VIOLET, magenta, scarlet, emerald鈥� an algal bloom revives the 鈥淒ead Sea鈥� in northern China into an artist鈥檚 palette.
Usually found in oceans, this algal species, Dunaliella salina, is made up of the most salt-tolerant complex, or eukaryotic, cells ever discovered. The cells usually appear green, but intense environmental stresses trigger them to produce colourful pigments called carotenoids.
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In Yuncheng Salt Lake in Shanxi, northern China, D. salina is exposed to intense light and heat every summer. Combined with the lake鈥檚 high salinity, this supercharges its metabolism, causing it to produce large amounts of harmful, oxidising free radicals as byproducts. Carotenoids are powerful antioxidants, so making them in parallel helps spare the cells from damage.
The lake has been in full colour since June, becoming a major tourist spectacle. But all is not well beneath the surface. As the bloom spreads, it deprives the lake of oxygen and nutrients, endangering the lives of the lake鈥檚 other inhabitants.
D. salina has previously put on similar displays in other salt lakes elsewhere, including in Turkey, Iran and Australia. It is exploited commercially around the world to produce colourings for foods and cosmetics.
Photograph
TopPhoto/Alamy Live News
This article appeared in print under the headline 鈥淩ainbow lake鈥�
