Coastal Environments - Introduction
Coasts as Natural Systems
- Coasts can be studied using a systems approach, like the carbon cycle and water cycle.
- Systems have inputs, outputs, stores, and flows.
- Coastal systems are open systems (matter and energy can be transferred in and out).
- Inputs: Wind energy, wave energy, tides, sea currents.
- Stores: Landforms of erosion and deposition.
- Flows: Wind or water transport (erosional or depositional processes).
- Outputs: Accumulation of sediment, dissipation of wave energy.
Dynamic Equilibrium and Feedback
- Coastal landscapes are always changing due to feedback processes.
- Positive Feedback: Effects of a process are amplified.
- Negative Feedback: Effects are nullified to maintain balance.
- Systems aim for dynamic equilibrium (balance between inputs and outputs).
- Example of negative feedback:
- Beach in dynamic equilibrium.
- Storm causes sediment erosion.
- Sediment forms offshore bar.
- Offshore bar reduces wave erosion on beach.
- Sediment returns to beach post-storm.
Coastal Zones
- Backshore: Between high water mark and landward limit of marine activity; changes only during storms.
- Foreshore: Between high water mark and low water mark; significant for marine activity.
- Inshore: Between low water mark and point where waves stop influencing land.
- Offshore: Beyond point where waves impact seabed; limited to sediment deposition.
- Nearshore Zone: Between high water mark and where waves break.
- Swash Zone: Upper part; area where water washes up the beach after wave breaks.
- Breaker Zone: Area where wave actually breaks.
- Surf Zone: Between breaker zone and swash zone.
Summary
- Coastal zones are essential for understanding coastal processes.
- Future videos will refer to these zones for better comprehension.
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