Lake Hillier is a lake on Middle Island, Western Australia
Lake Hillier is a pink-coloured lake on Middle Island, the largest of the islands that make up the Recherche Archipelago off the coast of Esperance.From above the lake appears a solid bubble gum pink. The lake is about 600 meters long, and is surrounded by a rim of sand and dense woodland of paperbark and eucalyptus trees. A narrow strip of sand dunes covered by vegetation separates it from the blue Southern Ocean.
No-one fully knows why the lake is pink. Scientists speculate that the colour comes from a dye created by bacteria that lives in the salt crusts.Another hypothesis is that the pink colour is due to red halophilic bacteria in the salt crusts. Despite the unusual hue, the lake exhibits no known adverse effects upon humans.