Migration of Inorganic Carbon in Groundwater Evaporation Discharge Areas——A Case Study of Hohhot Basin
The carbon-related water-rock interactions occurring in groundwater evaporation discharge areas have a significant impact on the terrestrial carbon cycle.However,there is limited research on the migration and transformation of dissolved inorganic carbon(DIC)during the groundwater evaporation discharge processes.This study,taking the Hohhot Basin in Inner Mongolia as an example,established a carbon balance equation in groundwater evaporation discharge areas using the principle of mass conservation and hydrogeochemical simulation methods.It aimed to analyze the mechanisms behind the DIC migration and transformation during groundwater evaporation.Results indicate that the evaporation discharge area in the Hohhot Basin acted as a"carbon sink",releasing carbon to the atmosphere at a rate of 7.4 g/(m2·a),while the rates of carbon sequestration through calcite precipitation and DIC entering groundwater are 37.1 g/(m2·a).The calcite precipitation and dolomite dissolution were the primary water-rock interactions controlling the DIC migration and transformation in the groundwater evaporation discharge area.The calcium released from the dolomite and plagioclase dissolution effectively promoted the calcite precipitation,significantly contributing to the groundwater becoming a carbon sink in this region.
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