Ocean currents are continuous, predictable, directional movements of seawater driven by various factors. The following are the main causes of ocean currents:

• Wind: Surface currents in the ocean are driven by global wind systems that are fueled by energy from the Sun. Wind-driven currents generate upwelling currents in conjunction with landforms, creating deepwater currents.

• Density differences: Currents may also be caused by density differences in water masses due to temperature (thermo) and salinity (haline) variations via a process known as thermohaline circulation. These currents move water masses through the deep ocean, taking nutrients, oxygen, and heat with them.

• Tides: Tides create a current in the oceans, which are strongest near the shore, and in bays and estuaries along the coast. These are called "tidal currents." Tidal currents change in a very regular pattern and can be predicted for future dates. In some locations, strong tidal currents can travel at speeds of eight knots or more.

• Gravity: Gravity can also cause ocean currents. Occasional events such as huge storms and underwater earthquakes can trigger serious ocean currents, moving masses of water inland when they reach shallow water and coastlines. Earthquakes may also trigger rapid downslope movement of water-saturated sediments, creating strong turbidity currents.

• Rotation of the Earth: The rotation of the Earth creates wind that agitates the surface and makes waves. These things combined create the ocean as we know it.

The warming and cooling of water masses due to these factors power the currents, which affect the Earths climate by driving warm water from the Equator and cold water from the poles around the Earth.