Formation of Sea Ice
Fresh water freezes at 32° Fahrenheit (0° Celsius). Seawater freezes at about 28.4° F (-2 ° C) because of the salt content. However, when seawater freezes, the ice that forms contains very little salt. Only the water part freezes, the remaining salt is concentrated as brine that separates from the sea ice. This process is very important for deep-sea circulation.