A LevelGeographyAQAExam QuestionsEcosystems Under StressMarine Ecosystems

Marine Ecosystems (AQA A Level Geography): Exam Questions

Exam code: 7037

2 hours14 questions
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1
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1 mark

Where are coral reefs typically found?

  • Coral reefs form in latitudes between 30o north and south of the equator. Sea temperatures ideally need to be around 26 oC. Coral reefs are unlikely to exceed depths of 50 metres.

  • Coral reefs form wherever there is a sufficient food source and calm water. The upwelling of cold currents around 12 oC brings an ample supply of phytoplankton and zooplankton, a key food source.

  • Algal blooms in the high latitudes at 60o north provide the ideal circumstances for coral reef formation. Deep water coral is found off the east coast of Australia – the Great Barrier Reef.

  • Coral is found anywhere on the planet. Provided the water is free from pollution and well sheltered from strong currents, some coral will form. It will not form in warm sea water.

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2
1 mark

Which of the following best describes the relationship between coral polyps and zooxanthellae?

  • A mutualistic relationship: the zooxanthellae photosynthesise and pass food and oxygen to the polyp, while the polyp provides the algae with shelter and carbon dioxide.

  • A parasitic relationship: the zooxanthellae live inside the polyp and slowly weaken it by taking its nutrients.

  • A competitive relationship: the polyp and the zooxanthellae compete for the same sunlight and food in the water.

  • A predatory relationship: the polyp feeds directly on the zooxanthellae as its main source of food.

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3
1 mark

What is the main cause of coral bleaching?

  • A rise in salinity coates the coral with salt crystals

  • A fall in sea temperature freezes the coral polyps, turning the reef white.

  • An increase in sunlight causes the coral to grow a thick white protective layer.

  • A rise in sea temperature stresses the coral, causing it to expel its zooxanthellae and lose its colour.

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4
4 marks

Outline the environmental conditions needed for coral reefs to grow.

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5
4 marks

Outline how human activity, other than climate change, can threaten coral reefs.

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1
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9 marks

Figure 12 Information about coral reefs

coral-reef-infographic

Figure 12 shows information about coral reefs.

Using Figure 12 and your own knowledge, assess the implications of this information for the management of coral reefs.

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2
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9 marks

Figure 12a shows coral bleaching in the Great Barrier Reef (GBR), Australia, in 2016.

Figure 12b shows estimated change in sea water pH caused by human-created CO2 between the 1700s and the 1990s.

Figure 12c shows the sea surface temperature anomaly for the Coral Sea, Australia, between 1900 and 2016.

Figure 12a – coral bleaching in the Great Barrier Reef (GBR), Australia, in 2016

fig-12a-inserts-paper1-nov2020-aqa-alevel-geography

Note: When water is too warm, corals will expel the algae living in their tissues causing the coral to turn completely white. This is the process of coral bleaching.

Figure 12b – estimated change in sea water pH caused by human-created CO~2~ between the 1700s and the 1990s

fig-12b-inserts-paper1-nov2020-aqa-alevel-geography

Figure 12c – sea surface temperature anomaly for the Coral Sea, Australia, between 1900 and 2016

fig-12c-inserts-paper1-nov2020-aqa-alevel-geography

Note: The anomaly is measured against the mean for the period 1960–1991.

Using Figures 12a, 12b, 12c and your own knowledge, assess the scale of the threat facing this coral reef.

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3
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9 marks

Evaluate the impact of human activity upon the future prospects for coral reefs.

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4
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9 marks

Assess the importance of global governance in securing the long-term health and survival of coral reefs.

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5
9 marks

Assess the extent to which human activity poses a greater threat to coral reefs than natural processes.

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6
9 marks

How far do you agree that changes to the carbon cycle are leading to an increasingly uncertain future for coral reefs?

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1
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20 marks

‘It is impossible to achieve economic development within marine ecosystems whilst adhering to the principles of sustainability.’

To what extent do you agree with this view?

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2
20 marks

Assess the view that the future of coral reefs depends more on tackling global threats than on local management strategies.

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3
20 marks

'The loss of coral reef ecosystems would have greater consequences for people than for the natural world.'

How far do you agree with this statement?

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