What is the primary cause of ocean currents?

The primary cause of ocean currents is related to the interaction of temperature differences within the ocean, but the correct answer emphasizes the physical properties of water in relation to these temperature differences. Cold water, being denser, tends to sink while warm water rises due to its lesser density. This process creates a circulation pattern in the ocean, often referred to as thermohaline circulation, where the movement of these water masses influences global climate and marine life.

While surface winds do play a role in driving surface currents and the Earth’s rotation affects the direction of these currents due to the Coriolis effect, the fundamental driver of the deep ocean currents is primarily the differential heating of the ocean water, leading to changes in density. Therefore, considering the entire scope of ocean circulation, the interaction of temperature and density in water is at the heart of current movement in the oceans.