Coasts as Natural Systems

Question 1

What type of system is the coast?

Answer 1

An open system

Question 2

What is an open system?

Answer 2

One which interacts strongly with other systems eg. sediment is often from rivers

Question 3

What effect can feedbacks have on a system?

Answer 3

They can increase or decrease available inputs or outputs as well as enabling equilibrium

Question 4

When is a system in dynamic equilibrium?

Answer 4

When inputs and outputs of energy and matter are balances

Question 5

What type of events alter the coastline on a short term basis?

Answer 5

Storms

Question 6

What can dynamic equilibrium be affected by over geological (longer) time periods?

Answer 6

Supply of sand
Energy of the waves
Sea level change
Location of the shoreline

Question 7

What is a landform?

Answer 7

Individual features which are created by coastal processes

Question 8

What is a landscape?

Answer 8

The entire area of sea, coastline and immediate land behind the sea front. Within the landscape are characteristic landforms

Question 9

What are inputs?

Answer 9

Material or energy entering the system from outside sources/systems.

Question 10

What are flows/transfers?

Answer 10

Processes that link the inputs, outputs and stores in the coastal system.
Movement of material and energy.

Question 11

What are stores/sinks?

Answer 11

Parts of a system not necessarily in motion. Sediment and material.

Question 12

What are outputs?

Answer 12

Material/energy moving out of a system

Question 13

What are feedbacks?

Answer 13

Can be positive (leads to increase/amplification) or negative (leads to decrease/decline)

Question 14

What are some of the inputs into the coastal system?

Answer 14

Energy

Precipitation

Wind

Fluvial Sediment

Question 15

What are some of the flows/transfers in the coastal system?

Answer 15

Longshore drift
Mass movement
Weathering
Wind-blown sand
Erosion
Oceancurrents
Riptides

Question 16

What are some of the outputs from the coastal system?

Answer 16

Ocean currents
Riptides
Sediment transfer
Evaporation

Question 17

What is energy?

Answer 17

The power and driving force behind the transfers and flows in the system.

Wind
Gravitational
Flowing water

Question 18

Example of a negative feedback loop

Answer 18

1. When the destructive waves from the storm lose their energy excess sediment is deposited
   as an offshore bar.
2. The bar dissipates the waves energy which protects the beach from further erosion.
3. Over time the bar gets eroded instead of the beach.
4. Once the bar has gone normal conditions ensue and the system goes back to dynamic
   equilibrium.

Question 19

Example of a positive feedback loop

Answer 19

1. People walking over sand dunes destroys vegetation growing there and
   causes erosion.
2. 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.
3. 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.

Question 20

What are some of the stores in the coastal system?

Answer 20

● Beaches
● Sand Dunes
● Spits
● Bars and Tombolos
● Headlands and Bays
● Nearshore Sediment
● Cliffs
● Wave-cut Notches
● Wave-cut Platforms
● Caves
● Arches
● Stacks
● Stumps
● Salt Marshes
● Tidal Flats
● Offshore Bands and Bars