Read each term where it’s used
In Augment’s notes, a marked term shows its definition when you hover or tap it, and each page ends with the terms it introduces.
In Augment’s notes, a marked term shows its definition when you hover or tap it, and each page ends with the terms it introduces.
153 terms from Oceans and coastal margins, each defined in a sentence or two, with the part of the syllabus where you first meet it.
A natural resource that comes from non-living parts of the environment, such as minerals, oil, gas, sand or water, rather than from living organisms.
The farming of fish, shellfish, seaweed and other aquatic organisms in ponds, tanks, cages or other enclosures.
An island created by people by piling sand, rock or other material onto a reef or seabed, or by building a platform; under UNCLOS it generates no territorial sea or EEZ.
The Atlantic part of the global ocean conveyor belt, in which warm surface water flows north, cools and sinks in the North Atlantic, and returns south as cold deep water.
The return flow of water down a beach under gravity after the swash, carrying sediment back towards the sea at right angles to the shoreline.
A ridge of sand or shingle that extends across a bay, joining two headlands and enclosing a lagoon behind it.
The line, normally the low-water line along the coast, from which a state's territorial sea, EEZ and other maritime zones are measured.
An accumulation of sand or shingle on the shore between the low water mark and the limit of storm waves, shaped by the balance between swash and backwash.
The artificial addition of sand or shingle to a beach, usually dredged from offshore, to make it higher and wider so that it absorbs more wave energy.
The transfer of carbon from the surface ocean to the deep ocean and sea floor by organisms, as phytoplankton take up CO₂ and dead organisms and faecal pellets sink.
A natural resource obtained from living organisms, such as fish, shellfish, marine mammals or seaweed.
A hollow in a sand dune scooped out by wind erosion where the protective vegetation cover has been broken by trampling, grazing or storms.
Carbon captured and stored by coastal and marine ecosystems, especially mangroves, saltmarshes and seagrass meadows, mostly in their waterlogged soils.
Fish and other marine animals, such as dolphins, turtles and seabirds, caught unintentionally while fishing for a target species.
The process by which marine organisms such as corals, molluscs and some plankton build shells and skeletons of calcium carbonate from dissolved calcium and carbonate ions.
The harvesting of wild fish and other aquatic animals from the sea, rivers and lakes, as opposed to farming them.
The use of measures such as regrading, drainage, toe protection, rock bolts and vegetation to reduce erosion and mass movement on a cliff.
The planning and use of strategies to reduce coastal erosion and flood risk and to balance the competing human and environmental uses of a coastline.
The division of a coastline and its waters into zones in which particular uses, such as ports, tourism or conservation, are permitted or banned.
An ocean current colder than the surrounding water and air, usually flowing from high latitudes towards the Equator on the eastern side of an ocean basin.
The principle that certain areas and their resources, such as the deep seabed beyond national jurisdiction, belong to all humanity and must be managed for the benefit of all.
A coastline where bands of rock of different resistance run parallel to the shore, so that a resistant outer band protects weaker rock behind it.
A grid that compares each pair of land uses or activities in an area and shows whether they are compatible, in conflict, or compatible only under certain conditions.
A low, long and gentle wave, breaking about 6–8 times a minute, whose strong swash and weak backwash move sediment up the beach and build it up.
The belt of sea from 12 to 24 nautical miles from a state's baseline, in which the state may enforce its customs, tax, immigration and health laws.
In law, the seabed and subsoil beyond a state's territorial sea to 200 nautical miles, or to the edge of the continental margin up to 350 nautical miles, over whose resources the state has rights.
A structure built over thousands of years from the calcium carbonate skeletons of reef-building corals, in warm, shallow, clear tropical seas, supporting very high biodiversity.
The apparent deflection of moving air and water caused by the Earth’s rotation, to the right in the northern hemisphere and to the left in the southern hemisphere; zero at the Equator.
The extraction of mineral deposits such as polymetallic nodules, seafloor massive sulphides and cobalt-rich crusts from the deep-ocean floor.
A high, steep and frequent wave, breaking about 10–14 times a minute, whose strong backwash removes sediment from the beach and carries it offshore.
A coastline where bands of rock of different resistance run at right angles to the shore, so that weak rock is eroded into bays and resistant rock forms headlands.
The rebuilding or stabilising of sand dunes by planting marram grass, fencing, thatching and controlling access, so that they store sand and protect the land behind.
A damp hollow between dune ridges where the surface lies close to the water table, supporting moisture-loving plants such as reeds, rushes and willows.
The warm phase of ENSO, in which the trade winds weaken, warm water spreads east across the equatorial Pacific, upwelling off South America weakens and rainfall shifts east.
The irregular cycle of coupled changes in sea surface temperature and air pressure across the tropical Pacific, with a warm phase (El Niño), a cold phase (La Niña) and a neutral state.
