How Are Ocean Currents Formed?

Ocean currents are the wind- and density-driven movements of ocean water. Ocean currents are invisible forces that transport heat and nutrients from one part of the ocean to the other, influencing the climate and living conditions of many plants and animals.

Effects

• The sun heats the atmosphere, creating wind, which moves the surface of the ocean through friction. The wind's influence does not generally extend below 100 meters.

Significance

• The sun can alter the density of the ocean through evaporation, causing water to cool or become saltier. This cooler, more dense water will sink and warm water will rise, creating thermohaline circulation.

Forces

• The Coriolis Effect is the deflecting force caused by the Earth's rotation that makes the direction of wind and water flow to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Considerations

• The depth of the water, underwater topography, and the extent and location of land all modify the ocean currents generated by the sun and Earth's rotation.

Fun Fact

• The Kuroshio Current, off the shores of Japan, is the largest current. It can travel 40 to 121 kilometers per day at 1.6 to 4.8 kilometers per hour, and extends some 1,006 meters deep.