Explanation:

Even on the calmest days, Earth's oceans are constantly on the move. At the surface and
beneath, currents, gyres and eddies play a crucial role in physically shaping the coasts and
ocean bottom; in transporting and mixing energy, chemicals and other materials within and
among ocean basins; and in sustaining countless plants and animals that rely on the oceans
for life—including humans.
These features are important components of Earth's global ocean circulation that move
water mainly horizontally. Their effects can also extend down for miles, in some places
reaching the ocean bottom.
Currents are coherent streams of water moving through the ocean and include both long,
permanent features such as the Gulf Stream, as well as smaller, episodic flows in both
coastal waters and the open ocean. They are formed primarily by wind blowing across the
surface of the ocean and by differences in the temperature, density and pressure of water
and are steered by Earth's rotation as well as the location of the continents and topography
of the ocean bottom.
Gyres are spiraling circulations thousands of miles in diameter and rimmed by large,
permanent ocean currents.