The salty red waters of the Makgadikgadi Salt Pans are an easily-recognizable landmark in Botswana, and a valuable source of industrial salts.
The pink rectangles are human-built evaporation ponds in Botswana. The pools are filled with a thin layer of saline water, which evaporates easily in the warm climate. As the water evaporates, minerals precipitate and are harvested for exportation. The red tint comes from algae that thrives in medium-to-high salinity environments.
Soda ash — sodium carbonate — is used in industry for glass, metallurgy, detergents, and chemical manufacturing, while halite — sodium chloride — is tasty for eating or handy for managing ice. The Makgadikgadi Salt Pans export minerals to other countries within southern and central Africa.
The salt pans are located in the low point of a shallow basin. In periods of wet climates, the entire basin would fill with water, while during dry climates the water would infiltrate underground. The saline aquifers are unsuitable for drinking, but are tapped for exploitation by industry.
Image credit: NASA. Read more about this salt pan, or another near the Dead Sea, on the Earth Observatory. For more beautiful space imagery, check out using near-infrared to monitor plant-health, a submarine canyon in the Bahamas, or the delicate lacework of the Florida Keys.