三门峡库区湿地水体氢氧同位素变化特征研究

Study on the Variation Characteristics of Hydrogen and Oxygen Isotopes in Wetland Water in Sanmenxia Reservoir Area

湿地水文过程控制着湿地的形成与演化。三门峡库区湿地是典型的多泥沙河流湿地,对黄河中游河道水沙调节和生物多样性具有重要意义。为研究三门峡库区湿地的水文循环特征,基于稳定同位素技术,采集河流水、地下水、土壤水样品,测定各类水体中稳定氢氧同位素δD和δ^(18)O的含量,分析三门峡库区湿地不同水体的氢氧同位素变化特征。结果表明:①三门峡库区湿地内土壤水中的稳定氢氧同位素含量最高,河流水中的次之,地下水中的最低。②河流水中的氢氧同位素含量2018年蓄水期的最高,2020年泄水期的最低,地下水和土壤水泄水期的氢氧同位素含量均高于蓄水期的。③河流水、地下水和土壤水中δ^(18)O和δD的相关关系分别为:δD=6.342δ^(18)O-2.873、δD=4.928δ^(18)O-19.425和δD=6.390δ^(18)O-3.588,各类水体拟合方程的斜率和截距均小于当地大气降水线,说明这些水体均受到大气降水的补给。该研究结果可为湿地水循环理论和湿地生态保护提供科学支撑。

The formation and evolution of wetlands are controlled by wetlands′hydrological processes.The wetland in the Sanmenxia Reservoir area is a typical river wetland with heavy sediment,which is significant for sediment regulation and biodiversity in the middle of the Yellow River.To research the hydrogen and oxygen isotope characteristics,based on stable isotope technology,samples of river water,groundwater and soil water in Sanmenxia Reservoir wetland were collected to measure the contents of stable hydrogen and oxygen isotopesδD andδ^(18)O in various water bodies.According to the data,the results are as follows:①Soil water has the highest concentration of stable hydrogen and oxygen isotopes,followed by river water,and groundwater has the lowest concentration.②River water had the highest concentrations of hydrogen and oxygen isotopes during the storage period in 2018,and the lowest during the discharge period in 2020.The hydrogen and oxygen isotope contents of groundwater and soil water were higher during the discharge period than in the storage period.③The connection betweenδ^(18)O andδD in river water,groundwater and soil water is respectively as follows:δD=6.342δ^(18)O-2.873,δD=4.928δ^(18)O-19.425,δD=6.390δ^(18)O-3.588.The fitting equations of water body have a lower slope and intercept than local atmospheric precipitation lines,those indicate that atmospheric precipitation is the primary recharging source for these water bodies.The results provide a scientific support for the theory of wetland water cycle and the protection of wetland ecosystems.