滴水湖湖水主要离子组成及时空变化特征

Major ions composition and spatiotemporal variation of water in Dishui Lake

摘要:

2009年1月至12月每两周对滴水湖主要离子进行调查分析，结果显示：滴水湖湖水全年离子总量平均值为1.82 g/L，属于微咸水，主要阴阳离子分别为Cl^-与Na⁺，水质类型为Cl^Na_Ⅲ。2009年湖水年内离子总量逐渐降低，离子组成亦发生了显著的变化，其中Cl^-、Mg²⁺ 的比例不断降低、HCO₃^-、SO₄^2-, Ca²⁺的比例则逐渐升高。不同湖区离子总量存在显著差异，水上运动俱乐部断面最高、南岛断面最低，但各湖区之间离子组成则无显著差异。分析各采样点的离子总量与组成的相关性可知，离子总量越高，Cl^-所占比例越高，HCO₃^-所占比例越少，滴水湖的水质类型与长江下游其他湖泊及天然微咸水湖具有显著差异。试验获得了滴水湖离子的总量、组成及时空变化等重要的基础数据，为滴水湖今后的水化学与水生态研究奠定了良好的基础。

Abstract:

Through measuring major ions of Dishui Lake water every two weeks from January to December in 2009, we concluded that the average total ion content of the lake was 1.82 g/L and the water of Dishui Lake was brackish.The major anion and cation were Cl^- and Na⁺ respectively. The water type was Cl^Na_Ⅲ according to Alekin classification. The total ion content decreased gradually in 2009, and the ion composition of the lake changed significantly with the proportions of Cl^- and Mg²⁺ decreasing and HCO₃^-, SO₄^2-, Ca²⁺increasing. Significant difference lay in the total ion contents among different sampling sites. The area around water sports club had the highest total ion contents while the lowest site was South Island district. As to the ion composition, no significant difference was observed among five sampling sites. Analyzing the relationship between the ion composition and total ion content in Dishui Lake, we concluded that the higher total ions concentration, the larger the proportion of Cl^- and the less the proportion of HCO₃^-. The water type of Dishui Lake was significantly different from other lakes in the lower reaches of the Yangtze River and common natural brackish lakes. The important information about total ions, ion composition and spatiotemporal variation of Dishui Lake were obtained which laid a good foundation for water chemistry and ecological research in the future.