Lake Natron is a saline lake located in northern Tanzania, in the eastern branch of the East African Rift. The lake is fed by the Ewaso Ng’iro River and also by mineral-rich hot springs. It is quite shallow, less than three metres (9.8 ft) deep, and varies in width depending on its water level, which changes due to high levels of evaporation, leaving behind a mixture of salts and minerals called Natron. The English word natron is derived from the Ancient Egyptian word n?ry ‘natron’. The modern chemical symbol for Sodium, Na, which refers to Wadi El Natrun or natron valley in Egypt from which natron was mined in ancient Egypt for use in burial rites.
The lake is the only regular breeding area in East Africa for the 2.5 million Lesser Flamingoes, whose status of “near threatened” is a consequence of their dependence on the single breeding location. As salinity increases, so do the number of cyanobacteria, and the lake can support more nests. These flamingoes, the single large flock in East Africa, gather along saline lakes in the region, where they 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 Flamingo also breeds on the mud flats.
The most interesting thing than the ability of the flamingoes to live in these conditions is the fact that two endemic fish species, the alkaline tilapias (Alcolapia latilabris and A. ndalalani). A. alcalica is also present in the lake, but not endemic, thrive in the waters at the edges of the hot spring inlets.
Because of its unique biodiversity, Tanzania named the Lake Natron Basin to the Ramsar List of Wetlands of International Importance . The lake is also the World Wildlife Fund East African halophytics ecoregion.