Lake Natron

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Lake Natron
Lake Natron (Tanzania) - 2017-03-06 (very early in rainy season) - satellite image (cropped).jpg
The lake on 6 March 2017 (satellite image)
Tanzania relief location map.svg
Red pog.svg
Lake Natron
Location Ngorongoro District, Arusha Region, Tanzania, Kajiado County, Kenya
Coordinates 02°25′S36°00′E / 2.417°S 36.000°E / -2.417; 36.000
Lake type saline
Basin  countries Tanzania
Surface elevation600 metres (2,000 ft) [1]
Official nameLake Natron Basin
Designated4 July 2001
Reference no.1080 [2]
The southern half of Lake Natron (top). Fault scarps and the Gelai Volcano can also be seen. Numerous near-white salt-crust "rafts" pepper the shallowest parts of the lake (inset). LakeNatron satellite labelled.jpg
The southern half of Lake Natron (top). Fault scarps and the Gelai Volcano can also be seen. Numerous near-white salt-crust "rafts" pepper the shallowest parts of the lake (inset).

Lake Natron is a salt or alkaline lake located in north Ngorongoro District of Arusha Region in Tanzania at the border with Kenya. It is in the Gregory Rift, which is the eastern branch of the East African Rift. [1] The lake is within the Lake Natron Basin, a Ramsar Site wetland of international significance. [2] It is the only regular breeding area for Africa's lesser flamingoes, although this habitat is not protected and is under threat from planned development projects.

Contents

Properties

This lake is fed principally by the Southern Ewaso Ng'iro River, which rises in central Kenya, and by mineral-rich hot springs. [1] It is quite shallow, less than three metres (9.8 ft) deep, and varies in width depending on its wat [3] er level. The lake is a maximum of 57 kilometres (35 mi) long and 22 kilometres (14 mi) wide. [1] The surrounding area receives irregular seasonal rainfall, mainly between December and May totalling 800 millimetres (31 in) per year. [1] Temperatures at the lake are frequently above 40 °C (104 °F). [1]

High levels of evaporation have left behind natron (sodium carbonate decahydrate) and trona (sodium sesquicarbonate dihydrate). The alkalinity of the lake can reach a pH of greater than 12. The surrounding bedrock is composed of alkaline, sodium-dominated trachyte lavas that were laid down during the Pleistocene period. The lavas have significant amounts of carbonate but very low calcium and magnesium levels. This has allowed the lake to concentrate into a caustic alkaline brine. [4]

The chemical properties of the water are known to calcify the bodies of any living thing that died in the lake, turning them to stone before they decompose. [5]

Flora

The colour of the lake is characteristic of those where very high evaporation rates occur. As water evaporates during the dry season, salinity levels increase to the point that salt-loving microorganisms begin to thrive. Such halophile organisms include some cyanobacteria that make their own food with photosynthesis as plants do. The red accessory photosynthesizing pigment in the cyanobacteria produces the deep reds of the open water of the lake and the orange colours of the shallow parts of the lake. The alkali salt crust on the surface of the lake is also often coloured red or pink by the salt-loving microorganisms that live there. Salt marshes and freshwater wetlands around the edges of the lake do support a variety of plants.

Fauna

Most animals find the lake's high temperature (up to 60 °C [140 °F]) and its high and variable salt content inhospitable. [6] Nonetheless, Lake Natron is home to some endemic algae, invertebrates, and birds. In the slightly less salty water around its margins, some fish can also survive.

The lake is the only regular breeding area in East Africa for the 2.5 million lesser flamingoes, whose status of "near threatened" results from their dependence on this one location. When salinity increases, so do cyanobacteria, and the lake can also support more nests. These flamingoes, the single large flock in East Africa, gather along nearby saline lakes to feed on Spirulina (a blue-green algae with red pigments). Lake Natron is a safe breeding location because its caustic environment is a barrier against predators trying to reach their nests on seasonally forming evaporite islands. Greater flamingoes also breed on the mud flats.

The lake has inspired the nature documentary The Crimson Wing: Mystery of the Flamingos by Disneynature, for its close relationship with the Lesser flamingoes as their only regular breeding area.

