how can coastal landscapes be viewed as systems?

introduction

system - a set of interrelated objects comprising of components (stores) and processes (links)
coastal landscape systems store and transfer energy and material on varying time scales
energy may be kinetic (movement), thermal (heat), potential (energy due to position)
material is typically sediment - found on beaches, estuaries, nearshore zones (shallow water area at beach)

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coastal landscapes recognised as open systems - energy and matter can be transfered from neighbouring systems as an input
can also be transfered in neighbouring systems as an output
coastal landcape has:
- inputs: kinetic energy from wind and waves, thermal energy from sun, potential energy from position of material on slopes, marine deposition weathering and mass movement from cliffs
- outputs: marine and wind erosion of beaches and rock surfaces, evaporation
- throughputs: stores; beach and near shore sediment accumulations, flows; transfers of sediment such as longshore drift

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equilibrium - when a systems inputs and outputs are equal
- could occur when rates of sediment added to beach are equal to sediment removed from beach
dynamic equilibrium - inputs and outputs are no longer equal, and so the system undergoes self-regulation to restore equilibrium
- this is an example of negative feedback - decreases amount of change by reducing some of the inputs

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sediment cell - stretch of coastline where sediment movement is self contained
regarded as a closed system - no sediment moves from one cell to another
- unlikely that cells are completely closed, as variations in wind directions and global currents will cause a little movement of sediment between cells
11 sediment cells around coast of England and Wales
- examples include St Abbs Head, Flamborough Head and Land's end
boundaries determined by topography (shape of the landscape) and shape of coastline
- large physical features act as natural barriers, that prevent the transfer of sediment to other cells
sub-cells also exist in major cells

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