Alaskan rivers are turning orange! Here's why
A recent study published in the journal Communications: Earth and Environment, has revealed a significant color shift in Alaska's rivers and streams, from their natural blue to a rusty orange. This unexpected transformation is linked to the release of toxic metals by thawing permafrost, an unforeseen consequence of climate change. The research, conducted by the National Park Service, the University of California at Davis, and the US Geological Survey, involved tests at 75 locations across Alaska's Brooks Range waterways.
Toxic metals released from thawing permafrost
The discoloration of Alaskan waterways is due to the release of metals such as iron, zinc, copper, nickel, and lead. As permafrost thaws, it exposes waterways to minerals buried underground for thousands of years. Brett Poulin, a co-author of the study and professor at UC Davis, noted that such occurrences are familiar in regions with mining history, like parts of California and Appalachia. However, he was surprised to witness this occurrence in remote wilderness areas far from mining sources.
Arctic warming accelerates permafrost thawing
Arctic soils naturally contain organic carbon, nutrients, and metals like mercury within their permafrost. Rising temperatures have caused these minerals and surrounding water sources to interact as the permafrost melts. Poulin suggested that the accelerated thawing of soil in that area is likely responsible for what they are observing. The Arctic is warming four times faster than the rest of the world, according to multiple studies.
Satellite imagery tracks river discoloration timeline
Researchers used satellite imagery to determine when the color change occurred in different rivers and streams. Poulin pointed out that at several locations where it occurred, the most significant increases took place between 2017 and 2018, aligning with the warmest years recorded up to that point. This discoloration has been linked to significant declines in aquatic life, raising concerns about how continued permafrost melting will affect communities that rely on these waterways for drinking water and fishing.
Global impact of climate change on mountain water sources
Alaska is not the only region experiencing these effects; similar changes have been observed in Colorado's Rocky Mountains due to climate change among other factors. Research has also been conducted beyond US borders on increases in metal concentrations in mountain rivers and streams in places like the Chilean Andes, European Alps, and northern Spain's Pyrenees. These findings raise questions about how climate change will continue impacting mountain water sources globally.
