Follow the giant rivers of moving seawater that connect the world's oceans.
Ocean currents are large movements of seawater that transport heat, nutrients, organisms, and other materials around the planet. Some currents move mainly near the surface, while others form deep within the ocean.
Learn how winds help push ocean water across enormous distances.
Learn MoreDiscover how temperature and salt can help move water through the deep ocean.
Learn MoreExplore the huge rotating current systems found in major ocean basins.
Learn MoreSee how our rotating planet influences moving air and water.
Learn MoreLearn how moving seawater carries heat from one region to another.
Learn MoreDiscover why rising deep water can create productive marine ecosystems.
Learn MoreSee how scientists use floats, satellites, ships, and instruments to track water.
Learn MoreWinds blowing across the ocean transfer energy to the water and help create surface currents. Continents redirect these currents, producing recognizable patterns across the major ocean basins. Surface currents can transport warm tropical water toward higher latitudes and colder water toward warmer regions.
Deep-ocean circulation is influenced by differences in water density. Colder or saltier seawater can be denser and may sink beneath warmer or fresher water. This movement contributes to a global system that connects different parts of the ocean over long periods.
A gyre is a large system of rotating ocean currents. Major gyres form in the Atlantic, Pacific, and Indian oceans as winds, Earth's rotation, and continents guide moving water. These systems influence marine ecosystems, weather patterns, shipping, and the movement of floating material.
Because Earth rotates, moving water does not travel across the planet in perfectly straight paths. This apparent turning effect is called the Coriolis effect. It contributes to the direction of large-scale current systems and acts differently in the Northern and Southern Hemispheres.
The ocean stores and transports enormous amounts of heat. Warm currents can help make nearby coastal regions milder, while cold currents can cool nearby air and influence rainfall patterns. Ocean circulation is therefore an important part of Earth's climate system.
Upwelling occurs when deeper water rises toward the surface. Deep water can contain nutrients that support the growth of phytoplankton when they reach sunlit waters. This can support rich food webs and important fishing regions.
Oceanographers measure currents with drifting buoys, robotic floats, ships, satellites, and instruments anchored beneath the surface. Researchers can track water temperature, salinity, speed, direction, and depth. These observations help improve our understanding of weather, climate, marine ecosystems, and navigation.