Ocean Currents

Mass movement or flow of ocean water Mass movement or flow of ocean water River within the ocean River within the ocean Two types Two types –Surface and Deep

Ocean Currents move as gyres. A gyre is any large system of rotating ocean currents. Gyres are caused by the Coriolis effect and wind currents that result from the friction caused by the Earth’s rotation. There are five major ocean-wide gyres — the North Atlantic, South Atlantic, North Pacific, South Pacific, and Indian Ocean gyres

Video Clip (2min)

Currents controlled by three factors –Global winds –Coriolis Effect –Continental Deflections

Coriolis Effect Link Coriolis Effect LinkLink –The apparent curving of moving objects due to the Earth’s rotation –Northern Hemisphere = clockwise –Southern Hemisphere = counter clockwise

Surface Current Link Link Horizontal, stream-like movements of water that occur at or near the surface of the ocean Horizontal, stream-like movements of water that occur at or near the surface of the ocean Can reach depths of several hundred meters Can reach depths of several hundred meters Largely responsible for the climate in many parts of the world Largely responsible for the climate in many parts of the world

Warm water surface currents Warm water surface currents –On the east coasts of continents –Bring warm water to colder regions Cold water surface currents Cold water surface currents –On the west coasts of continents –Bring cold water to warmer regions

Water Temperatures Affect on Surface Currents: Warm-water surface currents create a mild to warm climate (ex. British Isles and the Gulf Stream) Warm-water surface currents create a mild to warm climate (ex. British Isles and the Gulf Stream) Cold-water surface currents create a cooler climate (ex. California current cools of the Pacific coast all the way down to Mexico) Cold-water surface currents create a cooler climate (ex. California current cools of the Pacific coast all the way down to Mexico)

Warm water surface currents along the east coast

Cold water surface currents along the west coast.

Deep Currents Stream like movement of ocean water far below the surface Stream like movement of ocean water far below the surface Caused by changes in density Caused by changes in density –Change in temperature Decreasing the temperature of water increases density Decreasing the temperature of water increases density –Change in salinity Increasing the salinity of water increases density Increasing the salinity of water increases density

Upwelling Link Link The movement of deep, cold, nutrient rich water to the surface The movement of deep, cold, nutrient rich water to the surface Nutrients promote growth of fish and plants Nutrients promote growth of fish and plants Areas are important fishing grounds Areas are important fishing grounds

9min

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