Dissolved in the surface sea, carbon can be carried in ocean currents around most of the globe. Eventually it may reach the polar regions.
Strong polar winds blow off the frozen land and cool the surface water. Sea ice is formed, leaving most of the salt in the remaining seawater. More carbon dioxide from the atmosphere can also dissolve in the cold water. This cold, salty water is very dense, and has a tendency to sink.
In the North Atlantic, between Greenland and Norway, and the Southern Ocean, near Antarctica, some of the densest waters in the world are formed. Below the pack-ice, the sinking water carries its load of dissolved carbon to the deep ocean floor, where it may remain for hundreds of years, slowly moving in global deep-ocean currents.