Cosatal Systems And Landscapes Flashcards
what is an input in a coastal system?
sediment being brought into a system
where do energy inputs in coastal systems come from?
Wind, waves, tides and currents
What is an output in a coastal system?
Sediment being washed out to sea
What is an example of a flow or transfer?
Processes such as erosion, weathering, transportation and deposition
What is an example of a store or component in a coastal system?
Landforms such as beaches dunes and spits
What does dynamic equilibrium mean?
Inputs and outputs are balanced
In a dynamic equilibrium what does a change in the output or input cause?
Negative feedback to restore the system
Give an example of negative feedback
As a beach is eroded the cliffs behind are exposed to wave attack, sediment eroded from the cliffs is deposited on the beach causing it to grow in size again
What is positive feedback?
When a change in the system causes other changes that have a similar effect
Give an example of positive feedback
As a beach starts to form it slows down waves which causes more sediment to be deposited increasing the size the beach. The equilibrium is reached when long term growth of the beach stops
In the costal system how is energy transferred?
Air (as wind) and water (waves, tides and currents)
How are winds created?
Air moving from areas of high pressure to areas of low pressure
What can strong winds generate?
Powerful waves
What are prevailing winds?
Wind consistently blowing in the same direction
What gives water circular motion on waves?
Friction between the wind and the surface of the sea
What is wave height affected by?
Wind speed and the fetch of the wave
What is the fetch?
The maximum distance if sea the wind has blown over
What is the swash?
Water washing up the beach
What is the backwash?
Water washing back towards the sea
What are the two types of wave?
Constructive and destructive waves
Constructive waves
Low frequency (6-8 per minute) Low and long giving an elliptical cross profile Powerful swash deposits material
Destructive waves
High and steep with a circular cross profile
Higher frequency (10-14 waves per minute)
Strong backwash removes material
What is a tide?
The periodic rise and fall of the ocean surface caused by the gravitational pull of the moon and sun
What do tides affect the position of?
That waves break on the beach
Define an open system (3 marks)
An open system is a system that transfers both energy and matter across its boundary to the surrounding environment
Most ecosystems are examples of open systems
Elements make up a system e.g sand grains, atoms, plants and animals
Attributes are characteristics of the elements that may be perceived or measured
Relationships are associations between elements and attributes
Name an input, process and output of the coastal system (3 marks)
Input: waves, rock types, weather, human activities
Process: wreathing and mass movement
Output: erosional landforms
