Why is the temperature and salinity of ocean surface waters changeable?

The temperature and salinity of the surface waters of the ocean are significantly influenced by the melting of ice and glaciers, the influx of chilled and unsalted water from rivers, the currents of the ocean itself. The greatest changes in temperature and salinity of water occur due to the fall of a huge amount of precipitation. With an excessive amount of precipitation, the salinity of the ocean can change from five percent to three percent. At high temperatures, the water evaporates and more salt remains in the ocean. When exposed to cyclones, cold winds cool the ocean surface.