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Water salinity |
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Salinity levels |
Fresh water (< 0.05%) Brackish water (0.05–3%) Saline water (3–5%) Brine (> 5% up to 26%–28% max) |
Bodies of water |
A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing those of ocean water (3.5%, i.e. 35 grams per litre or 0.29 pounds per US gallon).
Specific microbial species can thrive in high-salinity environments [1] that are inhospitable to most lifeforms, [2] including some that are thought to contribute to the color of pink lakes. [3] [4] Some of these species enter a dormant state when desiccated, and some species are thought to survive for over 250 million years. [2]
The water in hypersaline lakes has great buoyancy due to its high salt content. [5]
Hypersaline lakes are found on every continent, especially in arid or semi-arid regions. [1]
In the Arctic, the Canadian Devon Ice Cap contains two subglacial lakes that are hypersaline. [6] In Antarctica, there are larger hypersaline water bodies, lakes in the McMurdo Dry Valleys such as Lake Vanda with salinity of over 35% (i.e. 10 times as salty as ocean water).[ citation needed ]
The most saline water body in the world is the Gaet'ale Pond, located in the Danakil Depression in Afar, Ethiopia. The water of Gaet'ale Pond has a salinity of 43%, making it the saltiest water body on Earth [7] (i.e. 12 times as salty as ocean water). Previously, it was considered that the most saline lake outside of Antarctica was Lake Assal, [8] in Djibouti, which has a salinity of 34.8% (i.e. 10 times as salty as ocean water). The best-known hypersaline lakes are the Dead Sea (34.2% salinity in 2010) and the Great Salt Lake in the state of Utah, US (5–27% variable salinity). The Dead Sea, dividing Israel and the West Bank from Jordan, is the world's deepest hypersaline lake. The Great Salt Lake, while having nearly three times the surface area of the Dead Sea, is shallower and experiences much greater fluctuations in salinity. At its lowest recorded water levels, it approaches 7.7 times the salinity of ocean water, but when its levels are high, its salinity drops to only slightly higher than that of the ocean. [9] [10] [11]
A halophile is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species.
Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water. It is usually measured in g/L or g/kg.
The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, particularly through lake-effect snow. It is a remnant of Lake Bonneville, a prehistoric body of water that covered much of western Utah.
An evaporite is a water-soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean deposits, and non-marine, which are found in standing bodies of water such as lakes. Evaporites are considered sedimentary rocks and are formed by chemical sediments.
An endorheic basin is a drainage basin that normally retains water and allows no outflow to other external bodies of water ; instead, the water drainage flows into permanent and seasonal lakes and swamps that equilibrate through evaporation. Endorheic basins are also called closed basins, terminal basins, and internal drainage systems.
Natural salt pans or salt flats are flat expanses of ground covered with salt and other minerals, usually shining white under the sun. They are found in deserts and are natural formations.
A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceed recharge. If the floor of a dry lake is covered by deposits of alkaline compounds, it is known as an alkali flat. If covered with salt, it is known as a salt flat.
A salt lake or saline lake is a landlocked body of water that has a concentration of salts and other dissolved minerals significantly higher than most lakes. In some cases, salt lakes have a higher concentration of salt than sea water; such lakes can also be termed hypersaline lakes, and may also be pink lakes on account of their colour. An alkalic salt lake that has a high content of carbonate is sometimes termed a soda lake.
Lake Assal is a crater lake in central-western Djibouti. It is located at the western end of Gulf of Tadjoura between Arta Region, and Tadjoura Region, touching Dikhil Region, at the top of the Great Rift Valley, some 120 km (75 mi) west of Djibouti city. Lake Assal is a saline lake that lies 155 m (509 ft) below sea level in the Afar Triangle, making it the lowest point on land in Africa and the third-lowest point on Earth after the Sea of Galilee and the Dead Sea. No outflow occurs from the lake, and due to high evaporation, the salinity level of its waters is 10 times that of the sea, making it the fifth most saline body of water in the world, behind Garabogazköl, Lake Retba, and Gaet'ale Pond. The salt in the lake is exploited under four concessions awarded in 2002 at the southeast end of the lake; the major share of production is held by Société d’Exploitation du Lac and Société d’Exploitation du Salt Investment S.A de Djibouti.
Don Juan Pond is a small and very shallow hypersaline lake in the western end of Wright Valley, Victoria Land, Antarctica, 9 kilometres (5.6 mi) west from Lake Vanda. It is wedged between the Asgard Range to the south and the Dais Range to the north. On the west end is a small tributary and a rock glacier. With a salinity level of 33.8%, Don Juan Pond is the saltiest of the Antarctic lakes. This salinity causes significant freezing-point depression, allowing the pond to remain liquid even at temperatures as low as −50 °C (−58 °F).
A brine pool, sometimes called an underwater lake, deepwater or brine lake, is a volume of brine collected in a seafloor depression. These pools are dense bodies of water that have a salinity that is typically three to eight times greater than the surrounding ocean. Brine pools are commonly found below polar sea ice and in the deep ocean. This below-sea ice forms through a process called brine rejection. For deep-sea brine pools, salt is necessary to increase the salinity gradient. The salt can come from one of two processes: the dissolution of large salt deposits through salt tectonics or geothermally-heated brine issued from tectonic spreading centers.
Blood Falls is an outflow of an iron(III) oxide–tainted plume of saltwater, flowing from the tongue of Taylor Glacier onto the ice-covered surface of West Lake Bonney in the Taylor Valley of the McMurdo Dry Valleys in Victoria Land, East Antarctica.
A soda lake or alkaline lake is a lake on the strongly alkaline side of neutrality, typically with a pH value between 9 and 12. They are characterized by high concentrations of carbonate salts, typically sodium carbonate, giving rise to their alkalinity. In addition, many soda lakes also contain high concentrations of sodium chloride and other dissolved salts, making them saline or hypersaline lakes as well. High pH and salinity often coincide, because of how soda lakes develop. The resulting hypersaline and highly alkalic soda lakes are considered some of the most extreme aquatic environments on Earth.
The Danakil Depression is the northern part of the Afar Triangle or Afar Depression in Ethiopia and Eritrea, a geological depression that has resulted from the divergence of three tectonic plates in the Horn of Africa. It is the third lowest lying location on the continent of Africa.
Brine rejection is a process that occurs when salty water freezes. The salts do not fit in the crystal structure of water ice, so the salt is expelled.
Mars habitability analogue environments on Earth are environments that share potentially relevant astrobiological conditions with Mars. These include sites that are analogues of potential subsurface habitats, and deep subsurface habitats.
Gaet'ale Pond is a small hypersaline lake located near the Dallol crater in the Danakil Depression. It is located over a hot spring of tectonic origin and has no apparent inlet or outlet streams. The water of Gaet'ale Pond has a salinity of 43%, making it the saltiest water body on Earth.
Dallol is a unique, terrestrial hydrothermal system around a cinder cone volcano in the Danakil Depression, northeast of the Erta Ale Range in Ethiopia. It is known for its unearthly colors and mineral patterns, and the very acidic fluids that discharge from its hydrothermal springs.
A sea ice brine pocket is an area of fluid sea water with a high salt concentration trapped in sea ice as it freezes. Due to the nature of their formation, brine pockets are most commonly found in areas below −2 °C (28 °F), where it is sufficiently cold for seawater to freeze and form sea ice. Though the high salinity and low light conditions of brine pockets create a challenging environment for marine mammals, brine pockets serve as a habitat for various microbes. Sampling and studying these pockets requires specialized equipment to accommodate the hypersaline conditions and subzero temperatures.