Flashcards
Geography Module 2 Coastal Environments
Cards in this deck (76)
- 1FetchThe longer the distance that the surface of the sea is exposed to a continuous gust of wind the higher the waves will be.
- 2SwashThe energy of the wave that pushes up the beach.
- 3BackwashThe energy of the wave returning down the beach.
- 4BermA strong swash transports material up the beach to form a ____ .
- 5Storm beachA large berm may occur at the back/top of the beach where larger material is thrown during storms when the swash has more energy.
- 6Constructive wavesWaves:-
associated with calm weather
less powerful
longer wavelength and short height
stronger swash which deposits material
weaker backwash, therefore, less erosive. - 7Destructive wavesWaves:-
associated with stormy weather
more powerful due to longer fetch
high and steep with a shorter wavelength
stronger backwash than swash so tend to cause erosion by removing material from the beach/coast. - 8Abrasion/Corrasionparticles of sand and silt carried in suspension, rub against the beach and cliffs which are worn aways by a sandpapering action.
- 9Corrosionweak acids and natural salts in water affect the geology of the cliffs and dissolve rocks such as limestone and chalk.
- 10Hydraulic actionSheer force of water in the wave wears away cliffs and beach by dislodging small stones and grit.
- 11AttritionMaterial transported in waves collides and breaks into smaller pieces, this happens mainly where waves have a great deal of power due to a large fetch, over time this forms sand.
- 12TractionLarger material rolled in stormy seas where wave energy is high.
- 13SaltationSmaller pebbles bounced along the sea bed.
- 14SuspensionFine materials carried in the water.
- 15SolutionFine materials dissolved into the water.
- 16Longshore DriftThe transport of sediment along a stretch of coastline caused by waves approaching the beach at an angle.
- 17Prevailing windWind blowing mainly in one direction.
- 18WeatheringThe breaking down or decomposition of a material.
- 19Mechanical weatheringPhysical weathering such as salt weathering .
- 20Salt weatheringwhere salt crystals form in joints and cracks and expand, causing the mechanical breakdown of the rock.
- 21Freeze-thaw / frost shatteringWater enters a crack or joint and freezes. water expands upon freezing by about 9% and so gradually breaks the rock apart.
- 22Chemical weatheringCarbon dioxide contained in solution in both rain and seawater reacts with the minerals in carbonate rocks and dissolving them.
- 23Biological WeatheringInvolves marine organisms, plants and animals (including humans) breaking rocks, apart. molluscs may burrow into the rocks below/around the water level.
- 24Mass movementThe downwards movement of material under the force of gravity, common along coastlines where there are cliffs.
- 25RockfallsMay occur on coastlines with cliffs, where rock type is usually more resistant to erosion and has produced bedding planes and joints in its structure. These are the areas along which detachment can occur and undermining by waves may cause period falls of large segments.
- 26Sliding/SlumpingTends to occur on cliffs composed of less resistant, softer, geologies like sands and clays. Often triggered by periods of heavy rainfall, which saturates the rock and makes it heavier, slope failure can occur leading to the down-slope movement of material `en-masse`.
- 27Erosional LandformsSuch landforms are produced when, due to the force and power of wave action, the different processes of erosion act o the coastline to produce characteristic landforms.
- 28Discordant CoastlineFormed due to the geological structure of the rock on the coastline, where there are alternating bands of softer, less resistant rock and harder, more resistant rock facing the sea. where this geological structure occurs along the coastline.
- 29HeadlandWhere there is more resistant rock on a Discordant Coastline, such as chalk or limestone, erosion is slower and the rock stands out to the sea.
- 30BayWhere there are softer rocks on a Discordant Coastline, such as sands and clays, it is eroded more rapidly to form indentations.
- 31Wave-cut notchMarine Erosion at the base of a cliff undercutting it, over time the unsupported cliff above this may collapse as rockfall.
- 32Wave-cut-platformsConstant erosion (through hydraulic action, abrasion and perhaps corrosion on susceptible rocks) here produces a eave-cut-notch at the base which, over time, grows in size. As the notch increases in size, the weight of the cliffs above become too much and the cliff collapses. This material will provide temporary protection for the cliff behind. However, once it has been removed by the sea this process will occur again and, over time, the cliff retreats. A platform of eroded material and bedrock remains out to sea from the present cliff line.
- 33CavesFirst, a weakness in the geological structure of the rock is found and over time this small crack or crevice is exploited by wave action and eroded through hydraulic action (and perhaps corrosion on susceptible rock types). It enlarges and eventually forms a hollow.
- 34ArchIf located on a headland, the erosion may be such that a complete gap or hole is made through a headland.
- 35StackAs erosion continues, eventually an arch becomes so large that is can no longer support its own weight. it falls due to gravity, now an isolated pillar of rock.
- 36StumpA stack is eroded and will form a stump of eroded material in the final stage.
- 37Depositional Landformson the flip-side to erosional landforms, these occur when there is a loss of energy which causes the material that is being transported to be deposited.
- 38BeachThe area between the lowest spring tide level of the sea and the highest point reached by storm waves. characteristics are the result of the actions of waves upon it.
- 39Backshore, Foreshore and the NearshoreThe 3 sections of a beach.
- 40BermThere may be a series of these ridges, often marking out the relative levels of the average tides.
- 41Storm BeachFound at the top of a beach, is a berm composed of large material thrown there by the strong swash of stormy, high energy, seas.
- 42Beach CuspsSemi-circular depressions formed by the swash and backwash sorting the sediment, and these are commonly found at the low watermark.
- 43SpitA long and narrow ridge of sand or shingle, or both. At one end it is attached to the mainland; the other end reaches out into the sea.
