A lake in Hawaii (USA) became a spectacle on social media last week after turning bubblegum pink. However, experts say the new hue is not just a photo opportunity, but an indicator of environmental stress.
Officials at Lake Kealia National Wildlife Refuge on the island of Maui have been monitoring the pink water for the past two weeks, according to the U.S. Fish and Wildlife Service, after initial fears that the color was the result of toxic algae.
Instead, tests indicated that the source of the pink hue was likely halobacteria, a type of archaea, single-celled organisms that thrive in bodies of water with high salt levels, the service said.
The salinity in Lake Kealia is currently above 70 parts per thousand, which is twice the salinity of seawater.
Coupled with dry conditions resulting from Maui’s drought, classified as “severe” in most of the county, the lake’s salinity created the perfect conditions for halobacteria to grow.
The University of Hawaii is conducting additional tests to learn more about archaea.
“Water should not pose a threat to public health,” said Shiladitya DasSarma, professor in the department of microbiology and immunology at the University of Maryland School of Medicine.
Microorganisms would not be able to survive in the human body because the body does not have enough salt for halobacteria to survive, DasSarma said.
Still, authorities have advised visitors to avoid entering the water, not to consume fish from the lake and to ensure that their pets do not drink it.
The bright pink hue is a cause for concern in the surrounding ecosystem. The color indicates that the water’s salinity levels are too high for most fish to survive or other animals to drink, DasSarma said.
“It’s basically a flashing red sign that the ecology of this area is being severely affected,” he said.
Bodies of water often turn red before they dry out, he said, although it’s unclear whether that would be the case at Kealia Lake. Officials at the site told the Associated Press that the rain could reduce salinity and potentially change the color of the water.
Color changes like these are not uncommon in the United States, DasSarma said.
A portion of Utah’s Great Salt Lake, for example, has been pink since the 1950s, according to the Great Salt Lake Collaborative, after a portion of it was separated from the rest and developed a higher salinity.
Around the world, there are other lakes that are pink or red due to high salinity, including places like Spain, Senegal, the Crimean peninsula, and Azerbaijan.
Typically, these color changes occur in much drier places.
The most recent episode in Hawaii, which is generally wet, points to more extreme weather events resulting from climate change, DasSarma said.
“This has been seen more frequently around the world, but you wouldn’t imagine it in Hawaii — it’s not an arid part of the world,” he said.