Lake Natron

Lake Natron lies in northern Tanzania's Arusha region near the Kenyan border, in the Eastern Rift Valley. It occupies a closed basin: water enters through rivers, rainfall and springs, but the only major route of loss is evaporation. The hot, arid climate and seasonal rainfall cause substantial changes in lake level and exposed mudflat area. During some dry periods, much of the lake can recede, leaving isolated lagoons near river and spring inlets.

The lake's unusual chemistry is linked to regional volcanism and the rocks of its catchment. NASA Earth Observatory describes sodium- and calcium-carbonate salts produced by nearby volcanic activity and carried through faults and hot springs into the lake. In this closed basin, dissolved minerals accumulate as water evaporates. Scientific research characterizes Lake Natron as a soda lake, with strongly alkaline, saline waters and deposits including trona. Salinity and alkalinity change with water level and proximity to freshwater inflows.

Although extreme for many organisms, Lake Natron supports microorganisms adapted to high salinity and alkalinity. Haloalkaliphilic archaea can contribute pink, orange or red coloration in shallow waters and on salt crusts. Cyanobacteria and other phytoplankton support food webs that include flamingos. The lake is an important regular breeding site for the East African lesser flamingo (Phoeniconaias minor); exposed mudflats and the lake's remote, water-surrounded nesting areas can help protect nests from predators. Breeding conditions vary with hydrology, and the birds' numbers and success fluctuate.

The Lake Natron basin is internationally recognized for its wetland and biodiversity importance, including through Ramsar designation. Its ecological condition is connected to water flows across a wider catchment shared by Tanzania and Kenya. Research has examined how changes to inflows, water levels, salinity and phytoplankton may affect flamingo habitat. Conservation planning therefore considers wetland processes alongside local livelihoods and land use.