Ocean Current

An ocean current is a current that flows more or less permanently in one of the Earth's oceans.

Ocean currents may flow for thousands of kilometers. They are very important in determining the climates of the continents bordering on the oceans they flow in. The most striking example is the Gulf Stream, which makes north-west Europe much more temperate than any other region at the same latitude. However the importance of currents is also illustrated by the El Niņo effect, in which the temporary reversal of an ocean current causes devastating climatic change in South America, whose effects spread as far as Australia.

Ocean currents are also very important in the dispersal of many life forms. A dramatic example is the life-cycle of the eel.