Conversely, sea ice absorbs heat as it melts. These areas therefore tend to represent large heat exchanges between the ocean and atmosphere. When sea ice drifts away from its region of formation, heat and freshwater are redistributed. Since heat is released at regions of ice formation and heat is absorbed at the location where the ice melts, the transport of heat is in a direction opposite to the ice drift. Since the ventilation of the global ocean is partly controlled by the water properties of the Arctic-North Atlantic connection, the transport of sea ice into it plays an important role in ocean circulation.
Sea ice restricts the flow of all of the items listed.
Sea ice formation releases heat during freezing conditions, and the melting of sea ice absorbs heat. This results in a moderation of temperature extremes. Salt rejection during the formation of sea ice is a distillation process. It acts as a seawater filter, allowing only a fraction of the initial salt content to become captured within the ice. As water changes its state from a liquid to solid, the energy requirements necessary to maintain the new solid form are decreased.