paleoclimates . Aeolian lakes consist of lake basins dammed by wind-blown sand; interdunal lakes that lie between well-oriented sand dunes ; and deflation basins formed by wind action under previously arid paleoenvironments. Moses Lake in Washington , United States,

4747-620: The best kiteboarding and windsurfing in North America, attracting kiteboarders and windsurfers from around the world. There are many smaller lakes close to Nitinat Lake. Many of them, such as Hobiton Lake, Squalicum Lake, Tsuiat Lake, and Cheewhat Lake lie completely within Pacific Rim National Park Reserve, while others such as Doobah Lake and Sprise Lake lie between Pacific Rim National Park and Carmanah Walbran Provincial Park. Lake A lake

4848-486: The climate and can help reconstruct past regional climates and the future fate of alpine environments. Alpine lakes themselves are unique reservoirs of paleoclimate data, particularly for understanding climate in the late Quaternary , as they collect and store geomorphological and ecological data in their sediment . These records of the past allow for a better understanding of how alpine lakes have responded to climate variability. Thus, by understanding these mechanisms of

4949-485: The consumption of fossil fuels, has accelerated their rate of accumulation into alpine lake environments. Though essential to life in low concentrations, some trace elements begin to function as contaminants with over-accumulation. After being released into the atmosphere, trace elements can become soluble through biogeochemical processes and end up in sediment and then mobilized through weathering and runoff to enter alpine lake ecosystems. Benthic macroinvertebrates often at

5050-915: The courses of mature rivers, where a river channel has widened over a basin formed by eroded floodplains and wetlands . Some lakes are found in caverns underground . Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ice age . All lakes are temporary over long periods of time , as they will slowly fill in with sediments or spill out of the basin containing them. Artificially controlled lakes are known as reservoirs , and are usually constructed for industrial or agricultural use, for hydroelectric power generation, for supplying domestic drinking water , for ecological or recreational purposes, or for other human activities. 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

5151-518: The creation of lakes by the disruption of preexisting drainage networks, it also creates within arid regions endorheic basins that contain salt lakes (also called saline lakes). They form where there is no natural outlet, a high evaporation rate and the drainage surface of the water table has a higher-than-normal salt content. Examples of these salt lakes include Great Salt Lake and the Dead Sea . Another type of tectonic lake caused by faulting

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5252-622: The difference between lakes and ponds , and neither term has an internationally accepted definition across scientific disciplines or political boundaries. For example, limnologists have defined lakes as water bodies that 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, simple size-based definitions are increasingly used to separate ponds and lakes. Definitions for lake range in minimum sizes for

5353-536: The exception of criterion 3, the others have been accepted or elaborated upon by other hydrology publications. The majority of lakes on Earth are freshwater , and most lie in the Northern Hemisphere at higher latitudes . Canada , with a deranged drainage system , has an estimated 31,752 lakes larger than 3 square kilometres (1.2 sq mi) in surface area. The total number of lakes in Canada

5454-404: The exception of lead in both study lakes and zinc in one, and also concluded that trace element concentrations reflected the relative levels of pollution impacting each alpine lake in the study region of northern Italy. Another study, upon assessing the composition through time of chosen bioindicators and finding evidence for degraded water quality, concluded that the lake ecosystem had moved out of

5555-416: The extent of the lake may create regions of upwelling and downwelling . River inflow can induce circulation in alpine lakes through momentum carried directly into the lake by rivers or streams and through density currents. If the inflowing water is denser than the water at the surface of the lake (due to differences in temperature or sediment concentration), buoyancy drives the heavier inflowing water down

5656-613: The food web in Lake Tahoe. Nearby Cascade Lake in California, which is often closely studied with Lake Tahoe, does not have any introduced species due to highly restricted public access. Fish were also stocked in Lake Titicaca following the decimation of a native fish population after a fishing competition. Some studies have noted that recreational fishing of introduced species in alpine lakes may have negative effects on

5757-642: The high Andes is one species that is endemic, while others were introduced. Lake Titicaca is home to a wide variety of vertebrates, including the Titicaca water frog ( Telmatobious culeous) , and the endangered Titicaca grebe ( Rollandia microptera ) found only in the Titicaca basin. The basin is also home to a variety of bird species and is considered a Ramsar Site due to its ecological importance. Waterbird species include Chilean flamingo , greater yellowlegs , snowy egret , Andean coot , Andean gull , and

