Karnataka dataset
Description
In the manuscript we examined multiple isotopic tracers (δ30Si, 87Sr/86Sr, δ18O and δ2H) in groundwater and surface water from two contrasting watersheds: forested (Mule Hole) and agricultural (Berambadi). Our results indicate that Si isotopic signatures of weathering, adsorption, and plant uptake occurring in the shallow soil and saprolite horizons are partly overprinted and homogenized by the regolith weathering in the deep critical zone, irrespective of land use and seasonality. The addition of our dataset increases the global groundwater δ30Si average from 0.49±0.9‰ (1SD, n=66) to 0.76±0.8‰ (1SD, n=117), emphasizing groundwater heterogeneity and its relevance in continental Si biogeochemical cycling. We conclude that silicon cycling in soil porewaters, and surface waters are directly impacted by land use, while the isotopic composition of groundwater remains unaffected. Our results indicate that Si isotopic signatures of weathering, adsorption, and plant uptake occurring in the shallow soil and saprolite horizons are partly overprinted and homogenized by the regolith weathering in the deep critical zone, irrespective of land use and seasonality.