Factors Controlling Chemical Composition of Seawater Input and Output Fluxes

4 Factors Controlling Chemical Composition of Seawater (Input and Output Fluxes) 

Chemical composition of seawater is controlled by various processes. River water input and sedimentation have been considered as important processes controlling chemical composition of seawater. However, there are other processes controlling chemical composition of seawater. They are seawater cycUng at mid-oceanic ridge, input of volcanic gas, evaporation, weathering of oceanic cmst, aerosol fall, anthropogenic pollution etc. (Wolery and Sleep 1976 Holland 1978). 

Input of river water to seawater is the most important process controlling chemical composition of seawater. Chemical composition of river water varies widely (Table 4.4). Thus, it is difficult to estimate average chemical composition of river water in the world. However, it can be regarded as average chemical composition of major river water in continent (Missippi, Naile, Yangtze river etc.). Chemical composition of major river water is determined by water-rock interaction, mixing 

Component Japanese 225 average riverwater Kobayashi (1960) Japanese 42 average riverwater Sugawara (1967) Average world Livingstone (1963) Average world Martin et al. (1979) As suspended solid Martin et al. (1979) 

Recently, detailed studies on the factors controlling river water chemistry such as biological activity (Likens et al. 1987), soilwater (Holland 1978 Likens et al. 1987) and geography (Drever 1988) have been done. However, the chemical compositions of major river water plot in chemical weathering-dominated region. 

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