5858-422: The hypolimnion is a transition zone known as the metalimnion . Finally, overlying the metalimnion is a surface layer of warmer water with a lower density, called the epilimnion . This typical stratification sequence can vary widely, depending on the specific lake or the time of year, or a combination of both. The classification of lakes by thermal stratification presupposes lakes with sufficient depth to form

5959-907: The intentional damming of rivers and streams, rerouting of water to inundate a previously dry basin , or the deliberate filling of abandoned excavation pits by either precipitation runoff , ground water , or a combination of both. Artificial lakes may be used as storage reservoirs that provide drinking water for nearby settlements , to generate hydroelectricity , for flood management , for supplying agriculture or aquaculture , or to provide an aquatic sanctuary for parks and nature reserves . The Upper Silesian region of southern Poland contains an anthropogenic lake district consisting of more than 4,000 water bodies created by human activity. The diverse origins of these lakes include: reservoirs retained by dams, flooded mines, water bodies formed in subsidence basins and hollows, levee ponds, and residual water bodies following river regulation. Same for

6060-471: The karst regions at the Dalmatian coast of Croatia and within large parts of Florida . A landslide lake is created by the blockage of a river valley by either mudflows , rockslides , or screes . Such lakes are most common in mountainous regions. Although landslide lakes may be large and quite deep, they are typically short-lived. An example of a landslide lake is Quake Lake , which formed as

6161-763: The lake level. Alpine lake Alpine lakes are some of the most abundant types of lakes on Earth. In the Swiss Alps alone, there are nearly 1,000 alpine lakes, most of which formed after the Little Ice Age . As global temperatures continue to rise, more alpine lakes will be formed as glaciers recede and provide more run-off to surrounding areas, and existing lakes will see more biogeochemical changes and ecosystem shifts. An alpine lake's trophic state (i.e., level of biological productivity ) progresses with age (e.g., low productivity after formation and increased productivity with vegetation and soil maturity in

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6262-723: The lake's eastern shore lie Mt. Rosander and the foot of Carmanah Mountain, the eastern part of which is in Carmanah Walbran Provincial Park . Nitinat Lake drains into the Pacific Ocean just north of the Pacific entrance to the Strait of Juan de Fuca via the Nitinat Narrows, a narrow tidal passage about 3 km (1.9 mi) long. Tidal bores (ocean waves travelling up the lake) occur on

6363-428: The lake's physical features, including size and substrate, and environmental parameters, including temperature and ice-cover, define community composition and structure, with one study suggesting that temperature and altitude are the primary drivers, and another presenting evidence instead for heterogeneity in lake morphometry and substrate as the primary drivers. The latter, in particular an increase in rocky substratum,

6464-657: The largest lakes on Earth are rift lakes occupying rift valleys, e.g. Central African Rift lakes and Lake Baikal . Other well-known tectonic lakes, Caspian Sea , the Sea of Aral , and other lakes from the Pontocaspian occupy basins that have been separated from the sea by the tectonic uplift of the sea floor above the ocean level. Often, the tectonic action of crustal extension has created an alternating series of parallel grabens and horsts that form elongate basins alternating with mountain ranges. Not only does this promote

6565-698: The largest mountain range in Europe and home to some of the most well-known lakes. The bedrock in the Alps varies greatly and can be composed of granite, quartz, slate, dolomite, marble, limestone and much more. This diverse geological structure plays a role in the diverse alkalinity of each alpine lake. A study of 73 alpine lakes in the Eastern Alps determined that 85% of the lakes had low alkalinity values (< 200 μeq L ) with only two lakes having an alkalinity above 500 μeq L . This study also determined pH and found

6666-528: The layers of sediment at the bottom of a meromictic lake remain relatively undisturbed, which allows for the development of lacustrine deposits . In a holomictic lake, the uniformity of temperature and density allows the lake waters to completely mix. Based upon thermal stratification and frequency of turnover, holomictic lakes are divided into amictic lakes , cold monomictic lakes , dimictic lakes , warm monomictic lakes, polymictic lakes , and oligomictic lakes. Lake stratification does not always result from

6767-560: 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

6868-653: The magnetic properties of the lake sediments match those of the bedrock, it can be deduced that there was more glacier movement, i.e., cooler temperatures. Along with the sediments being "detrital" (bedrock weathering), the sediments are more coarse-grained indicating high glacial activity associated with the Pleistocene . Diatom assemblages reveal changes in benthic conditions and alkalinity which help infer changes in temperature and carbon dioxide concentrations over time. During periods of warmer temperatures, extended growing seasons led to more benthic plant growth which

