A pond in Hawaii’s Kealia Pond National Wildlife Refuge has turned pink, possibly due to drought. Scientists believe that halobacteria, a type of archaea, may be responsible for the unusual color. Lab tests have ruled out toxic algae as the cause. The pond’s high salinity, which is currently twice that of seawater, may also be a contributing factor. The pink water is not harmful to the wildlife in the refuge, but officials are warning against entering the water or consuming fish caught in it until the source of the color is identified.