A lake in the heart of Melbourne Australia naturally turned bright pink, however it will turn back to its normal color soon. The saltwater lake became 10x saltier causing only certain organisms to be able to live there, these organisms love the salt and release a pigment that turns the lake pink annually. As Dr. Norman said when the weather is dry and warm water evaporates from the saltwater lake causing the salinity to increase eight or 10 times that of the ocean. This creates 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. Even though the lake is due to turn back to its original color when the weather cools down, I think is pretty fascinating it all naturally turned bright pink.
https://www.nytimes.com/2017/03/10/science/pink-lake-westgate-melbourne-australia.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science®ion=rank&module=package&version=highlights&contentPlacement=2&pgtype=sectionfront&_r=0
https://www.nytimes.com/2017/03/10/science/pink-lake-westgate-melbourne-australia.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science®ion=rank&module=package&version=highlights&contentPlacement=2&pgtype=sectionfront&_r=0