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Definition
| An ocean basin is the middle part of the ocean floor. It is larger than continental margins. |
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Term
Continental Margins
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Definition
Continental margins consists of 5 main parts: continental shelf, continental slope, continental rise, abyssal plains, and submarine canyons.
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Continental Shelf
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Definition
| The continental shelf is a flat area that extends from the continent's shoreline the the ocean basin |
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Continental slope
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Definition
| The continental slope is a steep area that drops off rapidly to the ocean basin from the edge of the continental shelf. |
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Definition
| The continental rise is a more gentle slope between the continental slope and the abyssal plain. |
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| The abyssal plain is a broad, flat region in the middle of the ocean basin. It is surrounded by the rising outer edges of the continental margin. |
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Term
Turbidity currents
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Definition
Turbidity currents are underwater landslides from the continental slope. Also they can
move at a speed of 100 km/h and travel hundreds of kilometres down the continental slope and out along the ocean floor. Some turbidity currents are strong enough to scrape out large parts of the the continental shelf and slope. |
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Submarine canyons
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Definition
| Submarine canyons are deep gullies caused by turbidity currents. |
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Tectonic processes
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Definition
| Tectonic process is the movement of the plates and the way they interact, |
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Term
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Definition
| Tectonic plates are huge sections of Earth's crust. Tectonic plates float over a layer of molten rock called magma. There are two types of tectonic plates: continental and oceanic. Oceanic plates are denser than continental plates so they sink underneath when they collide. |
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Term
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Definition
| A mid-ocean ridge is an underwater chain of mountains. It can be as high as 3 km and more than 1000 km wide. It is caused when two pates are pushed apart and the underlying magma oozes up into the empty space. The largest mid-ocean-ridge is the mid-Atlantic ridge in the Atlantic ocean. |
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Definition
Subduction occurs when two plates collide and one of them sinks under the other. When that happens a trench is formed.
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Definition
| A trench is a long V-shaped grooved that marks the boundary between an oceanic plate and a continental plate. Trenches tend to develop near the edges of ocean basins. |
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Definition
| A seamount is an old inactive volcano that once developed near a mid-ocean ridge, but has been shifted away as the plates continue to move apart. |
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Term
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Definition
| A ocean current is a large amount of ocean water that moves, almost like a river, in a particular and unchanging direction. There are two main types of ocean currents: surface currents and deep water currents. |
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Term
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Definition
| A surface current is a type of ocean current. It extends to a depth of 200 m. The movement of surface currents is caused by wind action, Earth's surface, and the shape of the continents. |
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Term
Deep water currents
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Definition
| A deep water current is also a type of ocean current. It occurs deeper than 200 m. Its movement is caused by the temperature of the water and the salinity. |
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Term
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Definition
| Plankton are microscopic plants and animals that are an essential food source for all the other organisms in the ocean. |
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Term
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Definition
| A density current is the sinking and movement of dense water beneath surface water. This can create anything from excellent ocean fishing to bizarre weather. |
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Definition
| The Coriolis effect is the alternation of direction of winds and currents. A winds and currents move over Earth, their paths get redirected depending on what side of the equator they are on. To an observer standing on the surface of Earth in the northern hemisphere, the winds and currents would be deflected to the right (east). Standing on Earth's surface in the southern hemisphere, an observer would see the winds and currents being deflected to the left (west). |
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Term
Ocean surface (mixed layer)
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Definition
| The ocean surface is the warmest layer, where the Dun's energy heats the water. Surface currents keep the surface water mixing and temperature consistent. |
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Term
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Definition
| Thermocline can reach depths of 1 km below the ocean surface. The Sun's energy cannot reach this layer. This is the layer where temperature drops rapidly. |
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Definition
| The deep water layer lies below the thermocline. Temperatures at this level are only about 2oC above freezing. |
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Definition
Water with high salinity is dense than water with low salinity. The amount of salt in ocean water also contributes to the movement of density currents.
The salinity is higher near the equator and the poles. At the poles, this is because the temperature is very cold so the water freezes and salt is left behind. At the equator, this is because the rate of evaporation is high so water is evaporated and salt is left behind. |
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Term
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Definition
| Upwelling is the rising of water from the deep. This is causes by either cold water is warm enough to rise to the top or colder and denser water push the cold water up. Upwelling brings nutrient-rich waters to the surface, which feeds plankton, one of the main food sources for fish and other organisms in the ocean. Surface winds coming off land can also cause upwelling. As strong winds blow the surface water away from the shore, deep ocean water rises to take its place. |
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Definition
| Ocean waves are large ripple caused by wind passing over the surface of the water. The faster the wind blows, the longer it blows, and the larger the area it passes over, the bigger the waves will be. |
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Term
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Definition
| Swells are large, rolling waves that form in the open ocean. Most of them are only a few metres high, but some swells have been recorded at over 30 m high. Really strong winds, such as those created by hurricanes, can cause waves just as high to crash into areas a long the coast ocean. |
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Term
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Definition
| Breakers are swells when they reach shallow water. |
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Definition
| A tsunami is a huge ocean wave. They are caused by an earthquake beneath the ocean floor. |
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Definition
| Headlands are sections of the coastline that extend out into the ocean. They are composed of harder rock than the surrounding land, which is why they have not been eroded back as much |
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Term
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Definition
| Bays are indented areas in the coast line where the ocean reaches into the land. By the time ocean waves reach a bay, the waves are not travelling with the same amount of energy as when they hit the headlands. |
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Term
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Definition
| The tide is the daily cycle of rising and falling ocean water. Tides are caused by the gravitational attraction between earth and the Moon. There are two types of tides: neap tides and spring tides |
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Term
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Definition
| A spring tide is when the high tide is higher than usual and the low tide is lower than usual. This is caused when the Sun and the Moon line up and their gravitational pull combines. Spring tides happen twice a month. |
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Term
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Definition
| A neap tide is when the high tide is not as high and the low tides are not as low compared to the spring tides. Neap tides are caused when the Sun and the Moon are not in line and their gravitational pull on Earth is reduced. |
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Term
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Definition
| Heat capcityu is a measure of how long it takes for a material to heat up or cool down. |
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Definition
Weather is is the condition of the atmosphere at a specific time. Weather can be described in terms of temperature, wind speed and direction, air pressure, and moisture (precipitation).
Climate is all the features of the weather for a certain region averaged over a long time. |
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Term
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Definition
| Convection transfers heat by the flow of heated fluids. |
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Term
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Definition
| El Nino refers to the warm ocean waters off the coast of Ecuador and Peru that appear every year, about Christmas time. Usually, the currents last two to four weeks. The temperature of the ocean surface warms up in this area near the equator, extending in a current from the coast of South America all the way west to the middle of the Pacific Ocean. These warmer-than-normal waters lead to unusual weather pattens. El Nino has been responsible for changing patters of rainfall droughts and fires in Australia, Africa, and Central America. |
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Term
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Definition
| La Nina is a period when upwelling causes colder-than-normal waters to come to the surface off the coast of South America. La Nina often produces the opposite climatic effects to el Nino: locations where drought is brought by el Nino have wetter-than-normal periods during la Nina. |
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