New
New
Year 9

Threats to oceans

I can explain the main threats to oceans and how they affect marine environments.

New
New
Year 9

Threats to oceans

I can explain the main threats to oceans and how they affect marine environments.

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Lesson details

Key learning points

  1. Plastic pollution harms marine life and spreads through ocean currents.
  2. Overfishing reduces fish populations and disrupts marine food chains.
  3. Climate change warms oceans and causes coral bleaching.
  4. Oil spills and chemical pollution damage marine ecosystems.
  5. Rising sea levels and acidification threaten coastal and ocean habitats.

Keywords

  • Ocean current - continuous movements of seawater in the ocean

  • Overfishing - catching too many fish, so the breeding population becomes too depleted to recover

  • Food chain - a sequence that shows how a group of living things are linked by what they eat

  • Ocean acidification - when the ocean becomes more acidic because it absorbs too much CO₂ from the air

Common misconception

Ocean acidification is when water is polluted from human activities on land.

Ocean acidification is when the ocean absorbs extra carbon dioxide (CO₂) from the air, which makes the water more acidic.


To help you plan your year 9 geography lesson on: Threats to oceans, download all teaching resources for free and adapt to suit your pupils' needs...

Ask students to do some extra research on the 1996 Milford Haven Oil spill, looking at the causes and effects.
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Equipment

Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Prior knowledge starter quiz

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6 Questions

Q1.
What does the term 'Anthropocene' describe?

A period when dinosaurs existed
A future time of total environmental balance
Correct answer: The current era shaped by human activity
A scientific term for volcanic activity

Q2.
Which of these is a human activity that directly contributes to climate change?

Planting trees
Correct answer: Burning fossil fuels
Walking instead of driving
Using solar panels

Q3.
What is a consequence of overfishing?

Cleaner oceans
Balanced marine food webs
Correct answer: Collapse of fish populations
Increased fish biodiversity

Q4.
Deforestation often reduces and increases CO₂ levels.

Correct Answer: biodiversity

Q5.
What does your carbon footprint measure?

How far you walk each day
The size of your shoe
Your impact on wildlife
Correct answer: Your personal contribution to emissions

Q6.
Which of these is a sustainable action?

Buying fast fashion
Eating imported food only
Correct answer: Using public transport
Leaving lights on all day

Assessment exit quiz

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4 Questions

Q1.
Match the keywords to their definitions:

Correct Answer:Ocean current,Continuous movement of seawater

Continuous movement of seawater

Correct Answer:Overfishing,Catching too many fish to allow recovery

Catching too many fish to allow recovery

Correct Answer:Food chain,Shows who eats what in a group of living things

Shows who eats what in a group of living things

Correct Answer:Ocean acidification,When seawater absorbs excess carbon dioxide (CO₂)

When seawater absorbs excess carbon dioxide (CO₂)

Q2.
What causes ocean acidification?

Oil spills in the sea
Chemicals from farming washing into the sea
Correct answer: CO₂ being absorbed from the air
Plastic pollution in the water

Q3.
A student says, "Ocean acidification is caused by pollution from land." What’s a better explanation?

Correct answer: It results from CO₂ absorbed from the air
It’s caused by water mixing with plastic
It happens when oil spills enter the sea
It’s due to farm chemicals washing into the sea

Q4.
What might happen if smaller fish are removed from a food chain?

Larger fish increase in number
Nothing changes
Coral reefs grow faster
Correct answer: Predators lose their food source