Why some of Alaska’s rivers are turning orange: CBS News

By Andrew Blackman - May 23, 2024


A small headwater tributary of the Akillik Rivver in Kobuk Valley National Park in summer 2017 and summer 2018. (NPS / JON O’DONNELL)                                                                                                                                                  

For years, dozens of rivers and streams in Alaska have turned rusty orange. Scientists suspect that the change in color was caused by thawing permafrost releasing minerals into crystal clear water, CBS News reports, citing a report published in Nature Earth and Environment.

  • Scientists sampled affected water across 75 locations in a Texas-sized area of northern Alaska’s Brooks mountain range,  Some of the locations are so remote that researchers are using helicopters to access them.
  • The study revealed elevated levels of metals such as iron, zinc, nickel, copper, and cadmium in the affected water, with iron primarily responsible for the orange hue.
  • The discoloration has led to declines in the fish population, posing risks to subsistence, sport and commercial fisheries. It also threatens rural drinking water supplies, potentially affecting taste and requiring a higher level of filtration.
  • Researchers are continuing to monitor the situation, investigating the long-term effects of climate change on permafrost and water quality. They are also exploring the potential for recovery if colder temperatures return and permafrost refreezes.