Two endemic fish species, the alkaline tilapias Alcolapia latilabris and A. ndalalani , also thrive in the waters at the edges of the hot spring inlets. A. alcalica is also present in the lake, but is not endemic.

Threats and preservation

The area around the salt lake is not inhabited but there is some herding and some seasonal cultivation. Threats to the salinity balance from increased siltation influxes will come from more projected logging in Natron watersheds and a planned hydroelectric power plant on the Ewaso Nyiro across the border in Kenya. Although development plans include constructions of a dike at the north end of the lake to contain the freshwater, the threat of dilution to this breeding ground may still be serious. There is no formal protection.

A new threat to Lake Natron is the proposed development of a soda ash plant on its shores. The plant would pump water from the lake and extract the sodium carbonate to convert to washing powder for export. Accompanying the plant would be housing for over 1000 workers, and a coal-fired power station to provide energy for the plant complex. In addition, there is a possibility the developers may introduce a hybrid brine shrimp to increase the efficiency of extraction.

According to Chris Magin, the RSPB's international officer for Africa, "The chance of the lesser flamingoes continuing to breed in the face of such mayhem are next to zero. This development will leave lesser flamingoes in East Africa facing extinction". Seventy-five percent of the world's lesser flamingoes are born on Lake Natron. [7] Currently a group of more than fifty East African conservation and environmental institutions are running a worldwide campaign to stop the planned construction of the soda ash factory by Tata Chemicals Ltd of Mumbai, India and National Development Corporation of Tanzania. The group working under the umbrella name Lake Natron Consultative Group is being co-ordinated by Ken Mwathe, Conservation Programme Manager at BirdLife International's Africa Secretariat.

As per communication in June 2008, Tata Chemicals shall not proceed with the Natron Project and further re-examination of this project will be subject to the Ramsar Wetlands plan, which is currently under preparation. [8]

Because of its unique biodiversity, Tanzania named the Lake Natron Basin to the Ramsar List of Wetlands of International Importance on 4 July 2001. The lake is also the World Wildlife Fund East African halophytics ecoregion.

Visiting the area

There are a number of campgrounds near the lake, which is also the base for climbing Ol Doinyo Lengai. Lake Natron has immense tourist attraction potentials that are important for ecotourism development. However, lack of a general management plan, inadequate funding at the operational level, lack of mechanisms to secure a fair distribution of ecotourism benefits, and poorly developed tourism infrastructural facilities to support diverse segments of tourists were identified as the main challenges associated with the management of ecotourism in the area. The lake can also be accessed from Shompole Conservancy Kenya. [9]

See also

Related Research Articles

In chemistry, an alkali is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases.

<span class="mw-page-title-main">Geography of Tanzania</span>

Tanzania comprises many lakes, national parks, and Africa's highest point, Mount Kilimanjaro. Northeast Tanzania is mountainous, while the central area is part of a large plateau covered in grasslands. The country also contains the southern portion of Lake Victoria on its northern border with Uganda and Kenya.

<span class="mw-page-title-main">Natron</span> Carbonate mineral

Natron is a naturally occurring mixture of sodium carbonate decahydrate (Na2CO3·10H2O, a kind of soda ash) and around 17% sodium bicarbonate (also called baking soda, NaHCO3) along with small quantities of sodium chloride and sodium sulfate. Natron is white to colourless when pure, varying to gray or yellow with impurities. Natron deposits are sometimes found in saline lake beds which arose in arid environments. Throughout history natron has had many practical applications that continue today in the wide range of modern uses of its constituent mineral components.

<span class="mw-page-title-main">Sodium carbonate</span> Chemical compound

Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils, and because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the Chlor-alkali process.

<span class="mw-page-title-main">Lesser flamingo</span> Species of bird

The lesser flamingo is a species of flamingo occurring in sub-Saharan Africa and western India. Birds are occasionally reported from further north, but these are generally considered vagrants.

