
Southern half of Lake Natron. In the inset, numerous, near-white salt-crust "rafts" pepper the shallowest parts of the lake. In the top image,
fault scarps and the
Gelai Volcano can also be seen.
'Lake Natron' is a
saline lake located in northern
Tanzania, close to the
Kenyan border, in
Africa's
Great Rift Valley. The lake is quite shallow, less than three meters (10 feet) deep, and varies in width depending on its water level.
The color of the lake is characteristic of those where very high
evaporation occurs. As water evaporates during the dry season, salinity levels increase to the point that salt-loving
microorganisms begin to thrive. Salt-loving organisms include some
cyanobacteria, tiny bacteria that grow in water and make their own food with
photosynthesis as plants do. The red pigment in the cyanobacteria produce the deep reds of the open water of the lake, and orange colors of the shallow parts of the lake.
The
alkali salt crust on the surface of the lake is often colored red or pink by the salt-loving
microorganisms that live there. And the lake is the only breeding area for the 2.5 million endangered
Lesser Flamingoes that live in the valley, the most import. As salinity increases, so do the number of cyanobacteria, and the lake can support more nests. These flamingoes flock along saline lak es in the region, where they feed on
Spirulina (a blue-green algae with red pigments). Lake Natron is the only breeding location for Lesser Flamingoes because its
caustic environment is a barrier against predators trying to reach their nests. The temperatures in the mud can reach 50 degrees Celsius (120 degrees Fahrenheit), and depending on rainfall, the alkalinity can reach a
pH of 9 to 10.5 (almost as alkaline as straight
ammonia). Even more amazing than the ability of the flamingoes to live in these conditions is the fact that an endemic species of fish, the alkaline
tilapia (''
Oreochromis alcalica''), thrives in the waters at the edges of the hot spring inlets.
Threats to the salinity balance from increased fresh water influxes will come from projected
logging in Natron watersheds and a planned
hydroelectric power plant. Although development plans include construction of a dike at the north end of the lake to contain the fresh water, the threat of dilution to this breeding ground may still be serious.
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 deleveopment will leave lesser flamingoes in East Africa facing extinction'.
Because of its unique biodiversity, Tanzania named the Lake Natron Basin to the
Ramsar List of Wetlands of International Importance on July 4, 2001.
See also
★
Rift Valley lakes
Currently a group of 20 East African conservation and environmental institutions are running a world wide 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, Head of Ecology at African Conservation Centre. Ken says "This is one development that must be opposed by all means. Environmental conservation is more important than corporate profits and community livelihoods more precious than token jobs"
To sign the petition, one can log in using logging at www.tempoweb.com/yfc
References
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Lake Natron, Tanzania
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Lake Natron, Tanzania
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External links
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LakeNet Profile