Alaskan rivers turning orange due to climate change, study finds | Alaska

Dozens of Alaska’s rivers and streams are turning a rusty orange color, likely due to a new phenomenon caused by thawing permafrost. study find.

The North Pole is fastestAs the frozen ground below the earth’s surface thaws in the warmest regions of the world, minerals once locked up in the soil are beginning to seep into waterways.

“What we’re seeing in some of our nation’s most pristine rivers is the unanticipated effects of climate change,” said study author Brett Poulin, assistant professor of environmental toxicology at the University of California, Davis. he said.

Thawing permafrost causes weathering in which minerals are exposed to oxygen, which increases water acidity and dissolves metals such as zinc, copper, cadmium and iron. Iron is the most visible metal that gives rivers their rusty color and can be seen in satellite images. The study highlights potential degradation of Arctic drinking water and risks to fisheries.

“Mixing with another river can actually make the metal even stronger.” [in its] “The health implications for aquatic life are enormous,” Poulin said.

The phenomenon was first observed in 2018, when researchers noticed that rivers across the Brooks Range in northern Alaska appeared milky-orange, a stark contrast to the crystal-clear water seen the previous year.

Within that year, two local fish species, the dolly varden and the slimy deer, had completely disappeared from the tributaries of the Akilik River in Kobak Gorge National Park.

“Our data suggests that when rivers turned orange, there was a significant reduction in macroinvertebrates and biofilm on the riverbed, which is essentially the base of the food web,” Poulin said. He talked about the rust phenomenon. “It could change where the fish can live.”

Rust is a seasonal phenomenon, typically occurring in the summer months from July to August when the soil is at its deepest thaw. Researchers from the National Park Service, U.S. Geological Survey, and the University of California, Davis are currently investigating the long-term effects of changes in water chemistry in places with persistent permafrost, including Arctic regions and parts of Alaska, Canada, and Russia. I would like to understand more deeply. Scandinavian.

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“This region is warming at least two to three times faster than the rest of the planet,” said Scott Zolkos, an Arctic scientist at the Woodwell Climate Research Center who was not involved in the study. “I’m here,” he says. “So we can expect these kinds of impacts to continue.”

The research group announced that it is working closely with Alaska’s tribal liaisons to ensure local communities have accurate information about the evolution of this phenomenon.