What is a primary factor in the formation of gyres in the ocean?

The formation of gyres in the ocean is primarily influenced by Earth's rotation, a phenomenon known as the Coriolis effect. As the Earth rotates, the movement of water is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deflection is crucial in creating the circular patterns of flow seen in gyres.

Wind patterns do play a significant role in driving surface ocean currents, which contribute to the formation of gyres; however, it is the Coriolis effect, resulting from Earth's rotation, that establishes the distinct circular motion characteristic of these gyres. The interaction between the wind and the Coriolis effect shapes how currents travel and ultimately forms the larger gyres in the ocean.

Factors such as the Sun's heat are important for driving atmospheric and oceanic circulation but are not the direct cause of the circular motion seen in gyres. Continental drift influences the configuration of ocean basins but occurs over geologic timescales and does not directly impact the formation of current patterns in the short to medium term. Thus, Earth's rotation is the fundamental force that dictates the structure and behavior of large-scale ocean currents and gyres.