Key Terms: Coasts as Natural Systems (AQA A Level Geography): Revision Note

Coasts as a system - key terms

Atmosphere – The layer of gases surrounding the Earth; contributes wind, precipitation, and weather to the coastal system.

Biosphere – The living component of the Earth; vegetation and human activity that can influence coastal processes.

Closed system – A system with no inputs or outputs from outside its boundaries; sediment cells at the coast are often studied this way in coastal management.

Cryosphere – The frozen water part of the Earth system (e.g. glaciers), which can supply sediment to coastal areas.

Dynamic equilibrium – A state of balance within a system where inputs and outputs are equal over time, though temporary imbalances may occur.

Evaporation – The process by which water changes from liquid to vapour; an output from the coastal system.

Feedback loop (positive) – A process that amplifies change; for example, cliff erosion creates more material, increasing abrasion and further erosion.

Feedback loop (negative) – A process that reduces or counteracts change; for instance, material from cliff erosion widens the wave-cut platform, which absorbs wave energy and slows further erosion.

Hydrosphere – The water component of the Earth system, including rivers and seas, providing energy and sediment to coasts.

Inputs – Elements that enter the coastal system, such as sediment from rivers, precipitation, and wave energy.

Lithosphere – The rocky outer shell of the Earth; contributes sediment and structure to coastal systems through erosion and tectonic activity.

Longshore drift – A transportation process where sediment moves along the coast due to wave action striking at an angle.

Mass movement – The downslope movement of sediment or rock under gravity, contributing to coastal sediment transfer.

Open system – A system that receives inputs and produces outputs from and to other systems; describes the coast as it interacts with land, sea, and atmosphere.

Outputs – Elements that leave the coastal system, such as eroded sediment transported out to sea.

Precipitation – Rainfall or other forms of moisture entering the system from the atmosphere; contributes to runoff and weathering.

Sediment cell – A stretch of coastline where sediment movement is largely self-contained; used as a framework in coastal management.

Stores – Parts of the coastal system where material is held, such as beaches, dunes, and cliffs.

Transfers – The movement of material within the coastal system, including processes like longshore drift, wind-blown transport, and wave action.

Wave-cut platform – A flat area of rock in front of a cliff, formed by erosion, which can reduce the impact of waves at the base of the cliff.

Wind-blown sand – Sediment moved by wind, especially in dune formation and sediment redistribution along the coast.