14 GOLDBERG [CHAP. 1 



higher than the calculated ones ; a result not unexpected if these metal ions 

 engage in complex formation with such anionic species as chloride and sulfate. 

 A most important deduction is that there can be little doubt that the con- 

 centrations of the tabulated metal ions, excluding calcium, strontium and 

 possibly barium in deep waters, cannot be controlled by solubility equilibria. 

 Finally, there is a respectable correlation between the residence times and the 

 ratio of measured maximum concentration to the observed concentration in 

 sea-water, an indicator of the degree of undersaturation. 



These reactivity considerations have been concerned with metallic ions 

 which have been derived from rock- weathering processes. These concepts may 

 also be applied to the dissolved gases that enter the oceans via the atmos- 

 phere. The chemical passivity of the dissolved rare gases and nitrogen is 

 reflected in the fact that they subsequently undergo little, if any, concentration 

 changes in their water-masses. However, dissolved gaseous oxygen is found 

 often in highly undersaturated states, and is even absent in some water, owing 

 to its highly reactive nature in the biochemical cycles of the sea. 



With the background of relative reactivities as ascertained by residence 

 times and degrees of undersaturation, we can now attempt to seek out some of 

 the inorganic and biochemical processes that regulate the intriguing chemical 

 make-up of sea-water. 



3. Chemical Reactions in the Oceans and the Composition of the End- 

 Products 



Although many chemical reactions proceed in the marine environment with 

 rates at which discernible amounts of material accumulate on a square centi- 

 meter of sea floor in times of the order of hundreds or thousands of years, 

 nonetheless, the very nature of the end-products or the chemical species within 

 them can be decisive in reconstructing the chemical system in which they 

 formed. 



Krumbein and Garrels (1952), for example, have pointed out that marine 

 phosphorites probably form in restricted basins in which the pH is relatively 

 low, i.e. environments near or at anaerobism with pH values below 8, slightly 

 less than that of normal sea- water. These minerals have the general formula 

 Caio(P04, C03)eF2-3 in which the excess positive charges resulting from the 

 substitution of carbonate for phosphate are compensated by excess fluorine or 

 hydroxyl groups. Extensive deposits occur on the sea-floor of southern 

 California where an area of about 6000 square miles contains phosphorite in 

 the forms of nodules, slags and oolites (Emery, 1960). Emery also notes that 

 about 98% of the material is in water depths from 100 to 1000 ft and that 

 foraminiferal sands are often associated with the deposits. 



Several recent investigations tend to confirm the hypothesis of Krumbein 

 and Garrels. Altschuler, Clarke and Young (1958) find that the uranium in 

 southern Californian phosphorites exists in the tetravalent state to the extent 

 of 55 to 74% of the total uranium. The reduced uranium occurs in the apatites 



