7/30/2019 Essay Deconstruction and Analysis

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For one named ecosystem, outline the reasons for its formation and discuss how it develops over time (25)

Outline the conditions for Coral reef formation

Make a point Explain the point Give evidence /

Use a case study

Link back to

question

Climate

Coral needs the right

climate to form

Coral reef forms almost entirely within

the tropics and where ocean

temperatures are above 18 degrees

Celsius. Coral grows better where

temperatures are between 23 and 25degrees Celsius.

Coral forms in many

tropical regions

around the world

including the

Caribbean, SouthEast Asia, Northern

Australia and around

volcanic islands.

Coral reefs are

unique marine

ecosystems which

can only form with

very specificconditions.

Wave currents

Coral needs well

oxygenated salt water to

grow effectively

Tropical waters nutrient

deficient

Coral grows best in areas where there is a

large enough fetch to create a strong

wave action as this oxygenates the water.

Coral only grows in saline water.

Other factors

Light levelsWater depth

Nutrient Deficient water

Coral needs high light levels to form and

thus usually forms in waters less than

25m deep.

Nutrient deficient water is much clearer

increasing the light levels

Outline the theory of coral reef formation (diagram)

When the conditions are correct coral reef can begin to form. Its formation is very slow taking tens of thousands of

years. Darwin created a theory for how reefs develop over time.

Explain how coral reefs develop over time

Make a point Explain the point (diagram?) Give evidence /

Use a case study

Link back to

question

Coral develops naturally

over time through the

process of succession.

Stages of succession

1. A hard or rocky substrate free ofalgae is needed so that the small

coral recruits, or polyps, could attach

Line Islands

Pristene coral

environment.

Coral naturally

changes over

time due to the

process of

Introduction: What is coral reef? How will you answer the question?

Coral reef is made up entirely of living organisms (such as Polyps) and the deposits of calcium carbonate

which they produce.

Answer structure: Outline conditions. Darwins theory of formation. Change over time. Succession.Natural hazards Volcanoes / Tropical Storms. Human Impact.

7/30/2019 Essay Deconstruction and Analysis

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and begin to multiply into a coral

colony.

2. The coral colonies would thenprovide food, space, and shelter for

other reef creatures, including

herbivores.

3. Then, carnivorous fish andinvertebrates would multiply and

feed on the herbivores.

4. As biodiversity increased, additionalniches would develop. And in the

case of the more pristine Line Islands,

the reef supported more predators

than herbivores and showed signs of

stability and resilience.

succession.

However this

process is very

slow and can

take tens of

thousands of

years.

Coral can change over

time due to disturbance

from hazards

e.g. Volcanoes

Tropical Storms

Lava flows can destroy or damage existing

coral, however they also create new algae free

rocky substrate to which polyps can attach

Tropical storms can generate large waves

which damage the structure and integrity ofcoral reefs. This can reduce biodiversity in the

coral.

Tropical storms can also benefit coral by

reducing thermal stress from high ocean

temperature as they cause upwelling of cooler

water and transfer latent heat out of the

ocean. This helps maintain conditions for a

healthy reef.

E.g. Hawaiian Coral

Reef

Natural hazards

can both benefit

and destroy

biodiversity in a

coral reef

ecosystem.

Coral Reef ecosystems

can rapidly change due to

human influence

Idea of scale

Global scale coral reef systems are changing

due to climate change as increasing ocean

temperatures add thermal stress to the coral.

Globally but also at a local scale overfishing

and pollution leading to coral bleaching.

In many areas where reefs are important to

humans, for fishing / tourism plans for

sustainable use are being implemented but

not always successfully

St Lucia.

Economy based ontourism, and

fishing.

1992 plan to limit

coral damage by

creating the

Soufriere Marine

Management Area

to limit fishing in

certain areas

Humans can

have rapid

negative impacton coral reefs

causing rapid

loss of

biodiversity if

not managed

correctly

In Conclusion

Coral Reefs have specific conditions for formation and there are three different types as identified by

Darwin.

Coral Reefs naturally change over time due to succession and natural competition within species. This

process is very slow.

Natural Hazards can change coral reef ecosystems very quickly, and can have both positive and negative

effects on the biodiversity of coral.

Humans generally only have negative impact on coral reef systems although as understanding and

management improves our impact should decrease.