Portuguese 
English 
Spanish 
5 min of reading 
0 comments 
Lake Hillier, on Australia’s west coast, was one of the world’s most photographed natural phenomena due to its vibrant bubblegum pink color. But since 2022, extreme rainfall attributed to climate change has diluted the water’s salinity and disrupted the microbial community that produced the pigment. The lake has taken on a grayish-blue hue, and authorities warn that recovery could take up to 10 years. Scientists are now studying the environment as an analogue for Mars.
Lake Hillier was for decades Australia’s most improbable postcard: an electric pink stain in the middle of an uninhabited island, surrounded by green vegetation and the blue of the Indian Ocean. Located on Middle Island, part of the Recherche Archipelago on the south coast of Western Australia, the lake, only 600 meters long, attracted tourists from all over the world who paid for scenic flights just to see its bubblegum-colored waters from above. But climate change did what seemed impossible: it erased the color that made the lake famous.
Since 2022, visitors are advised not to expect the intense pink that went viral on social media. Atypical extreme rainfall hit Western Australia and significantly diluted the water’s salinity, reducing the osmotic stress that forced the lake’s microorganisms to produce the pigments responsible for the coloration. The result was immediate and dramatic: Lake Hillier went from electric pink to grayish-blue, more like any other common salt lake. The Australian press documented the transformation between 2022 and 2025, and in 2026 the historic color has still not returned.
The science behind the pink color that fooled the world for decades
According to information released by the NSC portal, for a long time, the explanation for Lake Hillier’s pink color was attributed to a single microalga called Dunaliella salina, which produces reddish carotenoids as protection against solar radiation and excess salt. But a study published in 2022 in the journal Environmental Microbiome turned this explanation on its head. The research, led by scientist Maria A. Sierra from Weill Cornell Medicine, performed a complete metagenomic analysis of the lake’s water.
-
Dentist explains why some people hardly brush their teeth and have no cavities, while others suffer even with good hygiene: genetics, saliva pH, acidic mouth, tartar, and sensitivity help to understand the differences and risks to oral health.
-
Madrid received more than 9 million visitors in the last year and establishes itself as one of the most desired destinations in Europe, combining history, cuisine, and landmarks such as Plaza Mayor, Parque del Retiro, and the Temple of Debod to attract tourists from around the world.
-
Twenty-two giant blocks of the legendary Pharos of Alexandria have been recovered from the seabed, and the discovery is rewriting what was known about one of the seven wonders of the ancient world.
-
The highest railway in the world climbs to 5,072 meters in Tibet — the carriages have a pressurized oxygen system because there isn’t enough air up there for passengers to breathe.
The discovery was surprising: Dunaliella salina represents only 0.1% of the lake’s microbial DNA. The main organism responsible for the pink coloration is a bacterium called Salinibacter ruber, which produces red pigments called bacterioruberins. Other species such as Halobacillus, Psychroflexus, and Halorubrum also contribute pigments. At least two of the 21 species whose complete genome was identified were previously unknown to science. What appeared to be the work of a single alga is, in fact, the result of a complex microbial community with dozens of species working together.
How extreme rainfall erased the lake’s color in a matter of weeks
In 2022, Western Australia was hit by atypical extreme rainfall attributed in part to global climate change. The volume of precipitation diluted the water of Lake Hillier and reduced the extreme salinity that sustains specialized microbial life. Without the salinity that normally exceeds ten times that of the ocean, the microorganisms did not disappear, but drastically reduced the production of the pigments that give the pink color.
The logic is biochemical: carotenoids and bacterioruberins are produced in response to osmotic stress caused by excess salt. When salinity drops, microorganisms no longer need to protect themselves and stop producing the pigments, just as an umbrella is closed when the rain stops. The difference is that rebuilding the original salinity and restoring the microbial community to its previous balance could take up to a decade, according to Australian national park authorities.
Lake Hillier as a Living Laboratory and Analog of Mars
The extreme environment of Lake Hillier has always intrigued science, but the discovery of the complexity of its microbial community has elevated interest to another level. The lake functions as a living laboratory of microbiology, hosting polyextremophilic organisms capable of surviving multiple extreme conditions simultaneously: salinity dozens of times higher than that of the ocean, intense ultraviolet radiation, and sharp temperature variations.
These conditions are similar to what scientists expect to find in some environments on Mars, making Lake Hillier a terrestrial analog for astrobiology research. If microorganisms can thrive in the hypersaline waters of Australia, it is plausible that similar life forms could exist in Martian saline deposits. The temporary loss of pink color did not eliminate the scientific value of the lake: on the contrary, it offered researchers the rare opportunity to study how a microbial community reacts and reorganizes after environmental disturbance.
The Other Pink Lakes of the World and the Pattern that Concerns Scientists
Lake Hillier is not the only pink body of water on the planet, but it is the most famous. There are dozens of lakes with similar coloration around the world, all sharing the same profile: high salinity, relative isolation, and specialized microbial community. Lake Retba in Senegal has faced nitrate issues that threaten its ecosystem. Pink Lake, also in Esperance, Australia, lost its color over 20 years ago and has never recovered.
The pattern is concerning because it shows that the pink color of these lakes is more fragile than it seems. Any change in salinity caused by atypical rains, pollution, or changes in sea level can disrupt the microbial community, and recovery is not guaranteed. For Lake Hillier, the official expectation is up to ten years, but the example of Pink Lake demonstrates that the return of the color may simply not happen if climatic conditions do not return to the previous pattern.
What the Loss of Pink Color Teaches About Climate Change
The story of Lake Hillier has become a concrete example of how even landscapes considered stable can be transformed by seemingly small changes in climate. The lake did not dry up, was not polluted by direct human action, and did not lose its microbial fauna, but it lost the characteristic that made it unique and that supported a tourism industry of scenic flights and photographic tours.
For scientists, the case illustrates that the impacts of climate change are not always catastrophic in the traditional sense, but can be profound in unexpected ways. A lake that loses its color does not generate climate refugees nor destroy crops, but eliminates a natural and scientific heritage that took millennia to form and that, once lost, may not return within a human lifetime.
Did you know that the world’s most famous pink lake lost its color due to climate change, or did you think the landscape was permanent? Tell us in the comments if you have ever dreamed of visiting Lake Hillier and what you think about natural phenomena that disappear before we can see them.
Be the first to react!