Discharge and temperature effects on weathering fluxes in alpine and perialpine basins in Switzerland

• Published in: Journal of hydrology (Amsterdam) Vol. 610; p. 127995
• Main Authors: Rodríguez-Murillo, Juan-Carlos, Filella, Montserrat
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: Calcium; Discharge; Silicic acid; Swiss rivers; Temperature; Weathering; Swiss rivers; Weathering; Temperature; Calcium; Silicic acid; Discharge
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2022.127995

•Influence of discharge and temperature on weathering loads and fluxes in Switzerland has been studied.•Weathering loads depend mostly on discharge.•Multiple linear regression reveals the real influence of temperature, which differs from that obtained from simple regression.•The effect of temperature on weathering loads is mostly indirect, via its influence on discharge.•Runoff and lithology are the main positive factors on silicic acid fluxes, whereas temperature is the main positive factor in Cacar fluxes. Chemical weathering exerts a key control on atmospheric CO2 and hence on Earth’s temperature. Knowledge of the influence of discharge and temperature on weathering product loads and fluxes through rivers is important to evaluate the possible influence of climate change on weathering. The role of hydrology on such loads and fluxes is clear, but the effect of temperature is difficult to investigate, particularly in big rivers. We use long term (1974–2015) measurements of hydrological and chemical parameters in 20 Swiss stations in large, median-sized, and small rivers. This is to calculate the effect of discharge and temperature on annual loads in each station and in mean fluxes of silicic acid (SA) and calcium linked to carbonate (Cacar) considering all 20 stations together. SA and Cacar loads are good proxies of carbonate and silicate weathering. Mean annual loads of SA and Cacar depend mostly on discharge. They decrease with temperature when the dependence is evaluated by univariate linear regression. Multiple linear regression analysis, however, reveals that the real influence of temperature, when taking into account discharge, is positive in several cases for SA and is mostly non-significant for Cacar. Runoff and lithology are the main positive factors on SA fluxes, whereas temperature is the main positive factor in Cacar fluxes. In both cases, the fraction of impounded water in the catchment is the main negative influence. No significant temporal trend in loads are detected in 18 out of the 20 stations despite the general increase of water temperature, which is consistent with the small effect of temperature on loads found in the present work.