Vertical Ocean Circulation

The predominant circulation patterns in the open ocean are horizontal ocean currents that affect the upper surface waters, but the vertical circulation of open ocean water masses may be more important for marine life. The nutrient-rich waters encourage the growth of plankton, which serves as the base for the food chain throughout the oceans.

In thermohaline circulation, differences in the temperature, density, and salinity of ocean water masses cause the nutrient-rich deep ocean waters to rise and mix with surface waters. Thermohaline circulation is restricted to polar regions of the northern and southern hemispheres.