**2.2.1 Currents**

Ocean currents, the large scale movement of water, are caused by many sources. One component of the current present in the upper layer of the ocean is due to atmospheric wind conditions at the sea surface. Differing water densities, caused by combining the effect of variation of salinity levels with the exchange of heat that occurs at the ocean surface, cause additional currents known as thermohaline currents, to exist within the ocean. Coriolis forces, forces due to the rotation of the Earth about its axis, also induce ocean currents, while gravitational forces due to other planetary objects, such as the moon and the sun, produce yet another effect on ocean currents (Fossen, 1994, 2002). Combining all of these sources of water current, with the unique geographic topography that are present within isolated coastal regions, leads to highly dynamic and complex currents existing within the world's oceans.
