Jon Birmingham

Salt Ponds, Botswana

This photograph shows the salt ponds of one of Africa’s major producers of soda ash (sodium carbonate) and salt. Soda ash is used for in making glass, in metallurgy, in the detergent industry and in chemical manufacture. The image shows a small part of the great salt flats of central Botswana known as the Makgadikgadi Salt Pans. Currently, the soda ash and salt are mainly exported to countries in southern and central Africa. Salt water from just beneath the pan floor is evaporated to produce the soda ash and salt--a process for which the semiarid climate of Botswana is ideal. Red, salt-loving algae in the ponds indicate that the salinity of the evaporating water is medium to high.

The salt pans of Botswana--an easily recognizable visual feature for astronauts aboard the ISS--lie at the low point of a vast, shallow continental basin. The featured astronaut photograph was acquired on March 1, 2007.

NASA Image of the day archive  NASA