Experimental evidence that organo-mineral interactions regulate dissolved organic matter composition and lability across permafrost landscapes of northwestern Canada

Research demonstrates that organo-mineral interactions significantly regulate the composition and bioavailability of dissolved organic matter (DOM) in permafrost-affected freshwater ecosystems. These interactions, driven by sediment characteristics such as aluminum and iron content, can decrease DOC concentrations while increasing DOM lability, thereby enhancing biodegradation rates. The study, conducted using batch sorption experiments on six permafrost sediment types from northwestern Canada, found that yedoma sediments released substantially more water-extractable DOC than other regions. Preferential sorption of larger, humic-like compounds and displacement of mineral-bound small molecules enriched the DOM pool in labile compounds, verified through bio-incubations. This process varies with sediment characteristics reflective of landscape history, highlighting its potential impact on northern food webs and global carbon balances.

Hatten, G. K. F., Kokelj, S. V., Opfergelt, S., Froese, D. G., Alvarez, A., Young, J. M., & Tank, S. E. (2026). Experimental evidence that organo-mineral interactions regulate dissolved organic matter composition and lability across permafrost landscapes of northwestern Canada. https://doi.org/10.5194/egusphere-2026-1844