Lesson 3.1.6.5

3.1.6.5 Marine ecosystems Quiz: AQA Geography, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.6.5, Marine ecosystems: 20 multiple choice questions for the AQA Geography (7037), Unit 1: Physical geography, written with Revision Ninja.

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The 20 questions

  1. What marine environmental condition is essential for reef-building coral growth?

    • Cold, nutrient-rich water
    • Deep, turbid water
    • Shallow, clear water
    • Brackish estuarine water

  2. What is the ideal mean annual water temperature range for healthy coral reef growth?

    • 23–25 °C
    • 12–15 °C
    • 5–10 °C
    • 32–38 °C

  3. What type of ecological relationship exists between reef-building corals and zooxanthellae algae?

    • Commensalism
    • Parasitism
    • Predation
    • Mutualism

  4. Which natural abiotic factor causes severe stress and bleaching in corals when sustained above normal levels?

    • Substrate density
    • Tidal range
    • Water temperature
    • Water velocity

  5. What cellular event directly causes a coral reef polyp to turn white during bleaching?

    • Nematocyst discharge
    • Expulsion of zooxanthellae
    • Calcium accumulation
    • Polyp mitosis

  6. Which coastal activity causes coral smothering by increasing sediment runoff into the ocean?

    • Desalination
    • Dredging
    • Ecotourism
    • Overfishing

  7. Which ecological event triggered by nutrient pollution directly smothers and harms coral reefs?

    • Bioaccumulation
    • Ocean warming
    • Algal bloom
    • Coral bleaching

  8. Which factor causes localized coral stress near desalination plant outfalls?

    • Low oxygen
    • High turbidity
    • High salinity
    • Low acidity

  9. What waste product from desalination plants increases marine salinity and stresses coral reefs?

    • Toxic heavy metals
    • Thermal discharge
    • Brine discharge
    • Plastics pollution

  10. Which global phenomenon causes ocean acidification, threatening future coral reef skeletal growth?

    • Ozone depletion
    • Carbon emissions
    • Eutrophication
    • Plastic pollution

  11. Which material is carried into marine ecosystems by rivers altered by drainage basin schemes?

    • Radioactive waste
    • Microplastic beads
    • Oil spills
    • Agricultural sediment

  12. Which direct physical damage is frequently caused to shallow coral reefs by tourists?

    • Anchor damage
    • Ocean acidification
    • Algal blooms
    • Thermal stress

  13. Which natural mechanism allows damaged coral reefs to recolonise and recover over time?

    • Thermal adaptation
    • Salinity reduction
    • Coral larval supply
    • Photosynthetic increase

  14. Why are local coral reef conservation strategies often insufficient on their own?

    • Lack of funding
    • Low salinity levels
    • Tourist presence
    • Global ocean warming

  15. What happens to coral cover when excess agricultural runoff enters a reef ecosystem?

    • Decreased coral cover
    • Increased biodiversity
    • Faster calcification
    • Higher water clarity

  16. Within which latitudinal zone are the majority of coral reefs located?

    • 30°N to 60°N
    • 60°N to 90°N
    • 30°S to 60°S
    • 30°N to 30°S

  17. Which symbiotic organism living inside coral tissues determines its tolerance to sea temperature rises?

    • Cyanobacteria
    • Zooxanthellae
    • Phytoplankton
    • Sea anemones

  18. Which chemical ion becomes less available to corals during ocean acidification?

    • Nitrate ions
    • Carbonate ions
    • Sodium ions
    • Sulphate ions

  19. Which structural characteristic of coral reefs supports their exceptionally high species biodiversity?

    • Complex 3D structure
    • High water turbidity
    • Monoculture coverage
    • Flat sandy seabed

  20. When corals expel their symbiotic algae due to heat stress, what process has occurred?

    • Bioaccumulation
    • Eutrophication
    • Coral bleaching
    • Ocean acidification

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