At the Keālia Pond National Wildlife Refuge

Why's the water pink?
This Black-crowned Night Heron is standing in pink water close to sunset. It appears to be caused by a single-celled organism called halobacteria. Halobacteria are salt-loving organisms found in high salinity water bodies. The salinity in the Keālia Pond outlet is currently greater than 70 part per thousand, or twice the salinity of seawater. It is this high salinity water in the outlet that is providing favorable conditions for the halobacteria, producing the pink color.

Best viewed at original size.