Just 21km northeast of Dakar, Senegal, lies an oddly colored lake pinched off from the Atlantic Ocean. Lake Retba (also known as Lac Rose) is only about 1.1 sq. mi. big and is separated from the Atlantic Ocean by a couple of sand dunes. What makes it stand out is its odd color.
The first time you see it you will be assailed by a flood of pink, the lake’s vivid and outstanding color, the product of micro-algae that thrives in the highly saline lake.
The lake’s average salinity is about 40% (400g of dissolved salts in 1 liter), making more than 10 times more saline than most oceans, whose salinity is on average 3.5% (35g/1 liter). During the dry season, higher evaporation rates result in salinity much higher than the Dead Sea’s.
This environment is only conducive for very few organisms, including Dunaliella salina, the micro-algae whose metabolites “dye” the lake. The algae produces beta-carotenes that is required in different physiological functions relating to adapting to the high salinity concentrations and temperatures. The beta-carotenes are also used in synthesizing food. It is these beta-carotenes (and in some cases alpha-carotenes too) that reflect the reddish-pink color when struck by sunlight, causing the lake to appear pink to the eye.
The lake is on course to becoming a World Heritage Site, and was used as the finish point for the Dakar Rally back when it was being hosted in Africa.
More than just being a pretty site, the lake has economic potential; the carotenes extracted from D. salina have numerous applications relating to human health, from making sunscreen lotions to vitamin supplements. The lake is currently being used to mine salt on a minor scale, and given that the algae is consumable, salt derived from this lake comes with a healthy sprinkling of vital carotenes.
Lake Retba isn’t the only pink lake in the world, and the following are some of the other pink lakes scattered over the globe: Pink Hutt Lagoon, Australia, Dusty Rose Lake, Canada, Masazir Lake, Azerbaijan etc.
Given that these lakes are few and far apart, the next time you are in Senegal tell your guide this: “m’emmener à Lac Rose”, and prepare to be wowed.
By Matengo Chwanya
Edited by: Nancy Nguyen
Sources: Do Go News, Tes, Lago Rosa
Africa Global News Publication
