Tracing nutrient uplift from permafrost thaw using radiogenic Sr isotopes in plants: A field-based soil warming experiment
(2026) Applied Geochemistry — Vol. 206, p. 106914 (2026)
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- Authors
Roux, Philippe 
- Abstract
- Permafrost thaw in Arctic ecosystems is altering soil structure and hydrology, deepening the active layer and increasing the availability of nutrients previously locked in frozen ground. These changes contribute to the current trend of increased plant productivity and shifts in species composition. Because arctic plant functional types have specific nutrient acquisition strategies due to differing rooting depths, it is therefore essential to identify the mechanisms responsible for changes in nutrient sources during permafrost degradation. The aim of this study is to quantify the contribution of biological cycling and/or water table rise to nutrient sources available to four major plants upon permafrost thaw. To do so, we developed a mass balance model based on an eight-year soil warming experiment on the Eight Mile Lake study site in Interior Alaska. This model combines vegetation composition survey, water table depth data with foliar strontium (Sr) concentrations and isotopic composition (87 Sr/ 86 Sr) to simulate Sr transfer in the soil-plant system. Our results show that biocycling alone is sufficient to explain the isotopic shift under control conditions for all four plants. Under soil warming, however, biocycling accounts for 37-54% of the observed shift for shallow and intermediate rooted species, while water table rise accounts for 35-47%. Although all modelled values remain within the range of observed variability, 2-20% of the observed shift remains unresolved across species. While permafrost thaw is a key source of newly available nutrients, our model suggests that redistribution mechanisms are the primary drivers of changes in plant nutrient sources.
- Affiliations
Citations
Roux, P., Lemarchand, D., Schuur, E., & Opfergelt, S. (2026). Tracing nutrient uplift from permafrost thaw using radiogenic Sr isotopes in plants: A field-based soil warming experiment. Applied Geochemistry, 206, 106914. https://doi.org/10.1016/j.apgeochem.2026.106914 (Original work published 2026)