Introduction to Lake Natron
Lake Natron is a salt or alkaline lake found in northern Ngorongoro District of the Arusha Region in Tanzania, at its border with Kenya. It is situated within the Gregory Rift, which forms the eastern arm of the East African Rift. The lake is found within the Lake Natron Basin, one of the internationally recognized wetlands on the Ramsar Site. 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.
An explanation
It is supplied mainly by the Southern Ewaso Ng’iro River originating in central Kenya and mineral-rich hot springs. The lake is very shallow, only less than three metres (9.8 ft) deep. Its width varies based on the water level. The lake is at most 57 kilometres (35 mi) long and 22 kilometres (14 mi) wide. The surrounding area receives irregular seasonal rainfall, mainly between December and May, amounting to 800 millimetres (31 in) per year. Temperatures at the lake are often above 40 °C (104 °F).
Natron, a form of sodium carbonate decahydrate, and trona, sodium sesquicarbonate dihydrate, have remained due to extreme evaporation. Alkalinity levels are often found at greater than 12 on the pH scale. Bedrock is composed of Pleistocene era trachyte lavas with high levels of sodium but only very minor calcium and magnesium content. These factors have caused the lake to be concentrated into a caustic alkaline brine.
The chemical properties of the water are known to calcify the bodies of any living thing that dies in the lake.
Flora
The color of the lake is typical of those where very high evaporation rates occur. During the dry season, water evaporation increases salinity to such an extent that salt-loving microorganisms begin to thrive. Some cyanobacteria, which are halophilic, make their own food through photosynthesis, much like plants.
The red accessory photosynthesizing pigment in the cyanobacteria produces the deep reds in the open water of the lake and the orange colors in the shallow parts. The alkali salt crust on the surface of the lake is also often colored red or pink by the halophilic microorganisms that live there. Salt marshes and freshwater wetlands around the edges of the lake support a variety of plants.
Fauna
Most animals will find the high temperature of the lake (up to 60 °C or 140 °F) and also its high and variable salt content hard to hospitable. Lake Natron still houses some endemic algae, invertebrates, and birds. Around its margins in slightly less salty waters, some fish also survive.
The lake is the only regular breeding area in East Africa for the 2.5 million lesser flamingoes, whose ‘near threatened’ status is due to their dependence on this single location. Increases in salinity also increase the cyanobacteria, so it accommodates more nests.
These flamingoes, which make up the only large flock remaining in East Africa, feed on Spirulina- a blue-green algae having red pigments-from nearby saline lakes. It has proved to provide a safe breeding place because the caustic nature of this site acts as a protective barrier from the predators seeking their nests at time-forming evaporate islands. Mud flats provide more breeding for Greater flamingoes.
The lake inspired the nature documentary The Crimson Wing: Mystery of the Flamingos by Disneynature, due to its close relationship with the lesser flamingoes as their only regular breeding area.
Two endemic fish species, Alcolapia latilabris and A. ndalalani, thrive in the waters at the edges of the hot spring inlets. A. alcalica is also found in the lake but is not endemic.
Hazards and conservation
The area around the salt lake is uninhabited, but there is some herding and seasonal cultivation. Threats to the salinity balance from increased siltation influxes could arise from projected logging in the Natron watersheds and a planned hydroelectric power plant on the Ewaso Nyiro across the border in Kenya.
Although development plans include constructing a dike at the north end of the lake to contain the freshwater, the threat of dilution to this breeding ground may still be significant. There is no formal protection.
Another potential threat to Lake Natron is the development of a soda ash plant on its shore. The facility would draw water from the lake to extract sodium carbonate, which they would convert to washing powder and export.
Also expected to be included in the complex are housing units for more than 1,000 workers, as well as a coal-fired power station. There is also a possibility that the developers may introduce a hybrid brine shrimp to enhance the efficiency of the extraction process.
According to Chris Magin, RSPB 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.
