长江口主要阳离子随盐度变化的研究

Variation of major cations against salinity in the Yangtze River estuary

摘要: 以追踪混合水团的方式采样,并测定了长江河口混合区表层和底层中主要阳离子Mg²⁺、Ca²⁺、Na⁺和K⁺的浓度,讨论了长江口水体的pH分布特征和主要阳离子的混合特征.结果表明,长江口水体的pH状况受人为污染影响较小,河口混合区主要阳离子的浓度随着水体盐度的增大而增大,Ca/Mg比值随水体盐度的增大而迅速减小,且主要阳离子浓度相对于盐度的变化在表层和底层水体间没有显著的差别.在长江河口混合区主要阳离子的浓度及其比值随盐度的变化可用线性混合模型进行较好地预测和模拟.

Abstract: Surface and bottom water samples in the Yangtze River estuary were collected in the summer of 2001,following estuarine mixing procedure.Major ions Mg²⁺,Ca²⁺,Na⁺ and K⁺ are determined.The results show that pollution has litt le in fluence on pH situation in the Yangtze River estuary.Concentrations of major ions in mixing zone increase with salinity and the ratio of dissolved Ca/Mg decrease.Change in major ions in the Yangtze River estuary can be simulated by a linear mixing model between riverine and sea waters.There is no obvious difference between surface and bottom waters in major ion compositions.