- 44Spit FormationFormed from the eroded material which is carried by longshore drift along the coast, until it meets an obstacle, such as a bend in the coast, perhaps where there is a bay, or where a river mouth joins the sea. At this point, the longshore drift begins to deposit the material, which will build up to form a sediment bank.
- 45BarsOccur when a spit extends and develops across a bay where there is no river (if there was a river, the current would not allow the spit to completely `shut off` the bay). The bay is cut off and, in effect, becomes a lagoon.
- 46Eustatic sea-level changeThe term used to describe global changes in the sea level, caused by an actual change in the volume of water in the sea.
- 47Submergent featuresOccur with eustatic sea-level rise, include rias and fjords.
- 48Isostatic sea-level changeUsed to describe changes to sea level at a local scale. It is a change in the height of the land relative to the sea, rather than a change to the actual volume of water in the sea.
- 49EcosystemA system of living organisms that share the same habitat and depend on each other for survival.
- 50BiodiversityRefers to the number of different species that exist within an ecosystem. Accounts for all living organisms
- 51Salt MarshesUsually found in mid to high latitudes, and in coastal environments where sheltered water allows sediment to be deposited and accumulate. Once enough sand and silt has been laid down for land to become exposed at low-tide, plants suited to that environment colonise the site.
- 52Pioneer speciesThe first plants that colonise a new salt marsh specially adapted to the condition found in the inter-tidal zone (the area between low and high tide). Over time, these pioneers help to trap sediments, building up mudflats.
- 53Plant successionAfter mudflats are developed in a salt marsh with the help of pioneer species, more complex species grow in the changed conditions.
- 54Climax CommunityAs you move inland from a salt marsh, you see a series of changes where there has been more time for change, and the upper marshes may eventually become so developed that this area of ash/alder woodland may be seen.
- 55HalosereThe term used to describe succession in a salt marsh.
- 56Sand DunesThese are accumulations of sand that develop in areas of the coast where there is a large sediment input and where the wind usually blows onshore. they form initially where the wind-blown sand accumulates around an obstacle, like seaweed or driftwood.
- 57Embryo dunesStart to form as the mound of material grows. first dunes to develop.
- 58Sand Dune SuccessionThe newest embryo dunes at the front, then fordunes with the addition of humus, which is decayed organic matter from previous generations of marram allowing new species to grow, then grey dunes, so-called due to the change in colour that occurs as the soil becomes more developed. With the oldest dunes at the back, shrubs like gorse and, eventually small trees grow where there is water-retentive soil, and from the climax community at the far back of the system.
- 59Dune slacksIn between the dunes, damp hollows support water-loving species, including insects and animals.
- 60Coral ReefsCalcium and calcite mineral structures produced by living organisms. they are an entirely `living` ecosystem. like all ecosystems, they are composed of living (biotic) and non-living (abiotic) components.
- 61Barrier, Fringing and AtollThree main types of Reef.
- 62Formation of coral reefsAs a coral (or polyp, as it is more correctly called) grows, it produces a substance which hardens to form limestone. This provides the animal with a protective external skeleton. Most coral polyps manufacture this substance from waste products given off by tiny algae living in the coral's tissues and calcium ions absorbed from seawater. When a polyp dies, it's skeleton becomes part of the foundation of the growing reef.
- 63MangrovesAn ecosystem made up of trees and shrubs that grow in saline coastal environments in the tropics and subtropics. Can also refer to the family of plants, or the specific trees themselves.
- 64Mangrove DetailsFound in depositional coastal environments where fine sediments, often with high organic content, collect in areas protected from high energy wave action. Mangroves and therefore made up of tropical evergreen trees or shrubs growing in marshes along tidal shores.
- 65Energy FlowsCoastal ecosystems depend in the first instance on these, which derive from the sun. The sun warms the coast and coastal waters as well as the living creatures. Green plants life is dependent on sunlight for photosynthesis, a process by which plants convert carbon dioxide and water into oxygen and carbohydrate. Carbohydrate provides food for the plants. This gives rise to the food chain.
- 66Nutrient CyclingAt each stage of the food chain, nutrients are passed on, but when organisms die chemical nutrients are returned to the system.
- 67Special Area of Conservation (SAC)Strictly protected sites of listed habitat types and species considered to be most in need of conservation on the Northern Ireland coast.
- 68Storm SurgeOccurs where high tides combine with strong onshore winds to give unusually high sea levels. Also, in addition to high tides and high winds, low-pressure systems can cause the sea to bulge or expand.
- 69Shoreline Management PlanA document which is drawn up to describe and explain the character of that particular stretch of coastline, the risks posed by coastal erosion and flooding both the environmental and human 'Assets' present there, and to outline the defence and management plans.
- 70Hold the Line (coastal management)Maintain existing defences to maintain the present coastline.
- 71Advance the line (coastal management)Move existing defences forwards (seawards from the existing line of defence.
- 72Managed retreat / realignment (coastal management)Ceasing maintenance and/or removal of existing defences to allow coastal areas to flood, with careful monitoring of the impacts and extent inland.
- 73No active intervention (coastal management)no investment into providing any management or defence of a stretch of coastline.
- 74Hard EngineeringGenerally defined as controlled disruption of natural processes using man-made structures.
- 75GroynesWooden or concrete, these trap sediment being carried along the coast by longshore drift so that it builds upon the beach. They can widen beaches and reduce cliff erosion.
- 76Soft EngineeringThis is the use of ecological principles, practices and the surrounding natural environment to reduce erosion and achieve the stabilization and safety of shorelines and the seas surrounding rivers while enhancing habitat, improving aesthetics, and saving money.
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- Geography Module 2 Coastal Environments
- Created by
- William Sowden · Nov 2019
- Updated
- Jan 20, 2020
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