Currently, a group of over 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.
According to communication made in June 2008, Tata Chemicals shall not proceed with the Natron Project and further re-examination of this project would be based on Ramsar Wetlands plan, which is prepared currently.
Due to the unique biodiversity found in Tanzania, Lake Natron Basin was named in the Ramsar List of Wetlands of International Importance on 4 July 2001. The lake also forms part of the World Wildlife Fund East African halophytics ecoregion.
1. Why is Lake Natron often called a “Deadly Lake”?
Lake Natron is known for its highly alkaline waters, which can be lethal to most animals. The lake’s pH level can range from 9 to 10.5, making it one of the most caustic bodies of water on Earth. The high alkalinity comes from the sodium carbonate and other salts that drain into the lake from the surrounding volcanic rocks. This harsh environment can kill most living creatures, with only a few specialized species managing to survive.
Despite its inhospitable conditions, Lake Natron is home to the lesser flamingo, which thrives in the alkaline waters. The flamingos feed on the algae that grow in these waters, which can survive in conditions that would kill most other forms of life. The survival of these birds in such a harsh environment has long been a mystery, with scientists studying how they are adapted to the extreme conditions of the lake.
2. What is the Role of Lake Natron in Flamingo Breeding?
Lake Natron serves as a crucial breeding ground for the lesser flamingo. The lake’s alkaline waters make it an ideal location for the flamingos to nest, as the harsh conditions discourage predators from approaching. Flamingos build their nests on small islands in the lake, where they lay their eggs in the highly mineralized mud. This mud provides a stable foundation for the eggs, and the high levels of minerals in the water help to protect the eggs from potential threats.
However, the breeding success of the flamingos is threatened by human activities in the region. Plans for industrial development, such as the construction of a soda ash factory near the lake, have raised concerns about the potential impacts on the flamingo population. The lake’s ecosystem, and the delicate balance that allows flamingos to thrive, could be disrupted by these developments, leading to a decline in the flamingo population.
3. How Do Animals Survive in the Extreme Conditions of Lake Natron?
The extreme conditions of Lake Natron might seem inhospitable to most forms of life, but certain species have evolved to thrive in the harsh environment. The algae that grow in the lake’s waters are specially adapted to survive in high salinity and high alkalinity, providing a food source for the flamingos that live there. Other organisms, such as certain species of bacteria and brine shrimp, have also adapted to the extreme conditions.
The ability of these organisms to survive in Lake Natron lies in their unique biochemical adaptations. Some of these species have specialized enzymes and metabolic processes that allow them to tolerate the extreme levels of salt and alkali. For example, the brine shrimp that live in the lake are able to extract oxygen from the water despite the high levels of salt, which would be lethal to other aquatic life.
4. What Makes Lake Natron a Ramsar Wetland of International Importance?
In 2001, Lake Natron was designated as a Ramsar Wetland of International Importance due to its unique biodiversity and ecological significance. The lake’s ecosystem supports a wide variety of species, including the lesser flamingo, which relies on the lake’s specific conditions for breeding. The Ramsar Convention recognizes wetlands that are important for the conservation of biodiversity and the provision of ecosystem services.
The lake’s role in maintaining the regional ecosystem is critical, as it supports various species of birds, plants, and other wildlife that depend on its saline waters. Furthermore, Lake Natron provides valuable ecosystem services such as water filtration and carbon sequestration, which contribute to the overall health of the environment in the region. Its designation as a Ramsar site helps to protect these vital ecological functions.
5. What Threats Does Lake Natron Face from Human Activities?
Lake Natron faces a number of threats from human activities, particularly industrial development. One of the most significant threats to the lake’s ecosystem is the proposed construction of a soda ash factory near its shores. This factory would extract soda ash from the lake’s waters, which could disrupt the delicate balance of the ecosystem and threaten the species that rely on it, particularly the flamingos.
