n. - Water that is present in Earth's major seas and oceans. Sea water naturally has a salty taste due to its salt concentration, which ranges from 35 to 50 parts per thousand (ppt). The salt concentration of sea water is used as a measurement of salinity. Water with a salt concentration less than that of sea water; i.e., less than 35 ppt, is either fresh-water of brackish water. Any water with a salt concentration greater than that of sea water; i.e., greater than 50 ppt, is called brine.