What is the name of the global ocean circulation system driven by density differences?

The global ocean circulation system driven by density differences is thermohaline circulation. Its name combines “thermo,” referring to temperature, and “haline,” referring to salt content—two factors that determine seawater density.

Cold, salty water becomes dense enough to sink in high-latitude regions, especially the North Atlantic and around Antarctica. This sinking helps form deep-water masses that move through ocean basins, while deep water eventually rises elsewhere, completing a slow overturning cycle.

The circulation transports heat, dissolved gases, nutrients, and salt around the planet. It is often called the global ocean conveyor belt, although that nickname can oversimplify a network involving wind, tides, mixing, and several connected circulation systems.

A common mix-up is confusing thermohaline circulation with the Gulf Stream or the Coriolis effect. The Gulf Stream is primarily a wind- and density-influenced current, while the Coriolis effect deflects moving water; neither name describes the entire global density-driven overturning system.