2Factors Influencing Surface Ocean Currents The ocean's surface currents follow the general pattern of the world's major wind beltsGyres:slowly moving loops of watercentered in the subtropics of each ocean basinthe positions of the continents and the Coriolis Effect affect water movement within gyres
3Gyres:Coriolis Effect:An apparent force due to the Earth's rotation. Causes moving objects to be deflected to the right in the Northern Hemisphere and to the left in the Southern hemisphere. Coriolis force does not exist on the equator. This force is responsible for the direction of flow in meteorological phenomena like mid-latitude cyclones, hurricanes, and anticyclones.
4Gyres:Coriolis Effect:causes subtropical gyres to move clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemispherefour main currents comprise each subtropical gyrefive main subtropical gyres:Indian Ocean gyreNorth Atlantic gyreNorth Pacific gyreSouth Atlantic gyreSouth Pacific gyre
5Deep-Ocean Circulation Also referred to as thermohalineIt is caused by density variationsDensity variations are caused by differences in temperature and salinityMost water involved in deep-ocean circulation begins in high latitudes at the surfaceSurface water becomes cold and salinity increases as sea ice formsWhen water becomes dense enough, it sinks forming currentsOnce it sinks, it stays the same temperature and salinity remain the same while in the deep-oceanAntarctic water-surface conditions create the highest density water in the worldThe water sinks to the seafloorIt moves throughout ocean basins in sluggish currentsDeep waters will not resurface for yearsOcean-circulation is similar to a conveyer belt that travels from the Atlantic through the Indian to the Pacific
7Importance of Surface Ocean Currents Surface ocean currents have important effects on climate.Currents moved from lower-latitude regions into higher latitudes transfer heat from warmer to cooler areas on earth.Warm ocean currents which are felt in the middle latitudes in winter, the influence of cold currents is most pronounced in the tropics or during the summer months in the middle latitudes.As the cold currents travel equatorward, they tend to moderate the warm temperature of adjacent land areas.Cold currents are also associated with greater fog frequency and drought.Ocean currents also play a major role in maintaining Earth's heat balance.they transfer heat from tropics, where there is excess amounts of heat, to the polar regions.Ocean currents also play an important role in navigation.
10Upwelling Upwelling the rising of colder water from deep layers wind-induced movement that brings cold, nutrient water to the surfaceIt also affects the movement of animalsvertical water movementsa common type of upwelling is coastal upwellingbrings greater concentrations of dissolved nutrients, such as nitrates and phosphates, to the ocean surface
12Coastal upwelling Coastal Upwelling most characteristic along the west coasts of continents (e.g; along California and western South America)occurs when wind blows toward the equatorwhen combined with the Coriolis effect, water moves from the shoreslow upward movement of water from depths of 50 to 300 meters ( 165 to 1000 feet) brings water that is cooler than the original surface water and results in lower surface water temperatures near the shore
14Various Components of the Coastal Zone ShoreThe area extending between the lowest tide level and the highest elevation on land that is affected by storm waves.The coast extends inland from the shore as far as ocean-related features can be found.The shore is divided into two parts.ForeshoreSeaward of foreshore are the nearshore and offshore zones.BackshoreLandward of the high-tide shorelineUsually dry, being affected by waves only during storms.NearshoreLies between the low-tide shoreline and the line where waves break at low tides.Offshore ZoneSeaward of the offshore zone.
15Various Components of the Coastal Zone ShoreBeachAn accumulation of sediment found along the landward margin of the ocean or a lake.May extend for tens/hundreds of km. along straight coasts.Formation may be confined to the quiet waters of bays.BermsRelatively flat platforms often composed of sand that are adjacent to coastal dunes or cliffs and marked by a change in slope at the seaward edge.BeachfaceWet sloping surface that extends from the berm to the shoreline.