Currents Giant streams of water that flow in the ocean 2 major types Surface: caused by wind Deep: caused by density/gravity
Surface Currents This results in giant circular patterns called gyres Gyres rotate clockwise in the northern hemisphere and counterclockwise in the southern hemisphere Created and maintained by wind Generally move from east to west near the equator Move west to east nearer to the poles
Surface Currents The Kuroshio Current Carries water out of the South China Sea north along the shore of Asia and then east across the far N. Pacific The Gulf Stream Carries water out of the Gulf of Mexico north along the shore of N. America and then east across the far N. Atlantic
Surface Currents North Pacific Drift Very slow current that carries water across the northern part of the Pacific Ocean, from west to east. West Wind Drift Very slow current that carries water around the world in the far southern hemisphere, from west to east
Surface Currents North Pacific Gyre General clockwise rotation of the Pacific Ocean, north of the equator. Near the center is relatively calm, current free water There is NOT a giant garbage island in the middle of this Gyre, BUT there is a lot of microscopic plastic pollutants in the water.
Surface Currents North Atlantic Gyre General clockwise rotation of the Atlantic Ocean, north of the equator. Near the center is calm current free water called the Sargasso Sea The Sargasso Sea is NOT a solid mass of seaweed that mysteriously clears ships of their crews.
Deep Currents Very slow moving currents that are caused by differences in density The deepest is the Antarctic Bottom Water Very cold water = very dense water Freezing water off the surface leaves very saline water behind = very dense water This super-dense water sinks to fill the deepest parts of the ocean This current is very slow
Deep Currents North Atlantic Deep Water Similar to the Antarctic Bottom water, but slightly less dense Floats on top of the Bottom water and the current carries it down almost to Antarctica The deep currents provide a foundation of water for the surface currents to ride over. Movement of the surface water causes upwelling, which brings the deep water up to the surface.