IB definitions: Oceans

kirsten w
Flashcards by kirsten w, updated more than 1 year ago
kirsten w
Created by kirsten w over 3 years ago


Geography (Oceans) Flashcards on IB definitions: Oceans, created by kirsten w on 01/11/2017.

Resource summary

Question Answer
Oceans Bodies of water that surround continents which usually have high concentrations of salt
Sea Bodies of water that are surrounded by land, which usually consist of salt water
Convection currents Cause plate movement below the earth's crust, and form oceanic and continental features
Divergent plate boundary Boundary where tectonic plates spread apart, and magma rises and then is cooled
Convergent plate boundary Boundary where plates move closer together, and crust is destroyed in this collision
Transform plate boundary Boundary where tectonic plates slide past each other but no new plate material is formed or destroyed
Hot Spot A very hot area in the mantle creates a hot spot where volcanoes can form in the middle of tectonic plates
Guyot A seamount that has a flat top due to either erosion, or a previously sunken volcanic island
Abyssal Plain The largest part of the ocean floor that consist of a fairly deep level plain. Starts at the end of a continental slope, and is featureless except for seamounts, ridges, guyots and volcanic islands.
Continental shelf A relatively flat and shallow area of seabed that stretches from the coast to the edge of the shelf where it suddenly drops to the ocean floor.
Continental slope The edge of a continental shelf where the ocean floor drops down steeply to an abyssal plain
Submarine canyon The result of 'landslides' found along the continental slope. Deep divots in the slope.
Abyssal hill A small hill that rises from the abyssal plain, no more than a few hundred meters
Seamount A volcano that has not reached all the way to the surface of the water to be considered a volcanic island
Oceanic trench A deep depression that is found along the edges of the ocean floor. Usually found where two plates collide and one is forced under the mantle
Thermocline The temperature in the top 500 m of water decreases at a steady rate, however after that temperatures take a sharp change.
Salinity The salt content of the ocean water, measured in ppm
Thermohaline circulation The oceanic conveyor belt that includes both subsurface currents and surface currents
La Niña A phenomenon caused by very strong trade winds that cause warm water to be pushed further west
El Niño A phenomenon caused by weak trade winds that cause warm water to be collected in the east
Overfishing To continuously catch more fish than the system can naturally produce
Biotic Living factors in an ecosystem
Abiotic Nonliving factors in an ecosystem
Eutrophication A process by which nutrients, particularly phosphorous and nitrogen, become highly concentrated in a body of water, leading to an increased growth of organisms such as algae or cyanobacteria
Red Tides A red, orange or brown colouration of the water caused by a bloom or population explosion of algae; many cause serious environmental harm and threaten the health of humans and animals
Currents Mass movements of surface water produced by prevailing winds blowing over the oceans
Exclusive Economic Zone Areas extending 200 nautical miles (370 km) from shore over which countries have sovereign rights for resource exploration
Territorial waters Area that extends from 0 to 12 nautical miles from a countries coastline where the same law on apply
Polyp A strand of many amino acids linked together by peptide bonds from which coral reefs are formed. It is an organism.
Fringing reef A coral reef that develops as a narrow band close to a shore
Barrier reef A coral reef surrounding an island or lying parallel to the shore of a continent, separated from land by a deep lagoon. Coral debris islands may form along the reef.
Atoll A ring shaped reef composed largely of coral. These features are quite common in the tropical waters of the Pacific Ocean
Mangroves Salt-tolerant forests of trees that grow along tropical coastlines in the interdital zone.
Drift nets Transparent nets that drift overnight catching anything within a 2 to 90 km radius
Bottom drag nets Turn the ocean floor into a waste land by dragging them along the sea floor
Dynamite fishing Coral is blown up to stun the fish along them and causing them to float on top of the water.
Cyanide fishing Cyanide is emptied into the ocean, poured on top of a reef and the fish that die will float at the surface
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