珠江口表层水中主要常量离子的研究

Study on Major Ions in the Surface Water of Zhujiang Estuary

９９４年９月采集了珠江口表层海水水样，并对其溶解态的Ｋ＋、Ｎａ＋、Ｃａ２＋、Ｍｇ２＋、ＳＯ２－４、Ｃｌ等化学要素进行了测定。结果表明，珠江口调查海域表层水中溶解态的Ｋ＋、Ｎａ＋、Ｃａ２＋、Ｍｇ２＋、ＳＯ２－４主要受陆源淡水与外海水物理混合稀释的影响，与Ｃｌ具有良好的直线正相关；Ｃａ２＋／Ｃｌ、ＳＯ２－４／Ｃｌ明显高于大洋水相应比值，Ｎａ＋／Ｃｌ、Ｍｇ２＋／Ｃｌ略高，而Ｋ＋／Ｃｌ比大洋比值低；在与中国其它各主要河口表层水对应Ｃｌ比较中，珠江口的ＳＯ２－４／Ｃｌ较高，而Ｃａ２＋／Ｃｌ，Ｍｇ２＋／Ｃｌ比值居低；上述各主要常量离子和Ｃｌ的等值线均沿自北向南走向递增。

Zhujiang Estuary is a mixing zone of seawater with fresh water which influxes from Dongsimen, i.e., Hu Men, Jiao Men, Hong Qili and Heng Men. Surface seawater samples in Zhujiang Estuary were collected in September 1994 and their chemical parameters such as the dissolved forms of K +, Na +, Ca 2+ , Mg 2+ , SO 2- 4, and Cl were measured in order to study the chemical characters of the surface water in this region. The results indicate that the concentrations of K +, Na +, Ca 2+ , Mg 2+ and SO 2- 4 in the surface water are mainly affected by the physical mixing dilution of land fresh water with seawater, and they show obvious positive linear correlations with Cl: the Ca 2+ /Cl and SO 2- 4/Cl ratios are obviously higher than those in the open ocean and the Na +/Cl and Mg 2+ /Cl ratios are a little higher whereas the K +/Cl ratio is lower than those in the open ocean; the SO 2- 4/Cl ratio is higher while the Ca 2+ /Cl and Mg 2+ /Cl ratios are lower in comparison with those in the other main estuaries in China; the concentrations of the major ions mentioned above and Cl all increase from north to south.