The Ocean

“The edge of the sea is a strange and beautiful place.” ― Rachel Carson

... and a place of dynamic change.

  

Chemical Composition of Seawater & Ocean Chemistry

• water is the "universal solvent" dissolving at least 57 of the 92 elements found in nature.
• most natural elements and the compounds they form are found in the seas as dissolved solids, or solutes.
• seawater = solution/concentration of dissolved solids = salinity
• oceans remain homogenous mixture = ratio of individual salts remain unchanged, despite minor fluctuations in overall salinity.
• ocean chemistry = complex exchanges of seawater, the atmosphere, minerals, bottom sediments, and living organisms.
• mineral-rich water enter the ocean through hydrothermal (hot water) vents in the ocean floor.
• uniformity of seawater = complementary chemical reactions and continuous mixing - ocean basins interconnect, and water circulates among them.
• seven elements account for more than 99% of the dissolved solids in seawater =  chlorine, sodium, magnesium, sulphur, calcium, potassium, and bromine.
• seawater also contain dissolved gases = carbon dioxide, nitrogen, and oxygen.  Also contain suspended and dissolved organic matter, and a multitude of trace elements.
• Average salinity - 3.5% (% parts per hundred) / worldwide 3.4% to 3.7%, attributable to atmospheric conditions above the water and to volume of freshwater inflows.