δ¹³ C-Δ¹⁴ C 探究黄土高原治沟造地区水库溶解性无机碳的迁移转化过程

Reservoirs are constantly involved in material exchange between terrestrial and aquatic ecosystems, where dissolved inorganic carbon (DIC) plays an important role in global and regional carbon cycling. In order to reveal the source and the migration transformation process of DIC in reservoirs after consolidated activities, the physicochemical parameters and the DIC content of water in the Gutun reservoir near a newly-built cropland of the Loess Plateau were measured in summer and winter, and the source of DIC was traced by using dual carbon isotopes (δ¹³C-Δ¹⁴C). The results showed that the DIC content of the reservoir water was(30. 3±5)and(32. 4±2. 7)mg / L in summer and winter, respectively, with small differences. The mean values of δ¹³C_DIC and Δ¹⁴C_DIC of the reservoir water were -8. 23‰±1. 88‰ and -233. 96‰± 93. 89‰ in summer and -9. 56‰±1. 05‰ and -315. 99‰±96. 06‰ in winter, respectively, and the winter values were more negative than the summer values. In summer, the main source of DIC in the reservoir water was nearby soil, with a contribution of 47%, and sediment pore water, atmosphere and inlet water were secondary contributing sources; in winter, the main sources of DIC in the reservoir water were inlet spring water and the nearby soil, with contributions of 35% and 30%, respectively, and sediment and pore water was the secondary contributing source. In both winter and summer, the contribution of nearby soil to DIC of the reservoir water was not negligible.