[Global] Over the past week, the internet has been getting excited over a hot-pink lake in the heart of Melbourne. And despite what science fiction nostalgia it may conjure up, this is not a scene from “Ghostbusters” or “The X-Files.” This is very much a real, natural phenomenon that occurs all over the planet. It’s what happens when the only thing living in a supersalty lake is a single-celled, salt-loving microbe that makes pigments called carotenoids.
“It’s the equivalent of having a desert, pink lake right in Central Park,” said Mark Norman, a conservation biologist for Parks Victoria, which manages the lake. “It’s quirky and fascinating, and I love it when natural systems do something that is so large scale that it just blows everybody away.”
The lake turned pink last week, and is expected to return to its normal color when the weather cools down and rains return for Australia’s winter, which starts in June.
Dr. Norman said that when the weather gets warm and dry, this is an annual occurrence. As water evaporates from the saltwater lake, its salinity increases to eight or 10 times that of the ocean, creating an extreme habitat where few organisms can live. In Westgate Park’s lake, the only living thing is a single-celled algae. When salt concentrations are incredibly high, it starts producing carotenoids, the pigments that give the lake its color. “The carotenoid also acts as a filter to protect their chlorophyll, almost like a pair of sunglasses that goes over the chlorophyll cells and aids in photosynthesis,” he said.
Australia’s dry landscape provides other opportunities to see pink lakes fueled by this organism, like in Murray-Sunset National Park or near Dimboola in Victoria and the Hutt Lagoon and Lake Hillier in Western Australia among others. In the rest of the world, pink or red lakes exist in Spain, Senegal, the Crimean Peninsula, Azerbaijan, Tanzania, Bolivia, Kenya, Mexico and other countries. In some cases, salts or the carotenoid pigments are harvested from the lakes and used for many purposes, including flavoring, melting ice or dyeing foods and pharmaceuticals.
According to Dr. Norman, salt lakes turn pink only when the right combination of factors exists: high salinity and the right salt and organisms. The lake at Westgate Park most likely gets sodium chloride, or sea salt, underground from the nearby bay and estuarine river. Other lakes in Australia that have, for example, gypsum salt, don’t turn pink. Sediment, salinity and other organisms can also affect a lake’s pinkness.
And a pink lake is different from pink water coming from a sink, like the stuff that spewed from some Canadian taps on Thursday. That was the result of a disinfectant called potassium permanganate that leaked into the system, not algae, salt or aliens.
In other lakes where brine shrimp live alongside the carotenoid-producing algae, the shrimp turn pink after eating the algae and its carotenoids, Dr. Norman said. The pigments stick to the shrimp’s fat and the color travels up the food chain. Such carotenoid-rich brine shrimp are important to a flamingo’s diet — remove the carotenoids, and its feathers go white. The lakes that pink flamingos eat from may not appear as pink as the one in Melbourne because the algae aren’t the only things that live there.
Spain’s Las Salinas de Torrevieja, is one of these lakes. On sunny days, the salt lake blushes — more rose than hot pink. It can host thousands of flamingos during breeding season as well as a few other plants and animals, including some orchids on occasion. And so is the Laguna Colorada, in Bolivia, which attracts Chilean flamingos, James’s flamingos and Andean flamingos, one of the rarest breeds in the world. In Eduardo Avaroa Andean Fauna National Reserve, which it is a part of, you can find pumas, foxes, llamas, reptiles and other animals. This shallow but large lake, high in the Andes Mountains, is blood red because of algae and sediments. Minerals or algae give other lakes in the reserve signature colors too, like the turquoise Laguna Verde.
For the urban experience in Australia, the best way to see Westgate Park’s pink lake is to drive a car across the bridge, catch a taxi or walk — it’s only about two and a half miles from the city center. To see the pink water in all its glory, look from above, in the middle of the day. But to watch the pink water blend into pink skies, go at sunset. Just next door is a freshwater lake, which isn’t pink but can host more than 140 species of birds.
Dr. Norman said the water is so salty that swimming wouldn’t be pleasant: Getting water in your eyes would be like squirting soy sauce into them, and when it dried, it would crystallize on your eyelids: “It’s better to look at it than to jump in it.”
Photo: The lake in Westgate Park in Melbourne, Australia, turns pink because of single-celled algae producing pigments called carotenoids. Credit Agence France-Presse — Getty Images
View original article at: A lake turned pink in Australia. It’s not the only one