<span class="mw-page-title-main">Lake Bogoria</span> Meromictic lake in Kenya

Lake Bogoria is a saline, alkaline lake that lies in a volcanic region in a half-graben basin south of Lake Baringo, Kenya, a little north of the equator. Lake Bogoria, like Lake Nakuru, Lake Elementeita, and Lake Magadi further south in the Rift Valley, and Lake Logipi to the north, is home at times to one of the world's largest populations of lesser flamingos. The lake is a Ramsar site and Lake Bogoria National Reserve has been a protected National Reserve since November 29, 1973. Lake Bogoria is shallow, and is about 34 km long by 3.5 km wide, with a drainage basin of 700 km2. It is Located in Baringo County.

<span class="mw-page-title-main">Lake Magadi</span> Lake Kajiado County, Kenya

Lake Magadi is the southernmost lake in the Kenyan Rift Valley, lying in a catchment of faulted volcanic rocks, north of Tanzania's Lake Natron. During the dry season, it is 80% covered by soda and is well known for its wading birds, including flamingos.

<span class="mw-page-title-main">Etosha Pan</span> Big endorheic salt ville in Namibias north

The Etosha Pan is a large endorheic salt pan, forming part of the Cuvelai-Etosha Basin in the north of Namibia. It is a vast hollow in the ground in which water may collect or in which a deposit of salt remains after water has evaporated. The 120-kilometre-long (75-mile-long) dry lakebed and its surroundings are protected as Etosha National Park, Namibia's second-largest wildlife park, covering 22,270 square kilometres (8,600 sq mi). The pan is mostly dry but after heavy rains it is flooded with a thin layer of water, which is heavily salted by the mineral deposits on the surface.

<span class="mw-page-title-main">Lake Nakuru</span> Alkaline lake in Rift valley

Lake Nakuru is one of the Rift Valley lakes, located at an elevation of 1,754 m (5,755 ft) above sea level. It lies to the south of Nakuru, in the rift valley of Kenya and is protected by Lake Nakuru National Park.

<span class="mw-page-title-main">Natrocarbonatite</span>

Natrocarbonatite is a rare carbonatite lava which erupts from the Ol Doinyo Lengai volcano in Tanzania within the East African Rift of eastern Africa. Natrocarbonatite lavas were first documented in 1962, by J. B. Dawson.

Lake Logipi is a saline, alkaline lake that lies at the northern end of the arid Suguta Valley in the northern Kenya Rift. It is separated from Lake Turkana by the Barrier volcanic complex, a group of young volcanoes that last erupted during the late 19th century or early 20th century. Saline hot springs discharge on the northern shoreline of Lake Logipi and at Cathedral Rocks near its southern limit, and help to maintain water at times of extreme aridity. During the rainy season, the lake is also recharged from the Suguta River which flows northward along the Suguta Valley, periodically forming a temporary lake that unites with Logipi.

<span class="mw-page-title-main">Lake Tsimanampetsotsa</span> Alkaline lake in Toliara Province

Lake Tsimanampetsotsa is a moderately alkaline lake in the Toliara Province, in the southwestern part of Madagascar. It is located at around 24°07′S43°45′E. The lake is protected within Tsimanampetsotsa National Park and it is also within a Ramsar site. The Ramsar site has a total area of 456 km2 (176 sq mi), while the surface of the lake is much smaller.

<span class="mw-page-title-main">Larnaca Salt Lake</span>

Larnaca Salt Lake is a complex network of four salt lakes of different sizes to the west of the city of Larnaca. The largest is lake Aliki, followed by lake Orphani, lake Soros and lake Spiro. They form the second largest salt lake in Cyprus after the Limassol Salt Lake. The total surface area of the lakes adds up to 2.2 km2 and being just off the road leading to Larnaca International Airport, the lake is one of the most distinctive landmarks of the area. It is considered one of the most important wetlands of Cyprus and it has been declared a Ramsar site, Natura 2000 site, Special Protected Area under the Barcelona Convention and an Important Bird Area (IBA). It is surrounded by halophytic scrubland and on its bank lies the Hala Sultan Tekke, one of the holiest of shrines within Ottoman Islam. It houses the tomb of Umm Haram, Muhammad's 'wet-nurse'.

<span class="mw-page-title-main">Chestnut-banded plover</span> Species of bird

The chestnut-banded plover is a species of bird in the family Charadriidae. This species has a large range, being distributed across Southern Africa. However, it occupies a rather small area.

