The Global Conveyor Belt
The global conveyor belt is a system of ocean currents that transport water around the world. While wind primarily propels surface currents, deep currents are driven by differences in water densities in a process called thermohaline circulation. Density depends on both the temperature (thermo) and salinity (haline) of the water. Along this conveyor belt, heat and nutrients are moved around the world in a leisurely 1000-year cycle.