How can coastal landscapes be viewed as systems?
Coastal Systems Defined
- Coasts are considered systems because they incorporate a diverse set of components which interact with each other to enable processes and changes.
- The system can be based on three major concepts: inputs, processes, and outputs.
- Inputs are the energy and material that are introduced into the system, such as waves, tides, marine organisms, sediments, and humans.
- Processes are the physical, biological or chemical events or transactions that modify the inputs, such as weathering, erosion, transportation, deposition, and biological activity.
- Outputs refer to the resultant landforms and materials exported from the system, for example deposited sediment or eroded cliffs.
Open and Closed Coastal Systems
- Coasts can be classified as either open or closed systems.
- An open system has both inputs and outputs to and from other systems. Most natural systems, including coasts, are considered open.
- A closed system has no exchange with other systems. It is self-contained regarding energy and material flow.
Energy Flows in Coastal Systems
- Energy enters coastal systems in several ways, including: solar radiation, gravity, and tidal energy from the moon. These are important drivers of the processes that shape coastal landscapes.
- Waves, tides and currents are critical forms of kinetic energy in coastal systems, operating as agents of coastal change.
Material Flows in Coastal Systems
- Coastal systems also involve significant material flows including fluvial inputs, marine sediment, and weathered material from cliffs.
- The nature and rate of these material flows can exert significant influence on coastal shape, form and dynamic behaviour.
Feedback Mechanisms
- Feedback mechanisms can be either positive or negative, serving to amplify or decrease changes within the system respectively.
- An example of positive feedback would be where the erosion of a cliff base leading to collapse of the cliff face, provides more material to be eroded and further collapsing.
- An example of negative feedback would be where increased vegetation stabilises a dune system, reducing the potential for wind erosion.
Human Influence on Coastal Systems
- Humans can be both inputs and outputs of a coastal system.
- Human inputs can manifest in various forms ranging from physical alteration (like constructing sea defences) to indirect effects through climate change.
- Human outputs include use of marine resources, tourism, and integration into wider economic systems.
This systematic approach to understanding coastal landscapes provides a useful framework for analysing and predicting changes over time due to natural and anthropogenic influences.