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39-584: The Onyx River flows away from the ocean, an example of endorheic drainage , as the Wright Lower Glacier blocks the mouth of the Wright Valley. It has several tributaries , and there are multiple meteorological stations along the length of the river. Flow levels are highly variable, both during the day and between summers, with the river failing to reach the lake some years. In contrast, it can cause significant erosion in flood years, and

78-571: A crucial role as a keystone species by regulating phytoplankton and bacterioplankton levels. The Artemia species also serves as an intermediate host for helminth parasites that affect migratory water birds like flamingos, grebes, gulls, shorebirds, and ducks. Vertebrates in saline lakes include certain fish and bird species, though they are sensitive to fluctuations in salinity. Many saline lakes are also alkaline, which imposes physiological challenges for fish, especially in managing nitrogenous waste excretion. Fish species vary by lake; for instance,

117-580: A higher concentration of salt than sea water ; such lakes can also be termed hypersaline lake , and may also be pink lakes on account of their color. An alkalic salt lake that has a high content of carbonate is sometimes termed a soda lake . Salt lakes are classified according to salinity levels. The formation of these lakes is influenced by processes such as evaporation and deposition. Salt lakes face serious conservation challenges due to climate change, pollution and water diversion. The primary method of classification for salt lakes involves assessing

156-798: A large portion of Europe drains to the endorheic Caspian Sea, Europe's wet climate means it contains relatively few terminal lakes itself: any such basin is likely to continue to fill until it reaches an overflow level connecting it with an outlet or erodes the barrier blocking its exit. There are some seemingly endorheic lakes, but they are cryptorheic, being drained either through manmade canals , via karstic phenomena, or other subsurface seepage. A few minor true endorheic lakes exist in Spain (e.g. Laguna de Gallocanta , Estany de Banyoles ), Italy , Cyprus ( Larnaca and Akrotiri salt lakes) and Greece . Many small lakes and ponds in North Dakota and

195-709: A mountain range, cutting off water egress to the ocean. The inland water flows into dry watersheds where the water evaporates, leaving a high concentration of minerals and other inflow erosion products. Over time this input of erosion products can cause the endorheic lake to become relatively saline (a " salt lake "). Since the main outflow pathways of these lakes are chiefly through evaporation and seepage, endorheic lakes are usually more sensitive to environmental pollutant inputs than water bodies that have access to oceans, as pollution can be trapped in them and accumulate over time. Endorheic regions can occur in any climate but are most commonly found in desert locations. This reflects

234-523: A redistribution of water from these hydrologically landlocked basins such that endorheic water loss has contributed to sea level rise , and it is estimated that most of the terrestrial water lost ends up in the ocean. In regions such as Central Asia, where people depend on endorheic basins and other surface water sources to satisfy their water needs, human activity greatly impacts the availability of that water. Large endorheic regions in Africa are located in

273-466: Is a drainage basin that normally retains water and allows no outflow to other external bodies of water (e.g. rivers and oceans ); 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 . Endorheic regions contrast with open lakes (exorheic regions), where surface waters eventually drain into

312-710: Is a hyposaline lake. Mesosaline lakes have a salinity level ranging from 3 to 35 g/L. An example of a mesosaline lake is Redberry Lake in Saskatchewan, Canada . Hypersaline lakes possess salinities greater than 35 g/L, often reaching levels that can exceed 200 g/L. The extreme salinity levels create harsh conditions that limit the diversity of life, primarily supporting specialized organisms such as halophilic bacteria and certain species of brine shrimp . These lakes can have high concentrations of sodium salts and minerals, such as lithium, making such lakes vulnerable to mining interests. Hypersaline lakes can be found in

351-501: Is not limited to the Aral Sea; salt lakes around the world are shrinking due to excessive water diversion, dam construction, pollution, urbanization, and rising temperatures associated with climate change. The resulting declines cause severe disruptions to local ecosystems and biodiversity, degrades the environment, threatens economic stability, and displaces communities dependent on these lakes for resources and livelihood. In Utah, if

