Table 1 

 The Most Abundant Ions in Seawater* 



*Values of g/kgm of seawater/chlorinity seawater; taken 



from Millero (1973a,b). 

 tFor 357^„ salinity or 19.374°/^ chiorinity seawater; taken 



from Millero (1973a,b). 



5. Chemical and structural analysis of intermediate natural materials 

 in the iron-sulfur and similar systems 



6. Use of information and materials in 4 and 5 and experiments in 

 1-3. 



Since the oceans have nearly a constant composition of constituents, 

 reactions must be occurring nearly equally everywhere (unlikely) or 

 at rates slower than mixing rates (hkely). When we ask the question, 

 "Where do these reactions take place?" we come up with several an- 

 swers, and each answer raises a question. Consider the reactions listed 

 in Table 2. 



Reaction 1. About 10^^ moles of CaCOs are precipitated in the 

 oceans yearly. The majority of this precipitation in near-surface pelagic 

 areas as a result of biological activity; lesser amounts are biologically 

 precipitated on continental shelves and on coral reefs. Although the 

 near-surface layers of the ocean are invariably super-saturated with 

 CaCOa, there is little evidence for chemical precipitation of this com- 

 pound. This problem is discussed by Chave and Seuss (1970) and 

 Pytkowicz (1965). Another problem concerned with Reaction I is that 



8 