In addition to industrial development, Lake Natron is also at risk from climate change. Rising temperatures and changing rainfall patterns could alter the water levels and chemical composition of the lake, potentially making it even more difficult for life to thrive there. Furthermore, increasing human populations in the surrounding areas could put additional pressure on the region’s natural resources, further threatening the lake’s biodiversity.
6. Why Do Some Animals Appear “Frozen” Near Lake Natron?
The image of animals appearing “frozen” near Lake Natron has been one of the most mysterious aspects of the lake. In reality, these animals aren’t frozen, but rather are covered in a layer of mineral deposits that make them appear like statues. When animals, such as birds, approach the lake and die, they are often preserved by the minerals in the water, which cause their bodies to calcify.
This phenomenon occurs due to the high alkalinity of the water, which causes the bodies of the animals to become covered in a hard, calcified shell. Over time, the bodies become mummified, giving them an eerie, frozen appearance. This process is unique to Lake Natron and has captivated scientists and photographers alike, who have been drawn to the lake to study and document this strange occurrence.
7. How Did Lake Natron Form and Why is It So Alkaline?
Lake Natron is a soda lake that formed in the basin of an ancient volcanic region. The lake is fed by a number of streams that carry minerals and salts from the surrounding volcanic terrain. These minerals, particularly sodium carbonate, are responsible for the lake’s extreme alkalinity. The high salt content of the lake comes from the evaporation of water, which leaves behind concentrated minerals that accumulate over time.
The unique combination of volcanic geology, climate, and water chemistry creates the extreme conditions that define Lake Natron. These conditions are not only inhospitable to most animals, but also contribute to the lake’s distinct ecology. The lake’s high salinity and alkalinity make it an important habitat for specialized organisms, such as the algae that provide food for the flamingos, but they also make it a dangerous place for most life forms.
8. What Is the Role of Lake Natron in the Local Ecosystem?
Lake Natron plays a critical role in the local ecosystem by supporting a wide variety of species, including birds, invertebrates, and algae. The lake serves as an important breeding ground for the lesser flamingo, which relies on the lake’s highly alkaline waters to breed and raise its young. In addition, the algae that grow in the lake provide food for a number of species, creating a unique food web that supports the local wildlife.
The lake also contributes to the health of the surrounding environment by helping to regulate water quality and maintain local climate conditions. As a vital component of the regional ecosystem, Lake Natron helps to preserve biodiversity and provides essential ecosystem services that benefit both wildlife and humans.
9. What Are the Potential Consequences of the Soda Ash Factory Near Lake Natron?
The proposed soda ash factory near Lake Natron has raised concerns about the potential impact on the lake’s delicate ecosystem. If the factory goes ahead, it could alter the chemical composition of the lake’s waters, making it less suitable for the organisms that currently thrive there. The extraction of soda ash could disrupt the food chain, affecting the algae that flamingos rely on for food.
Additionally, the industrial development could lead to habitat destruction, as the construction of the factory may encroach on the areas where flamingos breed. This could result in a decline in the flamingo population, which would have broader implications for the local ecosystem. The introduction of pollution and the alteration of the lake’s natural chemistry could also harm other wildlife species that depend on Lake Natron.
10. How Can Conservation Efforts Protect Lake Natron and Its Ecosystem?
Conservation efforts are crucial to protecting Lake Natron and the unique species that depend on it. The designation of the lake as a Ramsar Wetland of International Importance has helped raise awareness about its ecological significance. Local and international conservation groups are working to safeguard the lake from the threats posed by industrial development, including the proposed soda ash factory.
Efforts to protect Lake Natron include lobbying for the protection of the lake’s surrounding areas and promoting sustainable development practices that do not harm the ecosystem. In addition, there is a growing push for increased research and monitoring to better understand the ecological processes at play in the lake. By supporting these conservation initiatives, it is hoped that Lake Natron can be preserved for future generations, ensuring that its unique biodiversity continues to thrive.
