海水碳酸盐体系表观解离平衡常数研究进展

PROGRESS IN STUDIES OF THE APPARENT DISSOCIATION EQUILIBRIUM CONSTANTS OF CARBONATE SYSTEM OF SEAWATER

海洋作为地球表面最大的碳库,在调节大气CO2方面起着非常重要的作用。在海洋碳循环以及涉及海洋酸化问题的研究中,测得海水碳酸盐体系4个参数总碱度(TA)、溶解无机碳(DIC)、二氧化碳分压(pCO2)、pH中的2个,运用热力学方程和平衡常数便可求得海水碳酸盐体系的各个分量。计算中表观解离常数是必需的因子,其准确与否直接决定最后的计算结果。本文介绍了近年来海水碳酸盐体系表观解离常数的研究进展,总结了海水中碳酸表观解离平衡常数的研究测定方法,并且运用文献实测的数据简要比较了不同作者测得的解离平衡常数之间的差异,总结了计算4组参数较优的表观解离平衡常数,以便在海水碳酸盐体系研究中合理选用。

The world ocean plays an important role in atmospheric carbon dioxide regulation as the lar- gest carbon reservoir on the earth surface. The seawater carbonate system can be described with four parameters, i.e., total alkalinity （TA）, total dissolved inorganic carbon （DIC）, partial pressure of CO2（pCO2）, and pH. with the knowledge of two of the carbonate system parameters, the other two parameters and portions of carbonate system can be calculated according to the thermodynamic relations with the appropriate dissociation constants of carbonic acid. The dissociation constants are essential fac- tors which accuracies determine the calculated results of carbonate system. In order to understand the recent progress, studies and determinations of the appropriate dissociation constants of carbonic acid in seawater are focused on, as well as the determination methods of these constants are summarized. The appropriate dissociation constants calculated with the equation of other researchers according to the temperature and salinity from a literature are compared. Four groups of the constants and their applica- bility are evaluated and suggested so as to be chosen reasonably in studies of carbonate system of seawa- ter.