{"id":44038,"date":"2025-12-12T11:15:13","date_gmt":"2025-12-12T11:15:13","guid":{"rendered":"https:\/\/www.ampac1.com\/blog\/?p=44038"},"modified":"2026-01-05T11:51:23","modified_gmt":"2026-01-05T11:51:23","slug":"composition-of-seawater","status":"publish","type":"post","link":"https:\/\/www.ampac1.com\/blog\/composition-of-seawater\/","title":{"rendered":"Composition of Seawater"},"content":{"rendered":"

Seawater is a complex solution dominated by dissolved salts, gases, nutrients, trace metals, and organic compounds. Despite geographical variation in salinity, the relative proportions of major ions remain remarkably constant worldwide<\/strong>, a concept known as the Principle of Constant Proportions<\/em>. The majority of seawater salinity is contributed by chloride, sodium, sulfate, magnesium, calcium, and potassium<\/strong>.<\/p>\n

Regional differences mainly occur in semi-enclosed basins and high-evaporation zones (e.g., Arabian Gulf, Red Sea), while open-ocean regions across North America, Europe, and South America exhibit more stable concentrations.<\/p>\n

Major ion composition of seawater (mg\/L):<\/h2>\n

Representative concentration ranges (mg\/L) by global region<\/strong>
Values reflect typical seawater at ~35 PSU; higher-evaporation regions show slightly elevated ion levels.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Major Ion<\/th>\nWest Asia & Middle East<\/th>\nNorth America<\/th>\nNorth Africa<\/th>\nEurope<\/th>\nSouth & Central America<\/th>\nOther (Global Open Ocean)<\/th>\n<\/tr>\n<\/thead>\n
Chloride (Cl\u207b)<\/strong><\/td>\n19,000 \u2013 21,000<\/td>\n18,500 \u2013 19,500<\/td>\n18,800 \u2013 20,000<\/td>\n18,600 \u2013 19,600<\/td>\n18,500 \u2013 19,400<\/td>\n~19,000<\/td>\n<\/tr>\n
Sodium (Na\u207a)<\/strong><\/td>\n10,500 \u2013 11,600<\/td>\n10,200 \u2013 10,800<\/td>\n10,400 \u2013 11,200<\/td>\n10,300 \u2013 10,900<\/td>\n10,200 \u2013 10,800<\/td>\n~10,500<\/td>\n<\/tr>\n
Sulfate (SO\u2084\u00b2\u207b)<\/strong><\/td>\n2,700 \u2013 3,000<\/td>\n2,600 \u2013 2,800<\/td>\n2,650 \u2013 2,900<\/td>\n2,600 \u2013 2,850<\/td>\n2,600 \u2013 2,800<\/td>\n~2,700<\/td>\n<\/tr>\n
Magnesium (Mg\u00b2\u207a)<\/strong><\/td>\n1,300 \u2013 1,450<\/td>\n1,250 \u2013 1,350<\/td>\n1,280 \u2013 1,400<\/td>\n1,260 \u2013 1,360<\/td>\n1,250 \u2013 1,340<\/td>\n~1,300<\/td>\n<\/tr>\n
Calcium (Ca\u00b2\u207a)<\/strong><\/td>\n380 \u2013 450<\/td>\n380 \u2013 420<\/td>\n380 \u2013 430<\/td>\n380 \u2013 420<\/td>\n380 \u2013 410<\/td>\n~400<\/td>\n<\/tr>\n
Potassium (K\u207a)<\/strong><\/td>\n360 \u2013 420<\/td>\n360 \u2013 400<\/td>\n360 \u2013 410<\/td>\n360 \u2013 400<\/td>\n360 \u2013 390<\/td>\n~380<\/td>\n<\/tr>\n
Bicarbonate (HCO\u2083\u207b)<\/strong><\/td>\n120 \u2013 160<\/td>\n110 \u2013 140<\/td>\n115 \u2013 145<\/td>\n110 \u2013 140<\/td>\n110 \u2013 135<\/td>\n~130<\/td>\n<\/tr>\n
Bromide (Br\u207b)<\/strong><\/td>\n60 \u2013 75<\/td>\n60 \u2013 70<\/td>\n60 \u2013 72<\/td>\n60 \u2013 70<\/td>\n60 \u2013 68<\/td>\n~65<\/td>\n<\/tr>\n
Strontium (Sr\u00b2\u207a)<\/strong><\/td>\n7 \u2013 10<\/td>\n7 \u2013 9<\/td>\n7 \u2013 9<\/td>\n7 \u2013 9<\/td>\n7 \u2013 9<\/td>\n~8<\/td>\n<\/tr>\n
Boron (as B)<\/strong><\/td>\n4 \u2013 6<\/td>\n4 \u2013 5<\/td>\n4 \u2013 5<\/td>\n4 \u2013 5<\/td>\n4 \u2013 5<\/td>\n~4.5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Seawater Desalination Systems<\/a>
\nWater Softner<\/a><\/p>\n