A new study has revealed that rivers and lakes in Alaska are undergoing a change in color, shifting from clear blue to murky green. This transformation is caused by the release of organic sediments during intense glacial melting. Researchers from various institutions, including the National Park Service and the California Institute of Technology, have conducted studies in 75 locations along the Brooks Range in Alaska, drawing attention to this issue. The study, published in the journal Communications: Earth & Environment, indicates that over the past fifteen years, rivers and lakes in these areas have become murky and green. Scientists have identified specific sediments, such as clay, silt, organic matter, nitrogen, and phosphorus, as the main contributors to this discoloration. These sediments predominantly originate from glacial ecosystems as the melting glaciers carry and deposit ancient sediments that have been trapped within them for thousands of years.

One of the study’s co-authors, Brett Poulin, an environmental scientist from UC Davis, highlighted that similar phenomena have been observed in other regions affected by historical mining activities, such as certain areas of California and parts of the Appalachian Mountains. In these places, human influence has caused natural processes to occur in the rivers. However, Poulin also emphasized the shocking nature of witnessing these changes in the pristine and remote environment of Alaska, far away from human activity.