These currents move water masses through the deep ocean—taking nutrients, oxygen, and heat with them. Dangerous currents occur in many ocean and Great Lakes beach areas. Dangerous currents are dangerous because they can pull swimmers away from shore. Each year there are many current-related deaths and rescues. One major example of an ocean current is the Gulf Stream in the Atlantic Ocean.
Ocean currents can be found on the water surface and deeper down. Currents on the surface often depend on wind. They travel clockwise in the northern hemisphere. Begin typing your search term above and press enter to search.
Press ESC to cancel. It is this movement that creates circulation patterns known as convection currents in the atmosphere, in water, and in the mantle of Earth. In the atmosphere, as air warms it rises, allowing cooler air to flow in underneath.
Along with the turning of the Earth, this movement of air creates winds. Winds, in turn, create surface waves on the ocean. Convection also plays a role in the movement of deep ocean waters and contributes to oceanic currents. Inside Earth, the convection of mantle material is thought to cause the movement of the overriding crustal plates, resulting in events such as earthquakes and volcanic eruptions.
Part A Density and Convection Per student or pair of students: three 8 oz. Part B Convection Current Class Demonstration Small aquarium, water immersion heater, blue ice cubes, red food color, medicine dropper, small paper cup, tape. Part A Density and Convection small groups Discuss or review the concept of density relative to temperature. Fill each plastic cup with 6 ounces ml of water. Allow the water to stand about 5 minutes. Fill a small container with very cold water.
Add a drop of blue food color. The air rises toward the ceiling, pulling cooler air down from the ceiling into the radiator to be heated. This process repeats until the air in the room is evenly heated.
This process distributes heat and soluble nutrients around the world. As it rises, it cools and becomes less dense than the air around it, spreading out and descending toward the equator again. Atmospheric convection currents are also what keep clouds aloft. Geologists believe the molten rock deep within the earth circulates by convection currents. These constantly circulating cells of hotter and cooler molten rock are thought to help heat the surface. Why is the water temperature cooler in some places?
Water cools as it moves from the equator to the poles via surface currents. Cooler water is more dense so it begins to sink. As a result, the surface currents and the deep currents are linked. Wind causes surface currents to transport water around the oceans, while density differences cause deep currents to return that water back around the globe Figure As you have seen, water that has greater density usually sinks to the bottom.
However, in the right conditions, this process can be reversed. Denser water from the deep ocean can come up to the surface in an upwelling Figure Generally, an upwelling occurs along the coast when wind blows water strongly away from the shore.
As the surface water is blown away from the shore, colder water from below comes up to take its place. This is an important process in places like California, South America, South Africa, and the Arabian Sea because the nutrients brought up from the deep ocean water support the growth of plankton which, in turn, supports other members in the ecosystem. Upwelling also takes place along the equator between the North and South Equatorial Currents. Skip to main content. The Ocean.
Search for:. Ocean Currents Ocean water is constantly in motion Figure The direction that they spin depend on the hemisphere that they are in.
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