A current is the large-scale movement of water in a specific direction. In the oceans, currents can be thought of as the Earth's circulatory system, moving vast quantities of waters of different temperatures around the world, creating climates, providing nutrients for marine life, and
http://www.answers.com/topic/what-is-a-current# weather patterns. They may form permanent circulation systems, as in the Atlantic and Pacific oceans or currents can be relatively short-lived, affecting only a limited area-especially along a coastline.