Which factors contribute to the formation of ocean currents?

The formation of ocean currents is influenced by several interrelated factors, among which earth rotation and salinity variations play a crucial role.

Earth's rotation affects ocean currents through the Coriolis effect, causing moving water to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deflection alters the direction of currents and contributes to the establishment of large-scale ocean circulation patterns known as gyres.

Salinity variations are another critical factor because they influence water density. Differences in salinity and temperature create density gradients in the ocean, which drive thermohaline circulation—also known as the global conveyor belt. This circulation is essential for nutrient distribution and temperature regulation across the oceans.

While wind patterns do influence surface currents and play a significant role, they are not the only factor at play. Sunlight exposure primarily affects surface temperature and biological processes but does not directly drive currents. Fish migration patterns are more about biological behaviors and do not contribute to the physical movement of ocean water.

Thus, the correct answer highlights two primary mechanisms—earth rotation and salinity variations—that combine to create and sustain ocean currents.