Arctic River Rusting Driven by Iron Release from Permafrost Thaw

Nature Communications, 6 April 2026

Arctic warming increases the amount of iron draining out of permafrost ground and entering rivers and streams, with important implications for aquatic ecosystems and subsistence resources. This study shows that permafrost thaw causes iron release through two main pathways: microbial activity in waterlogged environments and chemical reactions from sulfide-rich bedrock. Iron release most commonly occurs in areas with lowland wetlands, sulfide-rich bedrock, and near-surface permafrost. Iron drainage from bedrock is closely linked with how deeply the ground thawed the year before, showing a one-year delay. Together, these findings help identify where and when the eye-catching orange “rusting” of Arctic rivers is likely to occur as iron and other metals enter waterways under ongoing warming.

Paper | Coverage on Arctic Rivers by NRDC