Lake Natron
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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 Lesser Flamingoes that live in the valley. As salinity increases, so do the number of cyanobacteria, and the lake can support more nests. These flamingoes flock along saline lakes 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.
Because of its unique biodiversity, Tanzania named the Lake Natron Basin to the Ramsar List of Wetlands of International Importance on July 4, 2001.
[edit] See also
[edit] External links
[edit] References
- Lake Natron, Tanzania. Earth Observatory Newsroom. Retrieved on 2006-04-26.
- Lake Natron, Tanzania. Earth Observatory Newsroom. Retrieved on 2003-11-14.
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