Why is the sea salty?
The rivers and the oceans that feed them have different compositions. Calcium is predominant in rivers, and sodium and chlorine in oceans, in the form of dissolved salt. Calcium is rapidly removed from ocean water by marine organisms, such as clams and corals. Sodium is removed by clay particles, but much more slowly. This is why the sea is salty.
Polar ice and climate
Polar ice affects the climate by reflecting more solar radiation, and thus more heat, than land or water. In addition, ice affects climate by removing fresh water from, or supplying it to, the polar seas through freezing and melting. For example, as sea ice forms, the salt content of the cold surface water increases, making it denser and causing it to sink. The cold deep water flows south, drawing warm surface water from the tropics northward to replace it. This transport of heat from the equator to the poles warms the northern latitudes.
Topic: Earth Science
Keywords: Salinity, Sodium, Chlorine, Oceanography, Calcium, seawater