A small, young and unstable sand dune at the top of a beach, formed where sand collects around obstacles and is colonised by salt-tolerant pioneer plants such as sea couch grass.
A coastline where the land has risen relative to the sea, leaving former shoreline landforms such as raised beaches and relict cliffs above the reach of waves.
A worldwide change in sea level caused by a change in the volume of ocean water, such as water stored in ice sheets during glacial periods or melting and thermal expansion today.
The area of sea up to 200 nautical miles from a state's baseline in which that state has sole rights to the natural resources of the water and seabed, while other states keep freedom of navigation.
The calm, often cloud-free centre of a tropical cyclone, typically 20–50 km across, where air sinks and surface pressure is lowest.
The ring of towering thunderclouds around the eye of a tropical cyclone, where air rises fastest and the strongest winds and heaviest rain occur.
The distance of open water over which the wind blows to generate waves; the longer the fetch, the larger and more powerful the waves can become.
A population of one fish species in a particular area that is managed as a single unit.
A limit on the amount of fish that a country, fleet, vessel or business may catch, usually a share of a total allowable catch.
A long, narrow, deep and steep-sided coastal inlet formed when a glacial trough was flooded by the sea, often with a shallow rock threshold at its mouth.
A young, mobile sand dune behind the embryo dunes, dominated by marram grass, with bare sand between the plants giving it a yellow colour; also called a yellow dune.
A wire-mesh cage filled with stones, stacked to form a wall or slope that absorbs wave energy; a cheap but short-lived coastal defence.
An area of an ocean gyre where floating plastic and other debris carried by surface currents accumulates in high concentrations.
The slow rise of the Earth’s crust after the melting of an ice sheet that had pressed it down, continuing for thousands of years.
An area or resource outside the jurisdiction of any single state, such as the high seas, the atmosphere or Antarctica, that is shared by all.
The global pattern of the thermohaline circulation, in which dense water sinks in the North Atlantic and around Antarctica, flows through the deep ocean and returns as surface currents in about 1,000 years.
A more stable sand dune further inland, darkened by humus and colonised by mosses, lichens and other plants, with more acidic soil than younger dunes.
A barrier built at right angles to the shoreline to trap sediment carried by longshore drift and so build up a wider beach.
A warm, fast ocean current flowing from the Gulf of Mexico along North America and across the Atlantic as the North Atlantic Drift, carrying heat towards north-west Europe.
A large, roughly circular system of surface ocean currents in an ocean basin, driven by prevailing winds and the Coriolis effect; clockwise in the northern hemisphere, anticlockwise in the southern.
The use of artificial structures such as sea walls, groynes and rock armour to control natural coastal processes and protect the land behind them.
The parts of the ocean beyond any state's exclusive economic zone, open to all states and governed by international law.
A coastal management policy of keeping the shoreline in its present position by maintaining existing defences or building new ones.
A tropical cyclone that forms in the North Atlantic, Caribbean Sea, Gulf of Mexico or north-east Pacific, with sustained winds of at least 119 km/h.
An opening in the seabed, usually on a mid-ocean ridge, from which water heated by magma flows out, depositing metal-rich sulphide minerals and supporting unique ecosystems.
Fishing that breaks national or international rules, is not reported to the authorities, or takes place where no rules apply, for example by stateless vessels.
A share of a total allowable catch held by an individual or company, which can be bought, sold or leased.
The right of foreign ships to sail through a state's territorial sea without stopping, provided they do not threaten its peace, order or security.
An approach that plans and manages all the uses of a coastal area together, across land and sea and across sectors and levels of government, with the participation of all its stakeholders.
A change in the level of the land relative to the sea, caused by the crust rising or sinking, for example under the weight of an ice sheet or after it melts.
The cold phase of ENSO, an intensified form of normal conditions, in which stronger trade winds increase upwelling off South America and rainfall over the western Pacific.
The creation of new land from the sea, a lake or a wetland by draining it or filling it with sand, rock or other material.
The energy absorbed when water evaporates and released when water vapour condenses, without a change in temperature; the main energy source of tropical cyclones.
The physical and chemical characteristics of a rock, such as mineral composition, hardness, grain size and permeability, which affect its resistance to erosion and weathering.
The international treaty of 1972 controlling the deliberate dumping of wastes at sea from ships, aircraft and platforms; since 1993 it has banned dumping radioactive waste.
The movement of sediment along a coast by waves approaching at an angle, as swash carries material diagonally up the beach and backwash returns it straight down; also called littoral drift.
A salt-tolerant tree or shrub that grows in the intertidal zone of sheltered tropical and subtropical coasts; mangrove swamps are forests of these trees.
A period of days to months in which ocean temperatures in a region are unusually high for the time of year, commonly above the 90th percentile for at least five days.
