1 | The Natural State of the Coastal Environment

Sun, sea and sand

Tourists are initially attracted to clean water and sand, recreation, and healthy local flora and fauna - 'getting away from it all'.

The coastal environment is initially in a healthy state of balance.

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An Environment in Balance


Causal loop diagram: nature in equilibrium

Natural beaches may take thousands of years to evolve.

The natural coastal environment has the ability to regenerate, or renew itself, naturally. It can deal with naturally occurring degeneration, and maintains a consistently healthy state.

This constantly changing but stable state is called 'dynamic equilibrium'.

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Systems Concepts

Causal loop diagram: nature in equilibrium

Stocks

In the diagram, the stock is Environmental Quality. Stocks are entities that can accumulate or be depleted. Other examples are a bank account and a bathtub.

Flows

In the diagram, the inflow is Regeneration Rate, and the outflow is Degeneration Rate. An inflow increases a stock, and an outflow decrease it. Flows are rates - amounts over time.

A Stock Changes Only According to its Flows

Causal loop diagram: nature in equilibrium
  • If the inflow is greater than the outflow, then the stock will increase.
  • If the outflow is greater than the inflow, then the stock will decrease.
  • If the inflow is equal to the outflow, then the stock level will be constant ('dynamic equilibrium').

The stock level accumulates according to the net flow (inflow minus outflow) at each point in time.

Ocean Literacy Concepts

What factors increase the Degeneration Rate?

Tourists bring with them many threats to environmental quality, such as litter, waste and pollution. These degrade the coastal environment.

What factors increase the Regeneration Rate?

To help restore the natural balance, we can introduce measures such as planning laws, planting trees, protecting sand dunes etc.

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Explore for yourself:


Initially the line representing Environmental Quality is straight, with value unchanging, because inflow and outflow rates are equal ('dynamic equilibrium').

Use the dials under the graph to change the rates and see the effect on the line

Regeneration Rate (%)
[the INFLOW]

Degeneration Rate (%)
[the OUTFLOW]


1 What happens if the Regeneration Rate is higher than the Degeneration Rate?

2 What happens if the Degeneration Rate is higher than the Regeneration Rate?

Show answers »
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Question 1:
Which of the following scenarios will lead to a DECREASE in a bank balance over time?

Check all that apply:

€50 paid in and €50 withdrawn every month
€50 paid in every month and €300 withdrawn twice per year
€10 paid in every month and €50 withdrawn every two months
€10 withdrawn every month
€20 paid in every month

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Question 2:
Consider a bathtub, with taps supplying water, and a plug hole to drain it. Which of these represents a state of 'dynamic equilibrium'?

Taps are on, plug is closed
Taps are on, plug is open, letting out half the water coming in
Taps are on, plug is open, letting out exactly the amount of water coming in
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