Swimming in a cool, spectacular lake on a warm summer day is a relaxing and pleasing experience, but whirling in a bright pink lake is whole other kind of thrill. Most of them are safe for humans and animals, but some only seem inviting.
Microbes, and more specifically, the single-celled organisms known as halobacteria, are responsible for the unique color of some lakes. While most other life would be unable to stand living in such a harsh, salty environment, these tiny “extremophiles” thrive in high-salinity environments, according to Mother Nature Network.
The red-pinkish color of halobacteria is produced by a pigmented protein known as bacteriorhodopsin, which is related to the rhodopsin protein that's used to sense light in the retinas of vertebrates. It is used to absorb energy from the sun. It’s like photosynthesis, but with purple-pigmented bacteriorhodopsin instead of green-pigmented chlorophyll.
Pink lakes are very salty. The salt concentration of the water hovers near saturation, reaching nearly 10 times the salinity, or salt content, of the oceans, according to Live Science. Pigments in these salt-lovers’ cells, including carotenoids like those found in carrots, give the lake and its salt crust a distinctive pink hue.