390-403: Is one such case, with annual precipitation of 850 mm (33 in) and characterized by waterlogged soils that require draining. Endorheic regions tend to be far inland with their boundaries defined by mountains or other geological features that block their access to oceans. Since the inflowing water can evacuate only through seepage or evaporation, dried minerals or other products collect in

429-627: The Bonneville flood . The Malheur / Harney lake system in Oregon is normally cut off from drainage to the ocean, but has an outflow channel to the Malheur River . This is presently dry, but may have flowed as recently as 1,000 years ago. Examples of relatively humid regions in endorheic basins often exist at high elevation. These regions tend to be marshy and are subject to substantial flooding in wet years. The area containing Mexico City

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468-720: The McMurdo Dry Valleys in Antarctica, where salinity can reach ≈440‰. Salt lakes form through complex chemical, geological, and biological processes, influenced by environmental conditions like high evaporation rates and restricted water outflow. As water carrying dissolved minerals ( sodium , potassium , and magnesium ) enters these basins, it gradually evaporates, concentrating these minerals until they precipitate as salt deposits. Then, specific ions interact under controlled temperatures, which leads to solid-solution formation and salt crystal deposition within

507-883: The Sahara Desert , the Sahel , the Kalahari Desert , and the East African Rift : Endorheic lakes exist in Antarctica's McMurdo Dry Valleys , Victoria Land , the largest ice-free area. Much of Western and Central Asia is a giant endorheic region made up of a number of contiguous closed basins. The region contains several basins and terminal lakes, including: Other endorheic lakes and basins in Asia include: Australia , being very dry and having exceedingly low runoff ratios due to its ancient soils, has many endorheic drainages. The most important are: Though

546-453: The French word endoréisme , which combines endo- ( Ancient Greek : ἔνδον éndon 'within') and ῥεῖν rheîn 'flow'. Endorheic lakes (terminal lakes) are bodies of water that do not flow into an ocean or a sea. Most of the water that falls to Earth percolates into the oceans and the seas by way of a network of rivers, lakes, and wetlands . Analogous to endorheic lakes is

585-474: The Great Salt Lake is not conserved, the state could face potential economic and public health crises, with consequences for air quality, local agriculture, and wildlife. According to “Utah’s Great Salt Lake Strike Team”, in order increase the lake's level within the next 30 years, see average inflows must increase by 472,00 acre-feet per year, which is about a 33% increase in the amount that has reached

624-544: The Northern Great Plains are endorheic, and some have salt encrustations along their shores. Some of Earth's ancient endorheic systems and lakes include: Salt lake A salt lake or saline lake is a landlocked body of water that has a concentration of salts (typically sodium chloride ) and other dissolved minerals significantly higher than most lakes (often defined as at least three grams of salt per liter). In some cases, salt lakes have

663-660: The Onyx River record since 1993. There is a small research shelter at Lake Vanda at its eastern end. Nearby is the Comprehensive Nuclear-Test-Ban Treaty Seismic station at Bull Pass . Since records have been kept, the Onyx River's flow season has shifted earlier and become longer. Endorheic basin An endorheic basin ( / ˌ ɛ n d oʊ ˈ r iː . ɪ k / EN -doh- REE -ik ; also endoreic basin and endorreic basin )

702-489: The Salton Sea is home to species such as carp, striped mullet, humpback sucker, and rainbow trout. Stratification in salt lakes occurs as a result of the unique chemical and environmental processes that cause water to separate into layers based on density . In these lakes, high rates of evaporation often concentrate salts, leading to denser, saltier water sinking to the lake's bottom, while fresher water remains nearer

741-493: The balance between tectonic subsidence and rates of evaporation and sedimentation. Where the basin floor is dropping more rapidly than water and sediments can accumulate, any lake in the basin will remain below the sill level (the level at which water can find a path out of the basin). Low rainfall or rapid evaporation in the watershed favor this case. In areas where rainfall is higher, riparian erosion will generally carve drainage channels (particularly in times of flood), or cause

