Did You Know?
Dunaliella salina is not the only organism that produces pink hues in water bodies. In various parts of the world, high concentration of phytoplankton, which are microscopic plant-like organisms, also turn the water into a bright red color during the day and a bioluminescent blue at night.
The Lake Retba is situated in Northwest Africa, in Cap-Vert Peninsula that lies 30 km northeast of the capital, Dakar. The lake, which is also well-known by its French name Lac Rose, is known for its naturally occurring pink waters. The water in the lake is extremely saline, thus giving it its buoyant property. The lake is separated from the Atlantic Ocean, only by a narrow strip of dunes, and is being considered to be named as a World Heritage Site. The pink color of the lake is especially visible during the dry season (November - June) and lessens during the rains (July - October).
Why is it Pink?
The water of the lake has a pinkish hue to it. And no, it is not because of some chemical reaction. The reason for the unique pink color of the water is, in fact, an algae called Dunaliella salina, which gets attracted to the lake because of its high salinity. This particular bacteria produces a red pigment, so as to absorb sunlight, which gives the lake its distinct pink color. Hardly any other microorganisms are able to survive in the lake because of its high salt content. However, Dunaliella salina has the ability to produce enormous amounts of beta-Carotene, the reason why this single-celled organism is able to survive. The beta-Carotene helps the algae to protect itself against the intense sunlight that is reflected off the salt, and also gives it the dark pink hue. During summer, the saline level of the waters is very high. Due to this, not only does the water turn strawberry pink, it also becomes bloody red at times.
Can You Swim in it?
The color of the lake might make one wonder whether or not the water is clean and safe. It might amaze you that not only is the water fit for swimming, it is also fit for consumption. Additionally, the algae too is very rich in antioxidants, the reason why it is often used in cosmetics as well as dietary supplements. There are even a few species of fish that survive in the saline water due to their ability to pump out extra salt, keeping their water levels balanced.
Needless to say, the lake is also well-known for its salt production. One can always see salt collectors at work near the lake. The shores are full of salt piles, making it a wonderful landscape of white and pink when seen from afar. This salt is collected by the locals merely by using their hands. It is then placed into baskets and carried to the shore. The salt is washed and dried in the sun, after which it forms a dense shell that is further crushed. This salt is then sold and used by the locals, mainly for fish preservation.
Workers spend up to 12 hours each day collecting salt from the lake bed. To protect themselves from the salinity of the water, they put "Beurre de Karité" on their skin, which is shea butter obtained from the shea nuts.