Page 94 - Oceans

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glossary

Abyssal plain A flat area on the floor of the Continental slope The edge of the continental Food web The complex relationship between
deep ocean, beyond the continental shelf, at shelf that slopes down to the continental rise living things that feed on each other.
a depth of 13,000–20,000 ft (4,000–6,000 m). and ocean floor.
Fossil fuel A carbon compound that can
Algae Plantlike organisms that make sugar Convection The movement and circulation of be burned to release energy, such as coal,
using the energy of sunlight. Seaweeds are gases and liquids in response to heat. oil, or natural gas, made by the decomposition
large algae. of dead organisms over millions of years.
Convergent boundary A boundary between
Atmospheric pressure The pressure created by two plates of the Earth’s crust that are Fringing reef A coral reef that lies along a
the weight of air in the atmosphere, normally moving together, marked by earthquakes rocky shoreline (continent or island), and does
measured at sea level. and volcanoes. not enclose a well-developed shallow lagoon.
Atoll A ring-shaped island formed from a coral Corals Animals related to sea anemones that Geyser A jet of hot water and steam that
reef based on a sunken extinct volcano. often form reef-building colonies. regularly erupts from volcanically heated rocks.
Bacteria Microscopic organisms with a simple Crustacean An animal with a hard, shell-like Glacier A mass of ice that is flowing very slowly
single-celled structure. Some types can make external skeleton and paired, jointed legs, such downhill, usually through a deep valley.
food using energy that they get from sunlight as a crab or shrimp.
or chemical reactions. Global conveyor The linked system of currents
Current A flow of ocean water, driven by the that carries ocean water around the globe.
Barrier reef A coral reef that protects a shallow wind or by differences in water density caused
lagoon from the deep ocean. by temperature and salt content. Granite A crystalline, hard rock that is one of
the main rocks found in continental crust.
Basalt A dark, heavy volcanic rock that forms Cyclone A weather system marked by clouds,
oceanic crust and erupts as molten lava from rain, and strong winds, caused by air swirling Greenhouse effect The warming effect caused
midocean ridges and hotspot volcanoes. into a region of rising warm, moist air. by the way atmospheric gases such as carbon
dioxide, methane, and water vapor absorb some
Bedrock The solid rock that lies beneath more Dark zone The deep region of the ocean where of the heat radiated from Earth, and stop it
recent, softer sediments. there is no light. from escaping into space.
Biogenic ooze A soft sediment formed from Decompose To rot. Gyre A large-scale circular pattern of ocean
the skeletal remains of microorganisms currents, rotating clockwise north of the equator,
such as plankton. Delta An accumulation of sand and silt laid and counterclockwise south of the equator.
down at the mouth of a river, usually with
Black smoker A hot spring or hydrothermal vent several distributary channels flowing over it. Headland A narrow area of coastal land
on the ocean floor, usually at a midocean ridge, projecting between two bays.
that erupts dark, cloudy, mineral-rich water. Density The compactness of a substance.
If the substance is squeezed together, it Hotspot An unusually hot part of the Earth’s
Bycatch Animals such as the wrong type of becomes more dense. thick mantle, which makes volcanoes erupt
fish, marine mammals, and seabirds that are through the crust above.
accidently caught when fishing. Depression An area of low atmospheric pressure
in which warm air converges and rises. Also Hydrothermal vent A hot spring in the ocean
Carbohydrates Compounds of carbon, known as a cyclone. floor, normally on a spreading rift. Also known
hydrogen, and oxygen that store energy, as a black smoker.
made by some living things and used as Divergent boundary A boundary between two
food. Sugars are simple carbohydrates. plates of the Earth’s crust that are moving apart. Intertidal Refers to the area of the shore that
is covered and uncovered by the tides.
Carbon dioxide A gas that forms a very small DNA (Deoxyribonucleic acid) The complex protein-
percentage of the atmosphere. Living things like substance that contains the instructions Invertebrate An animal that does not have an
such as plants and phytoplankton use it to needed to direct the growth of a living thing. internal skeleton based on spinal bones.
make food, and it is also a greenhouse gas. Downwelling zone A sea area where water Island arc A line of islands marking a boundary
Chemosynthesis Using the energy of chemical is sinking. between two plates of the Earth’s crust, created
reactions to make food (carbohydrates) from Echo-sounding Using sound pulses (sonar) to by volcanic activity as one plate plunges
carbon dioxide and water. measure water depth, or detect schools of fish. beneath the other and is destroyed.
Chlorophyll A substance that absorbs the Ekman spiral The way moving water swerves Krill Oceanic shrimp that form large swarms in
energy of sunlight, used by some living things increasingly to the right or left with depth, the Southern Ocean, and are the main food of
to make food in the process of photosynthesis. most Antarctic animals.
so it moves in a different direction from the
Coccolith The skeleton of a microscopic marine surface water. Lagoon An area of shallow water that has been
organism called a coccolithophore, which in El Niño A change in the ocean currents of the cut off from the sea.
large numbers forms limestone or chalk rock.
equatorial Pacific, when warm surface water Lava Molten rock that erupts from volcanoes or
Condense To turn from a gas to a liquid. moves east to suppress the normal flow of volcanic fissures.
colder water. This affects the oceanic food
Continental crust A thick slab of relatively light supply and weather. Longline A very long fishing line equipped with
rock that "floats" on the Earth’s mantle. thousands of baited hooks.
Erosion Wearing away, usually by natural forces
Continental rise The slope that links the edge of such as waves on the shore. Longshore drift The movement of beach
the continental slope with the deep ocean floor. material along the shore by waves.
Estuary A river mouth.
Continental shelf The submerged fringe of a Magma Molten rock that has not erupted and
continent, which lies beneath a coastal sea. Evaporate To turn from a liquid to a gas. is still contained within the Earth’s crust.