The cause of ocean currents is primarily driven by a combination of factors, including winds, Earth's rotation, and differences in temperature and salinity of seawater. Surface currents are generated predominantly by wind patterns, creating friction between the air and the ocean surface. Furthermore, the Coriolis effect due to the Earth's rotation influences the direction of these currents. Density gradients caused by variations in temperature and salinity also contribute to deeper ocean currents, known as thermohaline circulation.