Plastic waste in the sea, from large items such as bottles, bags and fishing nets to tiny fragments known as microplastics.
An area of sea or coast in which human activities such as fishing, mining or development are restricted by law to protect its ecosystems and resources.
A disagreement between states over sovereignty of islands or other features, the boundaries of maritime zones, or rights to use the sea and its resources.
The International Convention for the Prevention of Pollution from Ships (1973, modified 1978), which regulates discharges of oil, chemicals, sewage, garbage and air pollutants from ships.
A coarse grass adapted to coastal dunes, with rolled leaves that reduce water loss, deep roots and rapid growth when buried by sand, which binds and builds foredunes.
The largest catch that can be taken from a fish stock year after year without reducing its size, reached when the stock is kept at a medium level.
A piece of plastic smaller than 5 mm, either manufactured at that size, such as microbeads, or formed when larger plastic breaks down.
A unit of distance used at sea and in maritime law, equal to 1.852 km and based on one minute of latitude.
A tide with the smallest tidal range, occurring twice a month when the Sun and Moon are at right angles to each other relative to the Earth.
A coastal management policy under which no investment is made in building or maintaining defences, so that natural processes are allowed to shape the coast.
An area of sea, usually within a marine protected area, in which all fishing and collecting of marine life is banned.
A continuous, directed movement of seawater, driven at the surface mainly by prevailing winds and at depth by differences in water density.
The introduction by people of substances, objects or energy into the sea that harm living resources, human health or legitimate uses of the sea.
NOAA’s index of ENSO: the three-month running mean of sea surface temperature anomalies in the Niño 3.4 region; +0.5 °C or more indicates El Niño and −0.5 °C or less La Niña.
A barrier of rock or concrete built in the sea parallel to the coast, so that waves break and lose energy before they reach the shore.
Petroleum and natural gas extracted from rocks beneath the seabed using fixed platforms, floating production units or drill ships.
The release of liquid petroleum into the environment, especially the sea, from tankers, pipelines, offshore platforms or wells.
Catching fish from a stock faster than it can replace itself through reproduction and growth, so that the stock declines.
An arrangement in which those who benefit from an ecosystem pay the people who manage it to keep it intact, for example through blue carbon credits.
Microscopic plant-like organisms, mainly algae and cyanobacteria, that drift in the sunlit surface ocean and photosynthesise, forming the base of most marine food webs.
A lump of minerals a few centimetres across, rich in manganese, nickel, cobalt and copper, that forms very slowly on the deep-ocean floor.
A plant succession that develops on bare sand, as on coastal dunes, from salt-tolerant pioneer plants near the beach to heath or woodland inland.
Material that emits ionising radiation, produced by nuclear power, fuel reprocessing, weapons and medicine, which must be isolated from people and the environment.
A former beach, now above present high tide level, left behind when the land rose relative to the sea; usually a flat terrace backed by a relict cliff.
An increase in the maximum sustained wind speed of a tropical cyclone of at least 55 km/h (30 knots) within 24 hours.
Active intervention to help a damaged coral reef recover, for example by growing coral fragments in nurseries and transplanting them or stabilising rubble so corals can settle.
The change in the level of the sea compared with the land at a particular place, the combined result of eustatic and isostatic change.
A former sea cliff no longer reached by the waves, because the land has risen or the coast has advanced, and now shaped by subaerial processes.
A sloping structure of concrete, stone, timber or rock placed at the foot of a cliff or back of a beach, on which waves run up and lose energy.
A drowned river valley formed when a rise in sea level flooded an unglaciated valley, becoming wider and deeper towards the sea.
Large boulders piled at the foot of a cliff or sea wall so that waves break on them and lose energy before reaching the land.
The Saffir–Simpson Hurricane Wind Scale, which classifies hurricanes into categories 1 to 5 by maximum sustained wind speed, from 119–153 km/h (category 1) to 252 km/h or more (category 5).
The concentration of dissolved salts in seawater, averaging about 35 g per kg; it rises with evaporation and sea-ice formation and falls with inputs of fresh water.
An area of mudflats colonised by salt-tolerant plants in a sheltered, low-energy intertidal zone, such as behind a spit or in an estuary, where fine sediment settles.
A mound or ridge of sand deposited by the wind; coastal dunes form behind wide beaches where onshore winds carry dry sand inland and vegetation traps it.
The temperature of the top few metres of the ocean, measured by ships, buoys and satellites; departures from average (anomalies) are used to monitor ENSO and marine heatwaves.
A wall of concrete, stone or steel built along the coast to stop waves eroding or flooding the land behind it; a recurved sea wall has a curved top that deflects waves seaward.
A length of coastline, usually bounded by headlands or estuaries, within which sediment moves in a largely closed system of sources, transfers and sinks.
A line a set distance inland from the shoreline, seaward of which new building is not permitted, so that development is kept out of areas likely to erode or flood.
