COMPOSITION OF SEA WATER The oceans are primarily solutions of metallic salts. Organic materials are present in minute amounts, and atmospheric gases are in solution in varying amounts. The concentrations of dissolved nitrates, phosphates, and silicates are relatively minute and variable and are therefore excluded from ordinary salinity determinations. The chief metallic salts (those of Na, Mg, Ca, K, Sr) are present in such constant proportions that for most purposes a simple analysis of one component, the chloride, is sufficient in any ocean for determination of the total salinity, the specific gravity, and the proportions of various salts. Salinity is defined as “the total amount of solid material in grams contained in one kilogram of sea water when all the carbonate has been converted to oxide, the bromine and iodine replaced by chlorine, and all the organic matter completely oxidized” (Sverdrup, Johnson, and Fleming, 1942, p. 50). It is expressed by the symbol ‰ (parts per thousand). Sets of tables for these determinations, based on the formula, salinity = 0.03 + 1.805 × chlorinity, have been prepared and constitute one of the standard tools of the oceanographer (Knudsen, 1901). The average total salinity of ocean water is about 35‰, but it is slightly different in the various oceans. In the mid-Pacific, for example, the surface salinity is 35.5‰; in mid-Atlantic, 37.0‰, and in the Red Sea it is about 40‰. The Laguna Madre of Texas and the Crimean Sivash are among the saltiest marine lagoons of appreciable size on earth....