Thinking outside the rocks: Subsurface water storage, topography, and land cover are key modulators of large-scale riverine dissolved silicon dynamics

Geophysical Research Letters
By: , and 

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Abstract

Riverine dissolved silicon (DSi) dynamics reflect integrated geologic, hydrologic, climatic, and ecological controls. We compiled annual DSi data for 337 rivers across four continents and trained interpretable machine-learning models to predict concentrations and yields from 28 watershed variables. Both models reproduced testing data (R2 = 0.85 for concentration and 0.96 for yield) and withheld-site validation (R2 = 0.91 and 0.93). Lithology, especially volcanic rock fraction, strongly controlled DSi while subsurface storage, topography, and land cover further shaped DSi dynamics. DSi concentrations and yields exhibited nonlinear responses to basin slope, recession-curve slope, proportion of open-water cover, and nutrient availability. Concentrations showed sharper threshold responses to hydrologic and biotic variables, whereas yields varied more gradually with climate and lithology. These results provide a framework for forecasting DSi under land cover and climate change and for embedding realistic, nonlinear processes in mechanistic models.

Suggested Citation

Bush, S.A., Johnson, K., Jankowski, K.J., Carey, J.C., Sethna, L.R., Lyon, N., and Sullivan, P.L., 2026, Thinking outside the rocks: Subsurface water storage, topography, and land cover are key modulators of large-scale riverine dissolved silicon dynamics: Geophysical Research Letters, v. 53, no. 2, e2025GL118853, 12 p., https://doi.org/10.1029/2025GL118853.

Publication type Article
Publication Subtype Journal Article
Title Thinking outside the rocks: Subsurface water storage, topography, and land cover are key modulators of large-scale riverine dissolved silicon dynamics
Series title Geophysical Research Letters
DOI 10.1029/2025GL118853
Volume 53
Issue 2
Publication Date January 28, 2026
Year Published 2026
Language English
Publisher American Geophysical Union
Contributing office(s) Upper Midwest Environmental Sciences Center
Description e2025GL118853, 12 p.
Additional publication details