The color of salt ponds range from pale green to deep coral pink, and indicate the salinity of the ponds. Microorganisms create these spectacular colors, changing their own hues in response to increasing salinity.
In low-to mid-salinity ponds, green algae proliferate and lend the water a green cast. As the salinity increases, an algae called Dunaliella out-competes other microorganisms in the pond, and the color shifts to an even lighter shade of green. In mid-salinity ponds, millions of tiny brine shrimp clarify the brine and contribute an orange cast to the water. And in mid-to high-salinity ponds, high salt concentrations actually trigger the Dunaliella to produce a red carotenoid pigment. Halophiles, such as Halobacteria and Stichococcus, also contribute red tints to the hypersaline brine.