780-460: The basin, eventually making the water saline and also making the basin vulnerable to pollution. Continents vary in their concentration of endorheic regions due to conditions of geography and climate. Australia has the highest percentage of endorheic regions at 21 per cent while North America has the least at five per cent. Approximately 18 per cent of the Earth's land drains to endorheic lakes or seas,

819-510: The chemical composition of the water within the lakes, specifically its salinity, pH , and the dominant ions present. Subsaline lakes have a salinity lower than that of seawater but higher than freshwater , typically ranging from 0.5 to 3 grams per liter (g/L). Hyposaline lakes exhibit salinities from 0.5 to 3 g/L, which allows for the presence of freshwater species along with some salt-tolerant aquatic organisms. Lake Alchichica in Mexico

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858-537: The class of bodies of water located in closed watersheds (endorheic watersheds) where the local topography prevents the drainage of water into the oceans and the seas. These endorheic watersheds (containing water in rivers or lakes that form a balance of surface inflows, evaporation and seepage) are often called sinks. Endorheic lakes are typically located in the interior of a landmass, far from an ocean, and in areas of relatively low rainfall. Their watersheds are often confined by natural geologic land formations such as

897-564: The degree that a lake no longer forms. Even most permanent endorheic lakes change size and shape dramatically over time, often becoming much smaller or breaking into several smaller parts during the dry season. As humans have expanded into previously uninhabitable desert areas, the river systems that feed many endorheic lakes have been altered by the construction of dams and aqueducts. As a result, many endorheic lakes in developed or developing countries have contracted dramatically, resulting in increased salinity, higher concentrations of pollutants, and

936-440: The disruption of ecosystems. Even within exorheic basins, there can be "non-contributing", low-lying areas that trap runoff and prevent it from contributing to flows downstream during years of average or below-average runoff. In flat river basins, non-contributing areas can be a large fraction of the river basin, e.g. Lake Winnipeg 's basin. A lake may be endorheic during dry years and can overflow its basin during wet years, e.g.,

975-783: The former Tulare Lake . Because the Earth's climate has recently been through a warming and drying phase with the end of the Ice Ages, many endorheic areas such as Death Valley that are now dry deserts were large lakes relatively recently. During the last ice age, the Sahara may have contained lakes larger than any now existing. Climate change coupled with the mismanagement of water in these endorheic regions has led to devastating losses in ecosystem services and toxic surges of pollutants. The desiccation of saline lakes produces fine dust particles that impair agriculture productivity and harm human health. Anthropogenic activity has also caused

1014-479: The lack of vertical mixing. Extremophiles , including specific bacteria and archaea , inhabit the hypersaline and oxygen-deficient zones at lower depths. Bacteria and archaea, for example, rely on alternative metabolic processes that do not depend on oxygen. These microorganisms play a critical role in nutrient cycling within salt lakes, as they break down organic material and release by-products that support other microbial communities. Due to limited biodiversity,

1053-400: The lake bed. This cycle of evaporation and deposition is the main process to the unique saline environment that characterizes a salt lake. Environmental factors further shape the composition and formation of salt lakes. Seasonal variations in temperature and evaporation drive mineral saturation and promote salt crystallization . In dry regions, water loss during warmer seasons concentrates

1092-428: The lake in recent years. Water conservation is viewed as being the most cost-effective and practical strategy to save salt lakes like the Great Salt Lake. Implementing strong water management policies, improving community awareness, and ensuring the return of water flow to these lakes are additional ways that may restore ecological balance. Other proposed methods of maintaining lake levels include cloud seeding and

1131-475: The lake's chemistry, supporting only specialized microbial life adapted to extreme environments with high salinity and low oxygen levels. The restricted vertical mixing limits nutrient cycling , creating a favorable ecosystem for halophiles (salt-loving organisms) that rely on these saline conditions for stability and balance. The extreme conditions within stratified salt lakes have a profound effect on aquatic life , as oxygen levels are severely limited due to

