Dozens of rivers and streams in Alaska have started to exhibit a striking rusty orange color, according to recent research. This unusual phenomenon is attributed to the thawing of permafrost, a consequence of rapid climate warming in the Arctic, the fastest-warming region on Earth.
What is Permafrost?
Permafrost is a permanently frozen layer of soil, gravel, and sand found beneath the Earth’s surface, often bound together by ice. It typically exists in regions where temperatures remain at or below 0°C (32°F) for at least two consecutive years. This phenomenon is common in Arctic areas like Alaska, Siberia, and northern Canada. Permafrost can be continuous, covering large areas, or discontinuous, appearing in patches. Thawing permafrost, due to rising temperatures, can release stored greenhouse gases and lead to ground instability, impacting ecosystems and infrastructure. This is sadly a significant consequence of climate change, particularly in regions warming faster than the global average.
The Science Behind the Rusty Waters in Alaska
As the permafrost beneath Alaska’s surface begins to thaw, previously trapped minerals are released into the water. This process, known as weathering, exposes these minerals to oxygen, leading to increased water acidity and the release of metals like zinc, copper, cadmium, and most notably, iron. The iron gives the water its distinctive rusty hue, which is even visible from satellite images.
“Alaska’s rivers turning rusty orange is a clear indicator of climate change’s reach into even the most remote areas,” explains Dr. Sarah Johnson, a climate change researcher at the University of Alaska Fairbanks. The alteration in water chemistry poses a significant threat to local ecosystems, potentially degrading drinking water and harming fisheries.
Alaska’s Rivers Turn Orange: A Critical Sign of Ecological Shifts
The phenomenon was first observed in 2018 when researchers noticed a milky orange tint in rivers across northern Alaska’s Brooks Range, a stark contrast to the clear waters from previous years. A notable impact of this change was seen in a tributary of the Akillik River in Kobuk Valley National Park, where two fish species, the Dolly Varden and the slimy sculpin, disappeared completely within a year.
Another leading expert on the topic, Brett Poulin, study author and assistant professor of environmental toxicology at the University of California Davis says “Our data suggests that when the river turned orange, there was a significant decrease in macroinvertebrates and biofilm at the bottom of the stream, which forms the base of the food web”. This disruption could lead to significant changes in the habitats suitable for fish and other aquatic life.
Seasonal Phenomenon of Rusting Rivers with Long-Term Concerns
The rusting occurs seasonally, predominantly during the summer months of July and August when the thaw is deepest. Researchers from the National Park Service, US Geological Survey, and University of California, Davis, are now focusing on understanding the long-term effects of this changing water chemistry in regions with continuous permafrost, such as parts of Alaska, Canada, Russia, and Scandinavia.
Scott Zolkos, an Arctic scientist at the Woodwell Climate Research Center, who was not involved in the study, commented on the broader implications, stating, “It’s an area that’s warming at least two to three times faster than the rest of the planet. So we can expect these types of effects to continue.”
Collaboration with Local Communities to Help Climate Change
In response to these findings, the research team is working closely with tribal liaisons in Alaska to provide accurate and timely information to local communities about this developing environmental concern. The collaboration aims to ensure that those directly affected by these changes are well-informed and prepared for the potential impacts.
The dramatic color change in Alaskan rivers serves as a vivid reminder of the far-reaching effects of climate change. As the Arctic continues to warm, understanding and mitigating these impacts on local ecosystems and communities becomes increasingly crucial.
