Circulation (CURRENTS)
Circulation of ocean water has profound effects on organisms living in the open ocean and coastal embayments. Within bays and estuaries, tidal currents circulate and mix ocean and bay water transporting larva from offshore to bays and nutrients from bays to ocean.
Waves break along the shore at angles and the current flow parallel to the coast. This is the longshore current or littoral drift which is the movement of water within the breaker zone and strictly from breaking waves
Currents in the open oceans (Graphic)
Surface and wind driven currents carry plankton. The thermohaline/deep sea circulation brings O2 to abyss and disperses eggs and young of deep sea creatures and transports heat.
The suns irregular heating patterns of the atmosphere creates regular wind patterns around the world. Frictional drag of prevailing wind along the ocean surface waters causes them to move. (friction decreases with depth)
Coriolis effect-wind and water are deflected to the right in the northern hemisphere (left in Southern Hemisphere) due to the earths rotation and causes water to rotate slowly in circular rivers or gyres.
Ekman spiral is formed when wind driving surface currents and the coriolis effect creates additional deflection of water 100-200m below. Each succeeding layer is deflected further to the right. In some cases this spiral is responsible for a phenomenon known as UPWELLING.
Movements of surface water away from the shore enables cold, dense bottom water to rise and mix with warmer surface water (UPWELLING). it carries significant amounts of dissolved minerals to the oceans upper sunlit limit supplying fertilizer to plants near the surface...grow food for the fish. When upwelling stops, the numerous fish disappear..El nino--- see 2003 Florida East Coast Upwelling Event Information
Deep sea circulation is driven by temperature and density deficiencies within the ocean. these are called thermohaline currents. As the water cools it becomes more saline..some water form ice crystals so salt is left behind. Water is more salty, higher density, sinks to a denser layer, pushes out polar water toward equator, horizontally moving deep water masses are deflected by the coriolis bending. These currents help deliver dissolved O2 to the bottom communities where there is no circulation. Bottom water that is devoid of O2 is called anoxic/deoxygenated water.
Major ocean currents....show..explain where its warm and cold
5,3 UPWELLING Questions
1. What is upwelling?
2. What does it do to the ocean and how does this effect productivity?
3. What effect causes this deflection of the water currents?
4. Where are major upwelling areas on earth?
5. What causes downwelling?
6. How does this effect deep waters?
7. How is
productivity of
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