6969-481: The mainland; lakes cut off from larger lakes by a bar; or lakes divided by the meeting of two spits. Organic lakes are lakes created by the actions of plants and animals. On the whole they are relatively rare in occurrence and quite small in size. In addition, they typically have ephemeral features relative to the other types of lakes. The basins in which organic lakes occur are associated with beaver dams, coral lakes, or dams formed by vegetation. Peat lakes are

7070-506: The major contributors of alkalinity to alpine lakes whereas alpine lakes in regions of granite and other igneous rocks have lower alkalinity due to slower kinetics of the weathering. Lower alkalinity indicates a lower ability to buffer the water from acidic or basic inputs so alpine lakes with low alkalinity are susceptible to acidic pollutants in the atmosphere. It is generally accepted that alpine lakes with alkalinity less than 200 unit μeq L are susceptible to acidification. The Alps are

7171-424: The mode of origin, lakes have been named and classified according to various other important factors such as thermal stratification , oxygen saturation, seasonal variations in lake volume and water level, salinity of the water mass, relative seasonal permanence, degree of outflow, and so on. The names used by the lay public and in the scientific community for different types of lakes are often informally derived from

7272-485: The moon Titan , which orbits the planet Saturn . The shape of lakes on Titan is very similar to those on Earth. Lakes were formerly present on the surface of Mars, but are now dry lake beds . In 1957, G. Evelyn Hutchinson published a monograph titled A Treatise on Limnology , which is regarded as a landmark discussion and classification of all major lake types, their origin, morphometric characteristics, and distribution. Hutchinson presented in his publication

7373-475: The more extreme temperature regimes characteristic of smaller bodies of water, selecting for a small subset of more robust species that end up thriving from less overall competition. Altitude may also affect community composition due to the change in availability of food resources. For example, at higher altitudes, alpine lakes experience shorter ice-free periods which places a limit on the amount of primary production and subsequent growth of food. In conclusion, both

7474-415: The morphology of the lakes' physical characteristics or other factors. Also, different cultures and regions of the world have their own popular nomenclature. One important method of lake classification is on the basis of thermal stratification, which has a major influence on the animal and plant life inhabiting a lake, and the fate and distribution of dissolved and suspended material in the lake. For example,

7575-406: The most numerous lakes in the world. Most lakes in northern Europe and North America have been either influenced or created by the latest, but not last, glaciation, to have covered the region. Glacial lakes include proglacial lakes , subglacial lakes , finger lakes , and epishelf lakes. Epishelf lakes are highly stratified lakes in which a layer of freshwater, derived from ice and snow melt,

7676-791: The names include: Lakes may be informally classified and named according to the general chemistry of their water mass. Using this classification method, the lake types include: A paleolake (also palaeolake ) is a lake that existed in the past when hydrological conditions were different. Quaternary paleolakes can often be identified on the basis of relict lacustrine landforms, such as relict lake plains and coastal landforms that form recognizable relict shorelines called paleoshorelines . Paleolakes can also be recognized by characteristic sedimentary deposits that accumulated in them and any fossils that might be contained in these sediments. The paleoshorelines and sedimentary deposits of paleolakes provide evidence for prehistoric hydrological changes during

7777-490: The narrows, the heights of which depend on tide heights, and these can be dangerous. The small First Nations village of Whyac lies on the southern lakeshore beside Nitinat Narrows and just north of the First Nations village of Clo-oose , also on the coast. The main volume of Nitinat Lake is salt water, with a thin layer of less dense fresh water floating on top. Nitinat Lake has consistent winds that offer some of

7878-499: The north. The southern end of the lake lies in Pacific Rim National Park Reserve , which also contains Nitinat Hill on the lake's northern shore and Nitinat Cone on the southern shore. Hitchie Creek Provincial Park and Nitinat Lake Ecological Reserve lie on opposite sides of the lakeshore about a third of the way from the lake's northern shore and the point where Nitinat River flows into the lake. On

7979-443: The only way to fix the problem is to completely eradicate the non-native fish species in the lakes in any way possible. These included using gill nets, electrofishing, and continued aggressive recreational fishing. Alpine lake invertebrates are arguably one of the most vulnerable communities of invertebrates to increasing temperatures associated with human-induced climate change, due to the expected increase in ice-free periods and to

