TY - JOUR
T1 - Isotopic and Chemical Constraints on the Biogeochemistry of Dissolved Inorganic Carbon and Chemical Weathering in the Karst Watershed of Krka River (Slovenia)
AU - Zavadlav, Saša
AU - Kanduč, Tjaša
AU - McIntosh, Jennifer
AU - Lojen, Sonja
N1 - Funding Information:
Acknowledgments This study was financially supported by the Slovenian Research Agency, contract PR-02497 of the Young Researchers Programme, research project J1-9498 and research programme P1-0143. The authors thank Mr. Stojan Zˇigon and Dr. Martina B. Sˇturm for analytical support. Special thanks are given to Mr. Anthony Byrne for linguistic corrections and two anonymous reviewers for the critical and constructive comments on the manuscript.
PY - 2013/5
Y1 - 2013/5
N2 - The hydrogeochemical and carbon isotope characteristics of the Krka River, Slovenia, were investigated to estimate the carbon transfer from the land ecosystem in the watershed. During the 3-year sampling period (2008-2010), temperature, pH, electrical conductivity, major ion content, dissolved inorganic carbon (DIC) and dissolved organic carbon content, and the isotopic composition of DIC (δ13CDIC) were monitored in the main stream of the Krka River and its tributaries. The major solute composition of analysed waters is dominated by an input of HCO3-, Ca2+ and Mg2+ originating from carbonate dissolution. The Mg2+/Ca2+ and Mg2+/HCO3- molar ratio values ranging from 0. 24 to 0. 71 and 0. 05 to 0. 30, respectively, indicate a high degree of dolomite dissolution relative to calcite. Dissolved CO2 concentrations in the river were up to tenfold supersaturated relative to the atmosphere, resulting in supersaturation with respect to calcite and degassing of CO2 downstream. The δ13C values in river water range from -15. 6 to -9. 4 ‰ and are controlled by the input of tributaries, exchange with atmospheric CO2, degradation of organic matter, and dissolution of carbonates. The mass balance calculations for riverine DIC suggest that the contribution from carbonate dissolution and degradation of organic matter have major influence, whereas the exchange with atmospheric CO2 has minor influence on the inorganic carbon pool in the Krka River.
AB - The hydrogeochemical and carbon isotope characteristics of the Krka River, Slovenia, were investigated to estimate the carbon transfer from the land ecosystem in the watershed. During the 3-year sampling period (2008-2010), temperature, pH, electrical conductivity, major ion content, dissolved inorganic carbon (DIC) and dissolved organic carbon content, and the isotopic composition of DIC (δ13CDIC) were monitored in the main stream of the Krka River and its tributaries. The major solute composition of analysed waters is dominated by an input of HCO3-, Ca2+ and Mg2+ originating from carbonate dissolution. The Mg2+/Ca2+ and Mg2+/HCO3- molar ratio values ranging from 0. 24 to 0. 71 and 0. 05 to 0. 30, respectively, indicate a high degree of dolomite dissolution relative to calcite. Dissolved CO2 concentrations in the river were up to tenfold supersaturated relative to the atmosphere, resulting in supersaturation with respect to calcite and degassing of CO2 downstream. The δ13C values in river water range from -15. 6 to -9. 4 ‰ and are controlled by the input of tributaries, exchange with atmospheric CO2, degradation of organic matter, and dissolution of carbonates. The mass balance calculations for riverine DIC suggest that the contribution from carbonate dissolution and degradation of organic matter have major influence, whereas the exchange with atmospheric CO2 has minor influence on the inorganic carbon pool in the Krka River.
KW - Biogeochemical processes
KW - Carbonate weathering
KW - Dissolved inorganic carbon
KW - River
KW - Stable carbon isotopes
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U2 - 10.1007/s10498-013-9188-5
DO - 10.1007/s10498-013-9188-5
M3 - Article
AN - SCOPUS:84876422853
SN - 1380-6165
VL - 19
SP - 209
EP - 230
JO - Aquatic Geochemistry
JF - Aquatic Geochemistry
IS - 3
ER -