Written by 6:57 am Science & Technology Views: [tptn_views]

Alaska’s Arctic Waterways Are Turning a Foreboding Orange

Dozens of once crystal-clear streams and rivers in Arctic Alaska at the moment are shiny orange and cloudy, and in some cases becoming more acidic. This otherwise undeveloped landscape now looks like an industrial mine has been in operation for many years, and scientists need to know why.

Roman Dial, a professor of biology and arithmetic at Alaska Pacific University, first noticed marked changes in water quality during field work within the Brooks Range in 2020. He spent a month with a team of six graduates they usually couldn’t find suitable water to drink. “There are so many streams that aren’t only stained, but are so acidic that they curdle your milk powder,” he said. In others, the water was clear, “but you could not drink it since it had a very weird mineral taste and aftertaste.”

Dial, who has spent the last 40 years exploring the Arctic, has been collecting data on climate change within the Alaskan tree line for a project that also includes the work of ecologists Patrick Sullivan, director of the Environment and Natural Resources Institute on the University of Alaska Anchorage, and Becky Hewitt, a professor in environmental science at Amherst College. Now the team delves into the mystery of water quality. “I feel like I’m a graduate student in a lab I do know nothing about and I’m fascinated by it,” said Dial.

Most of the rusting waterways are in Alaska’s most distant protected areas: Arctic National Wildlife Refuge, Gates of the Arctic National Park and Preserve, Kobuk Valley National Park, and Selawik Wildlife Refuge.

The phenomenon is visually striking. “It looks like something has been broken off or something has been exposed in a way that has never been exposed before,” Dial said. “All the hard rock geologists who have a look at these photos think, ‘Oh, this looks like acid mine tailings.’ But it is not mine waste. According to scientists, the rusty coating on rocks and stream banks comes from the land itself.

The dominant hypothesis is that climate warming is causing the degradation of the permafrost. This releases iron-rich deposits, and when these deposits get into running water and open air, they oxidize and tackle a deep rusty orange color. Oxidation of minerals within the soil may also make water more acidic. The research team continues to be within the early stages of identifying the cause to raised understand the results. “I feel the pH issue” – the acidity of the water – “is absolutely concerning,” Hewitt said. While pH regulates many biotic and chemical processes in streams and rivers, the precise effect on the intricate food webs that exist in these waterways is unknown. From fish to stream bugs and plant communities, the research team is not sure what changes might result.

The rusting of Alaska’s rivers is more likely to affect human communities as well. Rivers akin to the Kobuk and Wulik, where rusting has been observed, also function sources of drinking water for a lot of communities, mostly Alaska Native, in Northwest Alaska. One of the key concerns, Sullivan said, is how water quality, if it continues to deteriorate, could affect the species that function a significant food source for Alaska’s Native individuals who live a subsistence lifestyle.

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