1.a Coastal landscapes can be viewed as systems

What is a system?

• A set of interrelated objects comprising components and processes that are connected together to form a working unit

What kind of energy is stored by a coastal landscape?

• Kinetic

• Potential

• Thermal

What kind of systems are coastal landscapes?

• Open systems - no sediment is transferred to a neighbouring cell

What are nearshore zones?

• The area of coastal environment between mean high tide and mean low tide

What are inputs?

• Energy - kinetic, thermal and potential

• Marine deposition of materials

• Weathering, mass movement from cliffs

What are outputs?

• Marine and wind erosion

• Evaporation

What are throughputs?

• Stores - beach, nearshore sediment accumulations

• Flows - movement of sediment along a beach by longshore drift

What is equilibrium in a coastal system?

• Rate at which sediment is being added to a beach (input) = rate at which sediment is being removed (output)

What is dynamic equilibrium?

• System produces its own response to the disturbance (e.g, erosion)

What is positive feedback?

• Equilibrium is disturbed

• System does not produce its own response to the disturbance - etc., processes accelerate

What is negative feedback?

• Equilibrium is disturbed

• System produces its own response to the disturbance

What are sediment cells?

• A stretch of coastline and its associated nearshore area within which the movement of coarse sediment, sand and shingle is contained

What kind of systems are sediment cells?

• Closed systems - no sediment is transferred to a neighbouring cell

Which factors determine the boundaries of sediment cells?

• Topography (forms of land surfaces)

• Shape of the coastline

Which factors block the transfer of sediment at sediment cells?

• Large physical features - natural barriers that prevent the transfer of sediment to adjacent cells

Why is it uncertain that sediment cells are completely closed?

• Variations in wind direction

• Presence of tidal currents

• Some sediment is transferred