Maui's pink pond may have a different cause, researchers say

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HONOLULU (KHON) — The shocking color of a pond on Maui has gained worldwide attention and garnered multiple theories, the most prevalent of which may not, in fact, be the cause.

The phenomenon was spotted earlier this month in the Keālia Pond in the Keālia Pond National Wildlife Refuge.

Initially, it was believed algae that thrives in water with high levels of salt may be to blame.

Researchers at the University of Hawaii at Manoa now say their preliminary findings point instead to a bacteria as the cause of the shocking pink color, not algae.

“The early findings have led the experts to suggest that halophilic (thriving in salt conditions) prokaryotes, also known as archaea and bacteria, were likely the cause of the brightly colored water,” UH said in a news release.

UH researcher, Marek Kirs, said he has no knowledge of something like this happening in Hawaii before.

“According to the U.S. Fish and Wildlife Service, the sand plug between the pond and the ocean washed away during the wet season,” Kirs said. “This has not happened at least since 2018. I believe that evaporation, combined with limited freshwater input, has increased the salinity (to twice the salinity of the ocean water). It could happen in similar situations.”

Kirs and another UH researcher, Stuart Donachie, are working to identify the type of halophilic prokaryotes. The U.S. Fish and Wildlife Service is working with the State to identify the cause and a course of action to implement.

The USFWS reminds the public to stay away from the water and keep their pets away from the water. They also advise to not eat any fish from the pond.

Stephanie Stack, chief research biologist for Pacific Whale Foundation, told Nexstar’s KHON last week that the fish and birds who call the pond home do not seem to be affected by the pink water, and no large die-offs had been reported.