Ocean current

Ocean current refers to a large flow of seawater that moves through the ocean in a steady direction. Currents can travel near the surface or deep under the water. They act like slow-moving rivers inside the ocean. These moving waters help spread heat, carry nutrients, and support many forms of sea life.

Surface currents are ocean currents that flow near the top of the water. They are mainly moved by wind, which pushes the surface of the ocean and causes the water to drift in a certain direction. Because wind patterns stay fairly steady, surface currents also tend to follow steady paths. These currents can move warm or cool water from one place to another, shaping weather in coastal areas.

Deep currents flow far below the surface. They move more slowly and are driven by changes in water temperature and water density, which means how heavy something is for its size. Cold water is heavier than warm water, so it sinks and begins to move along the ocean floor. When cold water sinks, warm water rises to replace it, creating a cycle that helps keep the ocean always moving.

Ocean currents also help carry nutrients. Nutrients are tiny natural substances that plants and animals need to grow. When deep currents rise toward the surface, they can bring nutrients from the ocean floor to places where sunlight reaches the water. This helps tiny plants called phytoplankton grow. Many small animals feed on phytoplankton, so currents help start food chains in the sea.

Currents affect animals as well. Some fish and sea turtles use currents to travel long distances while saving energy. Currents can also help young animals spread to new areas where they can grow safely. Because currents move heat around the world, they influence where animals can live.

People study ocean currents to learn how the ocean changes over time. Ships, buoys, and underwater tools help scientists see where water is moving. Understanding currents helps people predict storms, plan sea travel, and learn how ocean life depends on moving water.