A long-term plan for a stretch of coast, usually based on a sediment cell, that sets a management policy for each section of shoreline over the next 100 years.
Coastal management that works with natural processes by adding or restoring beaches, dunes, saltmarshes or mangroves that absorb wave energy, rather than building artificial structures.
The physical transfer of carbon dioxide from the atmosphere to the deep ocean, as it dissolves in cold high-latitude surface water that then sinks with the thermohaline circulation.
An index of the difference in sea-level air pressure between Tahiti and Darwin; sustained negative values indicate El Niño and sustained positive values indicate La Niña.
The supreme and independent authority of a state over its territory, including its land, internal waters, territorial sea and the airspace above them.
A long, narrow ridge of sand or shingle joined to the land at one end and extending across a bay or estuary, built by longshore drift where the coast changes direction.
A tide with the largest tidal range, occurring twice a month when the Sun, Moon and Earth are in line and their gravitational pulls combine.
An isolated pillar of rock standing in the sea off a headland, left when the roof of an arch collapses.
A sudden and severe fall in a fish population, usually to a small fraction of its former size, from which it may recover only slowly or not at all.
An abnormal rise in sea level generated by a storm, above the predicted tide, caused mainly by onshore winds piling water against the coast and partly by low pressure lifting the sea.
A movable barrier across an estuary or channel that is closed when a storm surge or exceptionally high tide is forecast, to stop the sea flooding the land upstream.
The importance of a place or area to a state's security, economy or power, for example because it controls a trade route, a choke point or resources.
Processes that act on the land surface above the reach of waves, mainly weathering and mass movement, which weaken cliffs and move material down them.
A coastline where the sea has risen relative to the land, drowning former valleys to form features such as rias and fjords.
The gradual change in the plant communities of an area over time, as each stage alters conditions so that new species can establish, ending in a stable climax community.
The rush of water up a beach after a wave breaks, carrying sediment in the direction in which the wave is travelling.
A link between a climate anomaly in one part of the world and changes in weather or climate in distant regions, transmitted through the atmospheric circulation.
The belt of sea up to 12 nautical miles from a state's baseline, over which the state has sovereignty, subject to the right of innocent passage of foreign ships.
The layer of the ocean, between the warm mixed surface layer and the cold deep water, in which temperature falls rapidly with depth.
The large-scale circulation of the oceans driven by differences in seawater density, which depend on temperature and salinity; cold, salty water sinks at high latitudes.
The vertical difference in height between high tide and low tide at a place, from under 2 m on microtidal coasts to over 4 m on macrotidal coasts.
The periodic rise and fall of sea level, usually twice a day, caused by the gravitational pull of the Moon and the Sun on the Earth’s oceans.
A ridge of sand or shingle, formed by deposition, that joins an island to the mainland or to another island.
The maximum quantity of a fish stock that may be caught in a period, usually a year, set to keep the stock at a sustainable level.
The steady easterly winds blowing from the subtropical high-pressure belts towards the Equator, from the north-east in the northern hemisphere and the south-east in the southern hemisphere.
The tendency for a shared resource open to all to be over-used and degraded, because each user gains the full benefit of using more while the costs are shared by everyone.
An intense, rotating low-pressure system over warm tropical oceans, with thunderstorms around a central eye and sustained winds of at least 119 km/h; called a hurricane, typhoon or cyclone by basin.
A tropical cyclone that forms in the north-west Pacific Ocean, west of the date line, with sustained winds of at least 119 km/h.
The international treaty of 1982, in force since 1994, that defines the maritime zones of coastal states, their rights and duties in each, and the rules for the high seas and deep seabed.
The rise of cold, nutrient-rich water from below the thermocline to the ocean surface, usually where winds move surface water away from a coast.
The east–west loop of air over the equatorial Pacific, rising over the warm west, flowing east aloft, sinking over the cool east and returning west as the trade winds.
An ocean current warmer than the surrounding water and air, usually flowing from low latitudes towards the poles on the western side of an ocean basin.
The bending of wave crests as they slow in shallow water near the coast, which concentrates wave energy on headlands and spreads it out in bays.
An indentation cut into the base of a cliff between high and low tide by hydraulic action and abrasion.
A gently sloping rocky surface at the base of a cliff, exposed at low tide, left behind as the cliff retreats through erosion and collapse.
The breakdown or decay of rock in its original place by physical, chemical or biological processes, without the rock being moved.
The pause on all commercial whaling agreed by the International Whaling Commission in 1982, which took effect in 1986.
The change in wind speed or direction with height; strong vertical wind shear tears developing tropical cyclones apart, while low shear lets them organise and strengthen.
Microscopic photosynthetic algae living inside the tissues of reef-building corals in a symbiosis, supplying most of the coral’s food and giving it its colour.