DAKAR, Sept. 29 (Xinhua) -- Senegal's Lake Retba, which lost its distinctive color due to flooding in 2022, has regained its signature pink hue, a phenomenon closely linked to the proliferation of salt-loving algae, researchers at Cheikh Anta Diop University of Dakar have said.
The lake, known as "Lac Rose," is a major tourist attraction in Senegal. Located north of the capital Dakar, it turns pink during certain seasons and under specific sunlight conditions due to the activity of halophilic microorganisms in its waters.
However, since late 2022, unusually heavy rainfall triggered floods that disrupted the lake's ecosystem, causing its waters to lose color and affecting local residents who rely on tourism and related commercial activities.
Cheikh Anta Diop University, in a post on Sunday on social media, said its study "concludes that the return of the lake's pink color is due to the massive reproduction of salt algae under typical dry-season conditions of high salinity and temperature."
El Hadji Sow, a researcher at the university who has long studied lake ecosystems, said changes in the lake's color are closely related to water salinity: when salinity falls, green algae dominate and the water turns green; when salinity rises, salt algae proliferate, and their red pigments transform the lake into pink or red.
With the return of Lake Retba's pink waters, local tourism and commercial activities are gradually recovering.
However, researchers have warned that the lake's ecosystem remains fragile, and some residents have expressed concern that rapid urbanization and potential water pollution in surrounding areas could affect water quality and microbial communities.
Senegal's ecological authorities have called for reducing human impacts to preserve the lake's natural cycles. ■
