Rock weathering and nutrient cycling along an erodosequence

Rock weathering and nutrient cycling are fundamentally controlled by regolith residence time, not landscape erosion rates. This study, conducted across three global mountain sites—Swiss Central Alps, Southern Sierra Nevada, USA, and the slowly-eroding tropical Highlands of Sri Lanka—reveals that weathering is supply-limited in Sri Lanka, where it runs to completion, while kinetically-limited in faster-eroding regions like the Alps and Sierra Nevada. These differences shape ecosystem processes, with nutrient recycling being more intense in supply-limited settings. The research used extensive geochemical and isotopic data, combined with regolith production rates from cosmogenic nuclides and river loads, to derive elemental fluxes through regolith and vegetation. Notably, weathering rates are independent of biomass growth, and a deficit in river solute export suggests alternative pathways for element loss, such as plant uptake or rare flushing events.

von Blanckenburg, F., Schuessler, J. A., Bouchez, J., Frings, P. J., Uhlig, D., Oelze, M., Frick, D. A., Hewawasam, T., Dixon, J., & Norton, K. (2021). Rock weathering and nutrient cycling along an erodosequence. American Journal of Science, 321(8), 1111–1163. https://doi.org/10.2475/08.2021.01