Sources and transformations of dissolved inorganic carbon (DIC) in springs in tropical high-grade crystalline terrain of Sri Lanka
Hansini K, Senarathne SL, Barth J, Chandrajith R (2026)
Publication Type: Journal article
Publication year: 2026
Journal
Book Volume: 33
Article Number: 101621
DOI: 10.1016/j.gsd.2026.101621
Abstract
An advanced understanding of the factors influencing spring formation, along with an assessment of their geological and geochemical characteristics, is essential for the efficient management of water resources. Because springs directly connect to groundwater, they also serve as natural tracers of subsurface geochemical processes. This study investigates the hydrogeological, geochemical, and isotope characteristics of some selected springs in the high-grade metamorphic terrain of Sri Lanka. Water samples were analysed for major ions (Cl−, NO3−, SO42−, F−, Na+, K+, Ca2+, Mg2+) and some selected trace elements, in addition to stable isotopes of water, inorganic and organic carbon (expressed as δ2H, δ18O, δ13CDIC, and δ13CDOC). The δ18O values ranged from −6.8 to −4.0‰, while δ2H varied from −42.2‰ to −18.9‰. These data matched regional rainfall and indicated their input as the primary recharge mechanism, with slight evaporation. Dissolved inorganic carbon (DIC) concentrations ranged from 0.36 to 11.45 mmol/L, while δ13CDIC values ranged from −27.4 to −13.9‰. Springs located in a more carbonate-dominated terrain showed higher DIC, δ13CDIC, and pH values, indicating increased weathering. Springs in the silicate-dominated terrain are also influenced by soil-derived CO2 and silicate weathering, as evidenced by more depleted δ13CDIC values. Moreover, springs in carbonate-influenced regions showed more than 3-fold higher CO2 flux (up to 13.4 g C m−2 day−1) than those influenced by silicate weathering (4.17 g C m−2 day−1). Silicate weathering under tropical conditions is an important source of DIC and a driver for carbon cycling. The study provides the implications for regional carbon budgets in metamorphic terrains.
Authors with CRIS profile
Sachintha Lakshan Senarathne
Lehrstuhl für Angewandte Geologie
Johannes Barth
Lehrstuhl für Angewandte Geologie
Involved external institutions
Sri Lanka (LK)How to cite
APA:
Hansini, K., Senarathne, S.L., Barth, J., & Chandrajith, R. (2026). Sources and transformations of dissolved inorganic carbon (DIC) in springs in tropical high-grade crystalline terrain of Sri Lanka. Groundwater for Sustainable Development, 33. https://doi.org/10.1016/j.gsd.2026.101621
MLA:
Hansini, Keshmika, et al. "Sources and transformations of dissolved inorganic carbon (DIC) in springs in tropical high-grade crystalline terrain of Sri Lanka." Groundwater for Sustainable Development 33 (2026).
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