Why Alaska’s Rivers Are Turning Orange– Unveiling the Surprising Cause

Image Credit: Polarjournal

Scientists have discovered that the rivers and streams in Alaska are undergoing a dramatic color change, shifting from clear blue to a rusty orange. This startling transformation is due to the release of toxic metals from thawing permafrost, as detailed in a recent study.

Researchers from the National Park Service, the University of California at Davis, and the US Geological Survey conducted extensive tests across 75 locations in Alaska’s Brooks Range. Over the past five to ten years, these waterways have become increasingly cloudy and orange, a phenomenon now linked to climate change.

The study, published in Communications:
Earth & Environment, found that the discoloration is caused by the release of metals such as iron, zinc, copper, nickel, and lead from the thawing permafrost. These metals, previously locked away underground for thousands of years, are now entering the waterways, posing a significant threat to the ecosystems they support.

Brett Poulin, a co-author of the study and a professor of environmental toxicology at UC Davis, remarked on the unexpected nature of these findings. “We’re used to seeing this in parts of California and Appalachia where mining has occurred. However, it’s startling to witness this in some of the most remote wilderness areas, far from any mining activities,” Poulin explained.

The Arctic region, warming four times faster than the global average, is experiencing unprecedented permafrost thaw. This rapid warming causes the soil to release its stored minerals into nearby water sources. High temperatures are accelerating the melting process, leading to increased metal concentrations in rivers and streams.

Using satellite imagery, researchers pinpointed when these changes began. Significant increases in discoloration were observed between 2017 and 2018, coinciding with record-high temperatures. This shift has been linked to sharp declines in aquatic life, raising concerns about the future of communities dependent on these water sources for drinking and fishing.

Alaska’s Arctic rivers host a variety of fish species essential for subsistence, sport, and commercial fisheries. The local communities, who rely heavily on these resources, first raised concerns about the water discoloration seven years ago. Their observations have been crucial in driving this research forward.

Alaska is not alone in facing these challenges. Similar effects have been documented in Colorado’s Rocky Mountains. A study published in Water Resources Research noted increasing metal concentrations—sulfate, zinc, and copper—in 22 of Colorado’s mountain streams over the past 30 years. The reduced streamflow and thawing frozen ground were identified as significant contributors to this rise.

This issue extends beyond the United States. Researchers have observed increased metal and rare earth element concentrations in mountain rivers and streams in the Chilean Andes, the European Alps, and the Pyrenees in northern Spain. While some of these areas have been affected by mining, the recent increases highlight the broader impacts of climate change on water sources.

Researchers in Alaska plan to continue their investigations to locate the precise sources of these metals and minerals. They aim to understand better how the continued thawing of permafrost will impact both aquatic ecosystems and human communities.

The findings underscore the unexpected and far-reaching consequences of climate change, emphasizing the urgent need for further research and environmental protection initiatives. As the global climate continues to warm, understanding and mitigating these impacts will be crucial for preserving both natural ecosystems and human livelihoods.

As reported by CNN in their recent article