Ocean Water

Looking at the salts and elements that comprise seawater
“The ocean is the Earth’s greatest storehouse of minerals,” Rachel Carson wrote in The Sea Around Us. “In a single cubic mile of sea-water there are, on the average, 166 million tons of dissolved salts, and in all the ocean water of the Earth there are about 50 quadrillion tons.”As you might expect, sodium chloride (NaCl, common salt) is the most abundant salt in the ocean, making up 77.8 percent of the total salts. Magnesium chloride (MgCl_{2) is next, at 10.9 percent; then magnesium sulfate (MgSO4) at 4.7 percent, calcium sulfate (CaSO4) at 3.6 percent, and potassium sulfate (K2 SO4) at 2.5 percent. All the other salts combined comprise the last 0.5 percent.More than 50 of the known elements, including gold, have been identified in seawater. The following list shows the number of grams of various substances in every kilogram (1,000 g) of water at a salinity of 35 parts per thousand: chloride, 19.4; sodium,10.8; sulfate, 2.70; magnesium, 1.3; calcium, 0.4; potassium, 0.4; bicarbonate, 0.1; bromide, 0.067; strontium, 0.008; boron, 0.004; and fluoride, 0.001.See also Drinking Seawater.}