Coastal Systems and Landscapes: Coasts as natural systems Flashcards
Systems in physical geography: systems concepts and their application to the development of coastal landscapes – inputs, outputs, energy, stores/components, flows/transfers, positive/negative feedback, dynamic equilibrium. The concepts of landform and landscape and how related landforms combine to form characteristic landscapes.
Give inputs to a coastal system:
- Waves
- Wind speed
- Tides
- Sun
- Air pressure
- Pollution
- Defences
What are inputs in a coastal system?
The addition of energy or material into a system.
How are waves formed from the wind?
Transfer of energy from the wind blowing over the sea surface.
Give the outputs of coastal system:
- Ocean currents
- Rip tides
- Sediment transfer
- Evaporation
What is it called when the inputs and outputs in a system are balanced?
Dynamic equilibrium.
Why can coasts be considered an open system?
It receives inputs from outside the system and transfers outputs away from the coast and into other systems.
What is a dynamic equillibrium?
- The maintenance of a balance in a natural system, despite it being in a constant state of change.
- The system often counteracts any changes to the system through changing inputs and outputs to maintain the balance.
What are outputs in a system?
The removal of energy/material out of a system.
Give stores within a coastal system:
- Beaches
- Sand dunes
- Landforms (e.g. spits, bars, headlands)
- Salt marshes
What are stores within a system?
Stores and sinks of sediment and material.
What are transfers within a system?
The processes that link the inputs, outputs and stores within a coastal system.
Give examples of transfers within a coastal system:
- Wind blown sand
- Mass movement
- Longshore drift
- Weathering
- Erosion
- Transportation
- Deposition
What are the 4 types of erosion?
- Hydraulic action
- Corrosion
- Attrition
- Abrasion
What are the 4 types of transportation?
- Bedload
- Suspension
-Traction - Solution
What are positive feedback loops?
Exaggerates a change in a system, making it more unstable and taking it away from the dynamic equilibrium.
Give an example of a positive feedback loop in a coastal system:
- People walking over sand dunes destroys vegetation growing there and causes erosion.
- As the roots from the vegetation have been holding the sand dunes
together, damaging the vegetation makes the sand dunes more
susceptible to erosion. This increases the rate of erosion. - Eventually the sand dunes will be completely eroded leaving more of the beach open to erosion taking the beach further away from its original state
Give an example of a negative feedback loop in a coastal system:
- When the destructive waves from the storm lose their energy excess sediment is deposited as an offshore bar.
- The bar dissipates the waves energy which protects the beach from further erosion.
- Over time the bar gets eroded instead of the beach.
- Once the bar has gone normal conditions ensue and the system goes back to dynamic equilibrium.
What are negative feedback loops?
Lessens any change which has occurred within the system.
What is attrition?
Material in the water hitting each other.
What is abrasion?
When material is picked up and thrown against the cliffs.
What is hydraulic action?
Sheer force of the waves
Define mass movement:
The downslope movement of material, such as mud, rock or soil.
