For the second year running, Urmia Lake in northwestern Iran has ditched its trademark green hue for a blood red color but that is not a cause for concern.
The lake, which is gradually recovering after being pushed to the brink of extinction as a result of damming and developmental projects, loses a lot of water as temperatures rise.
Because the water level in Urmia Lake is already low, losing water to evaporation exposes a sensitive species of algae known as Dunaliella salina. While they normally produce a green pigment, exposure to sunlight forces the algae to produce carotenoids, a class of pigment that appears red.
The evaporation of water also leads to an increase in the lake’s salinity, providing a hospitable environment for Halobacteriaceae, which are red-pigmented salt-loving bacteria that give the lake a more pronounced red color.
According to Hojjat Jabbari, an official at the Department of Environment’s office in West Azarbaijan Province, salt concentration in the lake is presently between 320 and 330 grams per liter.
“The lake is safe but swimmers are advised to spend less time in the water due to the high salinity,” he told ILNA.
Last summer, the lake’s red color received a lot of attention online following a report by NASA’s Earth Observatory.