<i>Alcolapia grahami</i> Species of fish

Alcolapia grahami, the Lake Magadi tilapia or Graham's cichlid, is a vulnerable species of fish in the family Cichlidae. It is specialised to live in hot, alkaline waters in springs and lagoons around hypersaline lakes.

<span class="mw-page-title-main">Soda lake</span> Lake that is strongly alkaline

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.

<span class="mw-page-title-main">Great Rift Valley, Kenya</span> Part of an intra-continental ridge system that runs through Kenya

The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. It is part of the Gregory Rift, the eastern branch of the East African Rift, which starts in Tanzania to the south and continues northward into Ethiopia. It was formed on the "Kenyan Dome" a geographical upwelling created by the interactions of three major tectonics: the Arabian, Nubian, and Somalian plates. In the past, it was seen as part of a "Great Rift Valley" that ran from Madagascar to Syria. Most of the valley falls within the former Rift Valley Province.

<span class="mw-page-title-main">Southern Ewaso Ng'iro</span> River in Kenya

The Southern Ewaso Ng'iro is a river in the Great Rift Valley in Kenya. It plays an important role in the ecology of Lake Natron, the main regular breeding site for near-threatened lesser flamingos. Changes to land use in the river's headwaters or in the marshes before the river enters the lake could have a serious impact on this species.

<span class="mw-page-title-main">Saharan halophytics</span> Ecoregion in North Africa

The Saharan halophytics ecoregion covers a series of low-lying evaporite depressions and wetlands spread across North Africa. The depressions are characteristically saline, variously chotts or sabkhas. The plants of the areas are highly specialized to survive in the harsh environment, with many being xerophytes (drought-tolerant) and halophytes (salt-tolerant). The biodiversity of the areas has been relatively protected by their isolation, and unsuitability of alkaline soil for farming.

<span class="mw-page-title-main">Pikrolimni (lake)</span> Endorheic, alkaline salt lake in Kilkis prefecture, Greece

Lake Pikrolimni is an endorheic, alkaline salt lake in Kilkis prefecture, Greece. It is located on the border of the Kilkis and Thessaloniki regional units, about 40 km northwest of Thessaloniki. The lake is hypersaline, has rather shallow waters (0.5–0.7 m) and a shoreline of about 8.5 km. The water surface area shows significant seasonal variation (3.2–4.5 km2) due to evaporation in the summer months, with an average value of 3.7 km2.

References

  1. 1 2 3 4 5 6 "Eastern Africa: Northern Tanzania, on the border with Kenya". World Wildlife Fund.
  2. 1 2 "Lake Natron Basin". Ramsar Sites Information Service. Retrieved 25 April 2018.
  3. published, Marc Lallanilla (2 October 2013). "Lake That Turns Animals to Stone? Not Quite". livescience.com. Retrieved 16 June 2024.
  4. "Alkaline Environments", authored by W. D. Grant and B. E. Jones, in Encyclopedia of Microbiology, editor-in-chief Joshua S. Lederberg, Academic Press, 2010, page 129, accessed 24 November 2014
  5. Joseph Stromberg (2 October 2013). "This Alkaline African Lake Turns Animals into Stone". Smithsonian Magazine. Retrieved 11 May 2023.
  6. Swancer, Brent (20 April 2015). "The Bizarre Medusa Lake of Africa" . Retrieved 1 June 2019.
  7. Billock, Jennifer (14 June 2016). "The Deadly Lake Where 75 Percent of the World's Lesser Flamingoes Are Born". Smithsonian . Retrieved 17 June 2016.
  8. "Position Statement on the Lake Natron Project" (PDF). Tata Chemicals. 13 June 2008. Archived from the original (PDF) on 5 October 2013. Retrieved 7 October 2013.
  9. Shoo, Rehema Abeli (2020), "Ecotourism Potential and Challenges at Lake Natron Ramsar Site, Tanzania", Protected Areas in Northern Tanzania, Geotechnologies and the Environment, vol. 22, Springer International Publishing, pp. 75–90, doi:10.1007/978-3-030-43302-4_6, ISBN   978-3-030-43301-7