Lake Urmia is Iran’s large hypersaline lake, famous for vivid pink and red hues.
It lies between Iran’s East Azerbaijan and West Azerbaijan provinces. The lake has no natural outlet to the sea, so evaporation concentrates salts in its basin. Salt-tolerant microorganisms, including algae and archaea, can give the water reddish colours, especially when the lake becomes shallower and saltier.
Lake Urmia was once one of the largest lakes in the Middle East, but its area declined sharply from the late twentieth century because of drought, water diversion and dam construction. Restoration efforts have aimed to return more water to the lake and protect its wetland ecosystem.
Despite its colour and extreme salinity, Lake Urmia does not support fish populations. Brine shrimp and specialised microorganisms are better adapted to its conditions.