Could Climate Change Cause More Lakes to Turn Bright Pink?

While rosy-hued waters exist naturally around the world, a pond in Hawaii recently turned pink, and Australian scientists say the same could happen there

Pink water in a pond
Keālia Pond National Wildlife Refuge Val Matsunaga via the University of Hawai'i

Ponds with bubblegum-pink water may sound like something straight out of a dream or a fairytale, but some experts say climate change might actually lead to pinker waters across the world. In Hawaii, U.S. Fish and Wildlife Service staff at Keālia Pond National Wildlife Refuge have been monitoring unusually pink water in the park since October 30, per the refuge’s website

“I just got a report from somebody that was walking on the beach, and they called me up like, ‘There’s something weird going on over here,’” Bret Wolfe, the refuge manager, told Audrey McAvoy of the Associated Press last month.  

Wolfe initially feared the color was a sign of a toxic algal bloom, such as the type that produces red tides, per the publication. But preliminary analysis suggested the culprits were single-celled, salt-loving halobacteria.

These bacteria are responsible for turning other bodies of water pink, including the Great Salt Lake’s North Arm in Utah. This area of the lake was separated from the South Arm in the 1950s with the construction of a railroad causeway. This cut off the North Arm from any influx of freshwater, raising its salinity to an average of 26 to 30 percent—double that of the South Arm—and making it an attractive environment for pinkish-orange algae (Dunaliella salina) and violet-pinkish bacteria (Halobacterium and Halococcus)

“The North Arm is sort of the worst-case scenario of what would happen in the South Arm. There are no brine shrimp, there are no brine flies, there are no green algae, and all of the macrorealities in the North Arm are dead,” David Parrott, the assistant director of the Great Salt Lake Institute, tells Darienne DeBrule of Fox13.

“The problem is the South Arm won’t turn into the North Arm—it’ll just dry up,” he adds. “And when it dries up, really the most immediate impact all of us in Utah will feel is the dust.”

Other naturally occurring pink lakes are spread out across the world. Lake Retba in Senegal, Salinas de Torrevieja in Spain and several lakes in the south of Western Australia have all taken on a rosy hue from their resident bacteria.

While the lakes may look striking, any increase in Barbie Dreamhouse-colored waters may be a sign of warming temperatures and drier conditions driven by climate change. These two impacts could make water saltier—so, in Western Australia, scientists are expecting to see more pink lakes, says Angus Lawrie, a salt lake ecology specialist at Murdoch University, to Lauren Smith and Anthony Pancia of the Australian Broadcasting Corporation (ABC).

These high-saline waters could spell trouble for animals like migratory birds that rely on them for food—though the birds at Keālia Pond seem unharmed by the color change, per the AP. 

“The unknown is how quickly these organisms can adapt to this changing environment,” Lawrie tells the ABC. “There is a real need to do further studies on these animals, because there is not enough that we know about their ecology, which has important implications for their conservation.” 

Depending on a lake’s location and hydrology, climate change might have the opposite impact: With bouts of torrential rainfall, some lakes that are already pink might lose some of their color, environmental scientist Tilo Massenbauer tells the ABC. And, while some bodies of water may turn newly pink, climate change-fueled drought might lead others to simply dry up. 

Keālia Pond’s unusual pink water certainly seems connected to drought. As of December 19, much of Maui is under abnormally dry to severe drought conditions, per the U.S. Drought Monitor. Normally, the Waikapu Stream flows into the pond, raising water levels and reducing salinity. But that hasn’t happened for a long time, per the AP. The salinity of the Keālia Pond outlet is currently greater than 70 parts per thousand—twice that of seawater. 

“I didn’t believe that it could be that pink, but it’s like a Pepto Bismol pink,” Maui resident Travis Morrin tells Jordan Gartner of KHNL. “I have some friends who have assured me that it’s a natural phenomenon. It just never happens here on Maui.”

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