of sea water decreases with increasing salinity and is about at 35 g/l. Salinity Element Percent Element Percent Oxygen 85.84 Sulfur 0.091 Hydrogen 10.82 Calcium 0.04 Chlorine 1.94 Potassium 0.04 Sodium 1.08 Bromine 0.0067 Magnesium 0.1292 Carbon 0.0028 Although the vast majority of seawater has a salinity of between 3.1% and 3.8%, seawater isn't uniformly saline throughout the world. Where mixing occurs with fresh water runoff from river mouths or near melting glaciers, seawate… (More on Seawater)