Presentation on theme: "Ocean Currents Earth and Space Science. Ocean waves carry matter and energy Ocean waves carry matter and energy This thermal energy can be transferred."— Presentation transcript:
Ocean waves carry matter and energy Ocean waves carry matter and energy This thermal energy can be transferred to the air, and to the land. This thermal energy can be transferred to the air, and to the land. There are multiple layers in the ocean There are multiple layers in the ocean There are multiple densities of water in the ocean There are multiple densities of water in the ocean The ocean’s salinity is not uniform The ocean’s salinity is not uniform Seawater Temperature, Salinity and Density
Currents Water in oceans can sink, rise, and flow horizontally
Cold water is more dense and sinks Warm water is less dense and stays at the surface B. Density is determined by 2 factors
2. Salinity Concentration of dissolved salts in the seawater Expressed as parts per thousand Approximately 35 parts per thousand (35 g salts per 1000 g water) Higher salinity = higher density B. Density is determined by 2 factors
Surface water can change in density by changing salinity due to excess rain or increased evaporation or where rivers enter the ocean B. Density is determined by 2 factors
II. Water Masses The ocean is a single body of water but is not the same everywhere Temperature and salinity vary from place to place Water Mass – a large region of water within the ocean that is about the same temperature and salinity
B. Gyres help transport energy and matter from low latitudes to the higher latitudes.
C. Caused by blowing winds near the Equator 1. Tradewinds/Easterlies – at low latitudes/tropics Blow East to West
2. Prevailing Westerlies – in mid-latitudes Blow West to East
D. Eckman Drift – horizontal movement of water resulting from the balance of the Coriolis effect and wind stress
1. Causes water to move at an angle to the right of the general wind direction (90 o ) 2. Causes a “mound of water” which balances out the Eckman Drift
E. Upwelling Strong upward movement of water from the deep to the surface
E. Upwelling 1. As water moves away from the coastline due to the Eckman Drift, more water flows up to replace it from deeper in the ocean. 2. The upward movement brings nutrient rich deep water to shallow areas for animals and plants to use
3. Nutrients come from the “rain” of dead organisms from the warmer surface layer 4. Deep circulation moves the nutrients around, and then upwelling generally moves the nutrients to the eastern sides of ocean basins. 5. Most fisheries are supported by this upwelling of nutrients.
F. Downwelling Downward motion of surface water to the deep ocean