has shown that equilibrium models of the ocean may often not apply, 

 in that for the carbon dioxide system, kinetic controls by organisms 

 are more likely than controls by chemical equilibria. To test whether 

 the ocean is in a steady state, or, if not, how the system is approaching 

 equilibrium, it is necessary to identify the chemical reactions that 

 regulate the concentration of each element and to determine the physical 

 chemistry of each reaction. 



Correct specific or generalized concentration-control reactions for 

 the major constituents of seawater probably can be written. Our knowl- 

 edge of the thermodynamics, the kinetics, and the environmental influ- 

 ences on these reactions varies considerably. Some of our ignorance is 

 a result of the natural (biological or chemical) production of thermo- 

 dynamically unstable phases or of extremely slow reactions. 



We cannot state with certainty the concentrations of the minor con- 

 stituents of seawater, let alone define the chemical and physical reactions 

 that control the concentrations. 



To understand the processes and mechanisms governing the inorganic 

 composition, three major questions must be answered. What is the 

 medium of seawater? What kinds of chemical reactions control the 

 composition of seawater? Where do these chemical reactions occur? 



In the following discussion we have attempted to focus on six major 

 topics that should lead to a better understanding of the processes and 

 mechanisms controlling the inorganic composition of seawater. These 

 are (1) seawater as a medium; (2) minor elements; (3) the role of estuaries 

 in modifying the composition of seawater; (4) particulate matter; (5) 

 the role of bottom deposits in modifying the composition of seawater; 

 and (6) numerical models in chemical oceanography. 



Some important areas where information concerning the processes 

 and mechanisms governing the inorganic composition of seawater is 

 needed include the following (National Academy of Sciences, 1971a): 



• Pollution of the environment. Since the ocean is the final reservoir 

 for pollutants, we must have a better knowledge concerning the fate 

 of present and potential pollutants. The introduction of radioactive 

 wastes (such as plutonium) to the marine environment may present us 

 with many new problems. 



• Chemical products from the sea. Although it is not possible at 

 present to recover economically trace constituents from seawater, 

 further work may yield better methods than those presently being used. 



• DesaHnation. With the increasing need for water, new techniques 

 may become available. 



By studying the chemical processes that control the composition of 

 seawater under natural conditions (a dynamic chemical system) and 

 obtaining an understanding of the inputs and outputs (the fluxes), much 

 better estimates can be made for changes that will occur in the oceans. 



