Rusting Waters: Alaskan Rivers Turning Orange
Madisen Kim '27
Six years ago, if one were to travel to Kobuk Valley National Park in Northwest Alaska, they would find the clearest waters in the state. Crystalline rivers in the national park were home to millions of salmon, allowing onlookers to see the moving hues of orange and red in the bubbling streams. Now, however, visitors to Alaska’s Salmon Rivers are shocked by the muddy rivers of orange-yellow murk. The once-clear rivers have become “rusting rivers,” a phenomenon in which rivers are exposed to high levels of toxic metals, like iron and zinc.
Climate change has led to increased permafrost thawing in regions with a high elevation. Permafrost means “frozen ground” and consists of soil, sand, sediment, and rock (Sarah Kuta, 2025). Usually, permafrost protects groundwater from interacting with sulfide minerals in the bedrock. However, the rising temperatures has caused permafrost to thaw, which exposes sulfur minerals in the bedrock to water and oxygen for the first time in thousands of years. The exposure then oxidizes the sulfur, transforming it into sulfuric acid. When sulfuric acid comes into contact with rocks near bodies of water, the acid dissolves the metals in the rock, which then causes the metal to leach into the water (Warren Cornwall, 2025). Consequently, the highly acidic, iron-rich waters flow into nearby rivers, dying the water orange. To University of Alaska Anchorage ecologist, Paddy Sullivan, the rivers look like “lava that’s running through a burn scar” (Cornwall, 2025).
The influx of metal in Alaska’s once salmon-abundant rivers has damaged numerous aquatic ecosystems and led to a void of wildlife. Sullivan and his team conducted a series of experiments on the Alaskan waterways, extracting samples of the water for quality testing in 2022 and 2023. The team found metals, like aluminum, cadmium, copper, iron, nickel and zinc, “at concentrations above the U.S. Environmental Protection Agency’s safe limits for aquatic life” (Kuta, 2025). In addition, the clouded water, filled with fine metal sediment, reduces the amount of light able to permeate the river’s surface. The sediments in the river also “smother insect larvae eaten by the salmon and other fish,” and also some salmon species have faced breeding challenges, as they encounter trouble laying eggs in “gravel beds choked with fine sediment” (University of California-Riverside, 2025).
The biggest problem in trying to prevent the spread of contamination in these Salmon Rivers is that the metals leaching into these rivers have “hundreds of contamination sources” as permafrost thawing can happen anywhere where there is frozen ground (UoC- Riverside, 2025). As a result, the only way to mitigate the negative impacts of this phenomena is to try to resolve the underlying problem: climate change.
The transformation of these once crystal-clear waters has rattled communities around the world. Hopefully, these strange phenomena of rivers have brought light to the impacts of climate change–even in remote areas–where these rivers had previously not been impacted by anthropogenic sources and were considered natural wonders. Now, the modern, industrialized society has impacted the rivers in irreversible ways.
As Tim Lyons, a biogeochemist at University of California–Riverside, reflects, “There are few places left on Earth as untouched as these rivers [...] But even here, far from cities and highways, the fingerprint of global warming is unmistakable. No place is spared” (UoC-Riverside, 2025). Now, more than ever, humans need to join forces to combat climate change and preserve the natural world.
References
Cornwall, W. (2025, September 8). Thawing permafrost is turning Arctic rivers orange—spelling trouble for fish. (2025). AAAS Articles DO Group. https://doi.org/10.1126/science.z y1ev1g
Dooley, E. C. (2024, May 20). Alaska’s Rusting Waters: Pristine Rivers and Streams Turning Orange. UC Davis. https://www.ucdavis.edu/climate/news/alaskas-rusting-waters pristine-rivers-and-streams-turning-orange
University of California - Riverside. (2025, September 18). Why Alaska’s salmon streams are suddenly bleeding orange. ScienceDaily. www.sciencedaily.com/releases/2025/09/ 250918011602.htm
Kuta, S. (2025, October). Why Is This Remote and Rugged River in Alaska Turning Orange? Smithsonian Magazine. https://www.smithsonianmag.com/smart-news/why-is-this remote-and-rugged-river-in-alaska-turning-orange-180987431/