Permafrost thaw controls iron flux from wetlands and sulfide-bearing rocks to Arctic rivers and streams

Communications Earth & Environment
By: , and 

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Abstract

Recent warming has caused widespread iron mobilization into Arctic waterbodies that degrades ecosystems and threatens natural resources. Yet, understanding where and when iron flux occurs remains limited. Here, we investigate iron loading across regional to local scales in Arctic Alaska using climate, water chemistry, and borehole data together with mapped geology and permafrost presence. We show that both anoxic microbial iron reduction and acid rock drainage from iron-sulfide oxidation mobilize iron. Iron influx is strongly associated with lowland wetlands, sulfide-rich upland bedrock, and near-surface permafrost. Acid rock drainage chemistry correlates very strongly with the depth of seasonal thaw above permafrost from the previous year, indicating a one-year lag. These findings clarify the spatial and temporal dynamics of Arctic river rusting, provide a mechanistic understanding of the phenomenon, and may allow anticipation of its occurrence and assessment of its implications for aquatic ecosystem health and subsistence resources under ongoing climate change.

Suggested Citation

Dial, R.J., Hanna, C., Sullivan, P.F., Cooper, D., Tino, C., Gregory, D.D., Diamond, C., Rieser, M., Nicolsky, D., Hill, K., Iwahana, G., Koch, J.C., Carey, M.P., Miller, L., and Lyons, T., 2026, Permafrost thaw controls iron flux from wetlands and sulfide-bearing rocks to Arctic rivers and streams: Communications Earth & Environment, v. 7, 465, 19 P., https://doi.org/10.1038/s43247-026-03450-x.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Permafrost thaw controls iron flux from wetlands and sulfide-bearing rocks to Arctic rivers and streams
Series title Communications Earth & Environment
DOI 10.1038/s43247-026-03450-x
Volume 7
Publication Date April 06, 2026
Year Published 2026
Language English
Publisher Nature
Contributing office(s) Alaska Science Center Water
Description 465, 19 P.
Country United States
State Alaska
Additional publication details