8080-562: The organic-rich deposits of pre-Quaternary paleolakes are important either for the thick deposits of oil shale and shale gas contained in them, or as source rocks of petroleum and natural gas . Although of significantly less economic importance, strata deposited along the shore of paleolakes sometimes contain coal seams . 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

8181-405: The overall ecosystem. Bringing in non-native species, especially to fishless lakes, can also carry pathogens and bacteria, negatively impacting the invertebrate community already there. Studies of two fishless Italian alpine lakes, Dimon Lake and Balma Lake, found that introduced fish brought new viruses and bacteria that were harmful to the native amphibians in the water. The studies also showed that

8282-443: The past, better predictions can be made about the future response of alpine ecosystems to present-day climate change. The fraction of mineral phosphorus (P) to organic P within lake sediments can be used to determine if the sediment deposits are sourced from glaciers (higher mineral to organic P ratio) or debris slopes (lower mineral to organic P ratio). Therefore, the sediment P content can inform glacial activity and thus climate at

8383-404: The receding glacier, causes a depression, and then melts. Some alpine lakes reside in depressions formed from glaciers that existed during the last Ice Age yet are no longer proximate to any glaciers and are being sourced from snow, rain, or groundwater. Glacial alpine lakes have dramatically increased in number in recent years. From 1990 to 2018, the number of glacial lakes increased by 53% and

8484-422: The relatively small impact of human-changed land cover that other similar terrestrial-aquatic systems have already been subjected to. Cold- stenothermal species uniquely adapted to survive in only a small range of cold temperatures, and larger sexual reproducing species slower to reproduce than smaller, asexual species under perturbations, could both be negatively impacted. Melting glaciers are presumed to increase

8585-602: The size of the photic zone . Alpine lake ecosystems are undergoing unprecedented rates of change in community composition in relation to recent temperature increases and nutrient loading. Consistent monitoring can help identify, quantify and characterize this ecological impact. One such monitoring technique employs macroinvertebrates as bioindicators primarily to analyze the accumulation of trace elements associated with pollution and to, more generally, track changes in biological communities due to climate change. Trace elements can occur naturally, but industrialization, including

8686-458: The sizes of the alpine lakes that are glacier-fed, impacting the evidence size effect on community composition. Also, habitat structure could change in response to an increase in erosion from thawing permafrost, and lastly, an uptick in the frequency and magnitude of extreme weather events would increase water column turbidity, which is well-known to impact the processes of photosynthesis and respiration by increasing light attenuation and decreasing

8787-444: The slope of the lake bed or into the lake interior. Such density-driven flows have been recorded in alpine lakes with velocities reaching nearly 1 m/s. Heating and cooling of alpine lakes can cause surface waters to become more dense than the water in the interior of the lake. This results in a gravitationally unstable water column, and the dense water is pulled downward from the surface causing convection. This vertical circulation

8888-492: The stomach contents of fish stocked in Crater Lake, which has further reduced populations. Lake Tahoe , located between California and Nevada, also has several introduced fish species established in the basin due to recreational fishing, including lake trout ( Salvelinus namaycush ), rainbow trout, brown trout, bluegill ( Lepomis macrochirus ), carp ( Cyprinus caprio ), and others. Lake trout, along with an introduced freshwater shrimp, Mysis relicta , have drastically changed

8989-789: The surrounding watershed), but anthropogenic effects such as agriculture and climate change are rapidly affecting productivity levels in some lakes. These lakes are sensitive ecosystems and are particularly vulnerable to climate change due to the highly pronounced changes to ice and snow cover. Due to the importance of alpine lakes as sources of freshwater for agricultural and human use, the physical, chemical, and biological responses to climate change are being extensively studied. Commonly, alpine lakes are formed from current or previous glacial activity (called glacial lakes ) but could also be formed from other geological processes such as damming of water due to volcanic lava flows or debris, volcanic crater collapse, or landslides . Glacial lakes form when

9090-404: The thermal stratification, as well as the degree and frequency of mixing, has a strong control over the distribution of oxygen within the lake. Professor F.-A. Forel , also referred to as the "Father of limnology", was the first scientist to classify lakes according to their thermal stratification. His system of classification was later modified and improved upon by Hutchinson and Löffler. As

