Pink Flamingo Sauce
a salty color signal... responsible for the plumage of Flamingoes.
In low salinity ponds, green algae are predominant. In high salinity ponds, the pink microalgae Dunaliella salina shifts the color to red.
The reds and oranges and yellows you see in nature are from the carotenoids, such as β-carotene (which is protective to the halophiles in this harsh environment)