Since the future of the earth is intimately related to the future of the 

 oceans, it is important to understand the composition of seawater and 

 how this composition affects the processes occurring in the oceans. 



SEAWATER AS A MEDIUM 



Some of the major questions facing chemical oceanography are: 

 How did seawater reach its present composition? How does this com- 

 position affect processes that control the composition of minor com- 

 ponents? Part of the answers are related to the questions, what is the 

 medium of seawater? What are the chemical forms of the major com- 

 ponents? What fluctuations occur? How are the physical and chemical 

 properties of seawater related to the chemical composition? How does 

 the medium of seawater influence various chemical processes occurring 

 in the oceans? Although the answers to some of these questions have 

 been found, many questions still remain and must be answered. In the 

 following section some of the areas that have been studied, and some 

 that need to be studied further are discussed briefly. This discussion 

 will be divided into four major topics: the chemical composition of 

 seawater, the physical and chemical properties of seawater, chemical 

 interactions among the major components, and measurement and 

 prediction of solutes in the medium of seawater. 



The Chemical Composition of Seawater 



Although we know the concentrations of the major components 

 (Lyman and Fleming, 1940; Culkin, 1965; Riley and Chester, 1965; 

 Pytkowicz and Kester, 1969 and 1971) (Table 1), little is known about 

 the mechanisms regulating these concentrations in the oceans and 

 where this regulation occurs. 



From Table 2, it can be seen that thermodynamic and kinetic data 

 on the concentration-controlling reactions for the major dissolved con- 

 stituents of seawater are limited. Furthermore, organic processes are 

 known to influence some of these reactions. To understand the mechan- 

 isms controlling the concentration of more than 99% of the dissolved 

 matter in seawater, it is necessary to study many of the reactions in 

 Table 2. This can be done through \ 



1 . Careful studies of pure systems in the laboratory 



2. Careful studies of "carefully impure" systems in the laboratory 



3. Careful studies of real oceanic situations with as many variables 

 as possible controlled 



4. Chemical and structural analysis of materials (notably alumino- 

 silicates) supplied to the oceans from the land 



