4 MARINE PRODUCTS OF COMMERCE 



Certain unscrupulous persons have profited from man's cupidity by capitalizing 

 on fake schemes for the extraction of gold and silver from sea water. Carefully 

 conducted studies have shown that it is possible to separate gold from sea water, 

 but that the cost is hundreds of times greater than the value of the gold obtained. 



The quantities of the more abundant chemicals found in the entire ocean are so 

 great as to be beyond comprehension. Even the amount of salts in a cubic mile 

 of sea water is almost beyond our understanding, as shown in Table 3. 



Table 3. The More Abundant Compounds (Hypothetical Combinations) 

 AND Elements in One Cubic Mile of Sea Water.* 



Sodium chloride 128,284,403 tons 



Magnesium chloride 17,946,522 



Magnesium sulfate 7,816,053 



Calcium sulfate 5,934,747 



Potassium sulfate 4,068,255 



Calcium carbonate 578,832 



Rhubidium 64,316 



Fluorine 1,400 



Barium 916 



Zinc 450 



Iodine a minimum of 90 



Arsenic 46 to 368 



Phosphorus up to 400 



Nitrogen up to 1300 



It is noteworthy that, with the exception of oxygen, the most abundant elements 

 in igneous rocks, silicon, aluminum, and iron, are present in only very small 

 amounts in sea water. Thus, the relative abundance of the elements in sea water 

 is far different from that in the earth's crust. 



The composition of the dissolved substances in river water is quite different 

 from that of the sea. It is probable that factors operating in the ocean itself, 

 such as solubility, physical-chemical reactions, and biological activity (Sverdrup, 

 Johnson, and Fleming, 1946), control the concentrations of many of the elements 

 that are potentially available in large amounts. The solubility of certain compounds 

 of some elements may limit the concentration of these elements. Additional 

 amounts of these elements brought to the ocean in solution in river water will be 

 removed by chemical precipitation. The quantities of other elements may be 

 limited by physical-chemical processes more complex than the precipitation of 

 some simple salt, as, for example, the reactions that may take place between the 

 dissolved substances and the colloidal and finely divided material introduced by 

 the rivers. Such processes include ionic adsorption, base exchange, and the forma- 

 tion of complex minerals. 



Biological activity is undoubtedly of great importance in controlling the con- 

 centrations of many of the elements in the ocean. For example, the growth of 

 plants in the surface layers greatly reduces the quantity of nitrates and phosphates; 

 however, these compounds tend to accumulate in the comparatively stagnant 

 abyss. A large proportion of marine animals use phosphate and carbonate of 



" Taylor, H. F., "Resources of the Ocean," /. Franklin Inst., 214, 167-196 (1932). 



