海水既咸又苦，说明海水中含有大量的盐分。海水溶液的百分比浓度，叫做海水的盐度。影响浓度的因素是溶质和溶剂的变化，即盐分和水的变化。海水中盐分的含量基本稳定，所以盐度的高低取决于水的变化，水的变化主要有四种方式：降水、蒸发、径流、结冰。在外海或大洋，影响盐度的因素主要有降水和蒸发。从低纬度到高纬度，海水盐度的高低，主要取决于 Seawater is salty and bitter, indicating that seawater contains a lot of salt. The percentage concentration of seawater solution is called salinity of seawater. The factors that affect the concentration are the changes of the solute and the solvent, ie the change of salt and water. Salt content in seawater is basically stable, so the level of salinity depends on the change of water. There are mainly four ways to change water: precipitation, evaporation, runoff, and icing. In the open sea or ocean, the main factors affecting salinity are precipitation and evaporation. From low latitudes to high latitudes, the salinity of seawater depends mainly on