1170-548: The lake's salts. This creates a dynamic environment where seasonal shifts affect the salt lake's mineral layers, contributing to its evolving structure and composition. Groundwater rich in dissolved ions often serve as primary mineral sources that, combined with processes like evaporation and deposition, contribute to salt lake development. Salt lakes host a diverse range of animals, despite high levels of salinity acting as significant environmental constraints. Increased salinity worsens oxygen levels and thermal conditions, raising

1209-422: The largest of these land areas being the interior of Asia. In deserts, water inflow is low and loss to solar evaporation high, drastically reducing the formation of complete drainage systems . In the extreme case, where there is no discernible drainage system, the basin is described as arheic . Closed water flow areas often lead to the concentration of salts and other minerals in the basin. Minerals leached from

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1248-462: The ocean. In general, water basins with subsurface outflows that lead to the ocean are not considered endorheic; but cryptorheic . Endorheic basins constitute local base levels , defining a limit of the erosion and deposition processes of nearby areas. Endorheic water bodies include the Caspian Sea , which is the world's largest inland body of water. The term endorheic derives from

1287-417: The restrictive environment limits biodiversity , allowing only specially adapted life forms to survive, which creates unique, highly specialized ecosystems that are distinct from freshwater or less saline habitats. Salt lakes declined worldwide in recent years. The Aral Sea , once of the largest saline lakes with a surface area of 67,499 km in 1960, diminished to approximately 6,990 km in 2016. This trend

1326-698: The river. Skuas are also occasionally present in the area. The Onyx River is one of the many sites studied by the United States Antarctic Program of the National Science Foundation . Discharge data has been collected at the downstream gauge near Lake Vanda since 1969 and at the upstream gauge near the Wright Lower Glacier since 1972. The Antarctica New Zealand program once maintained a semi-permanent camp at Lake Vanda which has since been removed. NSF's McMurdo Long Term Ecological Research site has been maintaining

1365-462: The surface. These seasonal changes influence the lake's structure, making stratification more pronounced during warmer months due to increasing evaporation, which drives separation between saline and fresher layers in the lake, leading a phenomenon known as meromixis (meromictic state), primarily prevents oxygen from penetrating the deeper layers and create the hypoxic (low oxygen) or anoxic (no oxygen) zones. This separation eventually influenced

1404-599: The surrounding rocks are deposited in the basin, and left behind when the water evaporates. Thus endorheic basins often contain extensive salt pans (also called salt flats, salt lakes, alkali flats , dry lake beds, or playas). These areas tend to be large, flat hardened surfaces and are sometimes used for aviation runways , or land speed record attempts, because of their extensive areas of perfectly level terrain. Both permanent and seasonal endorheic lakes can form in endorheic basins. Some endorheic basins are essentially stable because climate change has reduced precipitation to

1443-495: The water level in the terminal lake to rise until it finds an outlet, breaking the enclosed endorheic hydrological system's geographical barrier and opening it to the surrounding terrain. The Black Sea was likely such a lake, having once been an independent hydrological system before the Mediterranean Sea broke through the terrain separating the two. Lake Bonneville was another such lake, overflowing its basin in

1482-433: The water's density and viscosity , which demands greater energy for animal movement. Despite these challenges, salt lakes support biota adapted to such conditions with specialized physiological and biochemical mechanisms. Common salt lake invertebrates include various parasites, with around 85 parasite species found in saline waters, including crustaceans and monogeneans . Among them, the filter-feeding brine shrimp plays

1521-408: Was rafted in 1984 by New Zealand researchers. At one time, the river's discharge reached 20 cubic metres per second (700 cu ft/s). There are no fish in the Onyx River, but it supports microscopic life , and the algal blooms can be quite extensive. The environment consists mainly of cyanobacteria and other algae. A few micro-animals ( nematodes , tardigrades , and rotifers ) live in

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