9191-523: The time the sediment was deposited. For instance, an alpine lake in the Coast Mountains of British Columbia revealed cooler and wetter conditions due to the increased trend in mineral-rich (glacial-derived) P sediments which agrees with other findings of cooling in the Holocene . Magnetic properties of the sediment in alpine lakes can also help infer glacial activity at a high resolution. When

9292-456: The times that they existed. There are two types of paleolake: Paleolakes are of scientific and economic importance. For example, Quaternary paleolakes in semidesert basins are important for two reasons: they played an extremely significant, if transient, role in shaping the floors and piedmonts of many basins; and their sediments contain enormous quantities of geologic and paleontologic information concerning past environments. In addition,

9393-465: The timing and duration of hypoxia in alpine lakes. In addition, the relatively small size and high altitude of alpine lakes may make them especially susceptible to changes in climate. The hydrology of an alpine lake's watershed plays a large role in determining chemical characteristics and nutrient availability. Sources of water inflow into alpine lakes include precipitation, melting snow and glaciers, and groundwater. Alpine lake inflow often has

9494-418: The total glacial lake area increased by 51% due to global warming . Alpine lakes adjacent to glaciers may also result in a positive feedback due to decreased albedo of water relative to ice, creating larger lakes and causing more glacial melt. Glacial alpine lakes differ from other glacier-formed lakes in that they occur at higher altitudes and mountainous terrain usually at or above timberline. For example,

9595-466: The two most prominent species (66% and 28%, respectively) in 28 alpine lakes in Austria. Phytoplankton populations are dominated by nanoplanktonic, mobile species including chrysophytes, dinoflagellates, and cryptophytes in the water column, with important contributions to photosynthesis also coming from the algae community attached to substrates, epilithon and epipelon. Viruses are also observed in alpine lakes at abundances of up to 3 x 10 ml , which nears

9696-641: The two. Lakes are also distinct from lagoons , which are generally shallow tidal pools dammed by sandbars or other material at coastal regions of oceans or large lakes. Most lakes are fed by springs , and both fed and drained by creeks and rivers , but some lakes are endorheic without any outflow, while volcanic lakes are filled directly by precipitation runoffs and do not have any inflow streams. Natural lakes are generally found in mountainous areas (i.e. alpine lakes ), dormant volcanic craters , rift zones and areas with ongoing glaciation . Other lakes are found in depressed landforms or along

9797-439: The upper range of the general observed abundances from 10 to 10 ml in aquatic systems. A study of 28 alpine lakes found that with increasing elevation, macroinvertebrate abundances increase in small lakes but decrease in larger lakes and community composition shifts with increasing elevation, towards a small number of specialized species. The increasing abundances in smaller lakes as elevation increases are thought to be due to

9898-459: The water becomes dammed. When damming occurs due to debris from the glacier movement, these lakes are called moraine lakes. These dams of debris can be very resilient or may burst, causing extreme flooding which poses significant hazards to communities in the alpine, especially in the Himalayas . Kettle lakes also form from glacier recession but are formed when a section of ice breaks off from

9999-467: The word pond , and a lesser number of names ending with lake are, in quasi-technical fact, ponds. One textbook illustrates this point with the following: "In Newfoundland, for example, almost every lake is called a pond, whereas in Wisconsin, almost every pond is called a lake." One hydrology book proposes to define the term "lake" as a body of water with the following five characteristics: With

10100-783: Was found to negatively impact abundance and species richness. All of these environmental parameters are likely to be impacted by climate change, with cascading effects on alpine lake invertebrate and microbial communities. The vertebrate community of alpine lakes is much more limited than invertebrate communities as harsh conditions have an increased impact on the organisms, but can include fish, amphibians, reptiles, and birds. Despite this, many alpine lakes can still host diverse species at these high elevations. These organisms have arrived in several ways through human introductions, ecological introductions, and some are endemic to their respective lakes. The Titicaca water frog in Lake Titicaca in

10201-617: Was originally a shallow natural lake and an example of a lake basin dammed by wind-blown sand. China's Badain Jaran Desert is a unique landscape of megadunes and elongated interdunal aeolian lakes, particularly concentrated in the southeastern margin of the desert. Shoreline lakes are generally lakes created by blockage of estuaries or by the uneven accretion of beach ridges by longshore and other currents. They include maritime coastal lakes, ordinarily in drowned estuaries; lakes enclosed by two tombolos or spits connecting an island to

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