Lesson 3.3.3

3.3.3 How and in what ways do human activities pollute oceans? Quiz: OCR Geography, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.3, How and in what ways do human activities pollute oceans?: 20 multiple choice questions for the OCR Geography (H481), Unit 7: Exploring Oceans, written with Revision Ninja.

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The 20 questions

  1. Which main greenhouse gas dissolves in ocean water to directly cause ocean acidification?

    • Sulfur dioxide
    • Carbon dioxide
    • Methane
    • Nitrous oxide

  2. Which toxic heavy metal accumulates in marine food chains through the process of biomagnification?

    • Mercury
    • Cadmium
    • Arsenic
    • Lead

  3. Which response technique uses chemical agents to break floating oil slicks into smaller droplets?

    • Booms
    • Dispersants
    • Skimmers
    • Sorbents

  4. Which circular system of ocean currents concentrates floating plastic waste into dense ocean patches?

    • Gyre
    • Rift valley
    • Upwelling
    • Trench

  5. Ocean acidification primarily reduces the availability of which compound required for marine shell formation?

    • Sodium chloride
    • Calcium carbonate
    • Potassium nitrate
    • Magnesium sulfate

  6. What process occurs when heat-stressed corals expel their symbiotic zooxanthellae algae into ocean waters?

    • Coral bleaching
    • Ocean acidification
    • Biomagnification
    • Eutrophication

  7. What term describes the expansion of ocean water volume caused directly by rising sea temperatures?

    • Eustatic melting
    • Capillary action
    • Thermal expansion
    • Isostatic rebound

  8. What term measures the percentage of incoming solar radiation reflected by Arctic sea ice?

    • Albedo
    • Insolation
    • Latent heat
    • Specific heat

  9. Synthetic microfibres washed into oceans from domestic laundry belong to which major class of pollutants?

    • Heavy metals
    • Nuclear waste
    • Microplastics
    • Crude oil

  10. Which floating physical barrier is deployed on ocean surfaces to prevent oil slicks from spreading?

    • In-situ burning
    • Containment booms
    • Skimmer boats
    • Dispersants

  11. In which major ocean gyre is the Great Pacific Garbage Patch situated?

    • North Atlantic Gyre
    • South Atlantic Gyre
    • Indian Ocean Gyre
    • North Pacific Gyre

  12. Decreasing ocean pH directly damages shell development, threatening which commercial coastal sector?

    • Commercial shipping
    • Deep-sea mining
    • Aquaculture
    • Offshore wind

  13. The melting of which ice source transfers fresh water to oceans, directly driving sea level rise?

    • Sea ice floes
    • Atmospheric clouds
    • River ice
    • Land ice sheets

  14. Constructing seawalls and planting mangroves on vulnerable islands are examples of which sea level response?

    • Adaptation strategies
    • Geoengineering
    • Preservation
    • Mitigation strategies

  15. Replacing reflective sea ice with dark ocean water accelerates Arctic warming through which feedback loop?

    • Radiative damping
    • Positive feedback
    • Thermal equilibrium
    • Negative feedback

  16. Which form of industrial marine pollution creates long-term biohazard hazards from nuclear facilities?

    • Radioactive waste
    • Eutrophic runoff
    • Heavy crude
    • Organic sewage

  17. Photodegradation breaks floating marine plastics into smaller fragments through the action of what?

    • Wave action
    • Ultraviolet light
    • Bacterial enzymes
    • High salinity

  18. What threshold in a climate system leads to irreversible sea ice loss once crossed?

    • Equilibrium state
    • Thermal limit
    • Tipping point
    • Feedback baseline

  19. Which ocean cleanup method uses specialised bacteria to break down crude oil hydrocarbons?

    • Biomagnification
    • Bioremediation
    • Bioaccumulation
    • Phytoremediation

  20. How does the pH level of ocean surface waters change as atmospheric carbon dioxide dissolves?

    • It fluctuates
    • It increases
    • It decreases
    • It stays constant

All OCR Geography quizzes