Unit 8 - Essays - Coral Reefs - SIMPLE ENGLISH UPDATED Flashcards
To What Extent Can the Threats to Coral Reefs Be Successfully Managed?
- Climate Change and Coral Bleaching: The Biggest Threat
What is the problem?
Climate change makes the ocean warmer.
When the ocean gets too hot, corals turn white (bleaching) and can die.
In 2016, 2017, and 2020, 60% of the GBR was damaged by bleaching (Great Barrier Reef Marine Park Authority, 2021).
Scientists say that if the world gets 1.5°C warmer, 90% of all coral reefs could disappear (IPCC).
What is being done?
The Australian government wants to stop producing extra carbon emissions by 2050.
Cloud brightening (spraying salt into clouds) is being tested to cool ocean temperatures.
Is it working?
These efforts help a little, but they do not solve the problem.
Climate change is a global problem, so even if Australia acts, other countries still need to do the same.
Judgment:
We cannot stop climate change just by protecting the GBR locally. The only real solution is for the whole world to reduce emissions.
- Pollution from Farms and Cities: A Manageable Problem
What is the problem?
Fertilizers and pesticides from farms wash into the ocean when it rains.
This pollution causes algae to grow too much, covering corals and blocking sunlight.
Pollution also increases outbreaks of Crown-of-Thorns Starfish (COTS), which eat corals.
Over 80% of the GBR’s pollution comes from farming.
What is being done?
The Reef 2050 Plan aims to cut nitrogen pollution by 60% and sediment by 25% by 2025.
Farmers are being encouraged to use less harmful fertilizers and plant trees to stop runoff.
Is it working?
So far, nitrogen pollution has only been reduced by 25% (Australian Institute of Marine Science, 2023).
Some areas are doing well, but others still have a lot of pollution.
Judgment:
This problem can be controlled, but progress is slow. More rules and better enforcement are needed.
- Overfishing and Marine Protected Areas (MPAs): A Local Success
What is the problem?
People catch too many fish, including species that help keep corals healthy.
Without fish like parrotfish, algae grow too much and smother corals.
What is being done?
Australia has set up Marine Protected Areas (MPAs) in the GBR, covering 344,400 km².
33% of the reef is a no-fishing zone.
Fish numbers in MPAs are 50% higher than in areas where fishing is allowed (GBRMPA, 2022).
Is it working?
MPAs work well in protected areas, but:
Illegal fishing still happens, especially in remote places.
MPAs cannot stop climate change, so reefs are still under threat.
Judgment:
MPAs are very effective locally. However, they only fix one part of the problem—they don’t protect against rising temperatures.
- Tourism and Coastal Development: A Mixed Success
What is the problem?
The GBR brings in $6.4 billion per year from tourism and supports 64,000 jobs.
But too many visitors can harm reefs by:
Trampling corals while snorkeling and diving.
Dropping boat anchors on reefs.
Pollution from hotels and boats.
Coastal development, like the Abbot Point coal terminal, can cause pollution and sediment to spread into the reef.
What is being done?
Tourism regulations limit the number of visitors to sensitive areas.
85% of tourism businesses now follow eco-friendly practices.
Some developments are stopped, but big businesses push for more expansion.
Is it working?
Tourism can be controlled, but coastal development is harder to stop.
Some parts of the GBR, like Cairns and the Whitsundays, suffer more damage because they have more tourists.
Judgment:
Tourism management is successful, but stopping harmful coastal development is more difficult because of economic pressure.
- Coral Restoration: A Short-Term Fix
What is the problem?
Many reefs are already damaged, and some may not recover naturally.
Scientists are testing ways to help reefs regrow, including:
Coral nurseries (growing corals in safe environments and transplanting them).
Artificial reefs.
Heat-resistant corals (breeding corals that can survive in warmer oceans).
What is being done?
The Australian government has invested $150 million in restoration projects.
Some heat-resistant coral trials show a 75% survival rate in controlled conditions (Australian Institute of Marine Science, 2023).
Is it working?
These efforts help small areas, but:
The GBR is 2,300 km long, so restoring the whole reef is impossible.
Restoration cannot stop climate change—it only buys time.
Judgment:
Restoration is helpful, but it is not a long-term solution. We still need to stop the main causes of reef damage.
Conclusion
Some threats to the GBR can be managed, but others are much harder to control.
Local actions like MPAs, pollution control, and tourism management help protect reefs, but they do not stop the biggest threat—climate change.
Coral restoration offers hope, but it is too expensive and small-scale to save the whole reef.
The future of coral reefs depends on global action to reduce carbon emissions.
Final judgment: Local efforts can help, but they are not enough to fully protect reefs. Only global climate action can ensure coral reefs survive for future generations.
Assess the significance of different threats to coral reefs.
- Global warming and coral bleaching – The biggest threat
What’s happening:
The sea is getting hotter because of climate change
Coral gets stressed by heat and loses its colour – this is called bleaching
Bleached coral becomes weak and can die
Real example:
In 2016, 91% of reefs in the north part of the GBR were bleached
There have been 5 major bleaching events since 1998
Why this is serious:
It affects almost the whole reef
It keeps happening more often, so coral doesn’t have time to recover
This is hard to fix and makes other problems worse too
How long and where:
Happening now, and getting worse
Affects the entire reef
- Ocean acidification – A slow but dangerous problem
What’s happening:
The sea is absorbing more carbon dioxide (CO₂) from the air
This makes the water more acidic (lower pH)
Coral can’t grow properly in acidic water
Real example:
The sea has become 30% more acidic since the 1800s
Coral in the GBR is growing 14% slower than in 1990
Why this is serious:
The coral becomes weaker and breaks more easily
It affects coral everywhere in the reef
It’s hard to stop and takes a long time to fix
How long and where:
Happens slowly, but the damage lasts a long time
Affects the whole reef
- Sea level rise – A growing problem in some areas
What’s happening:
The sea is rising because of melting ice and warming oceans
Coral that is too deep can’t get enough sunlight
Rising sea levels can also bring more mud and sand (sediment) into the water
Real example:
The IPCC says the sea could rise by up to 1 metre by the year 2100
The Burdekin River near the GBR brings in a lot of sediment after rain
Why this is serious:
Muddy water blocks sunlight and smothers coral
This mostly affects reefs near the land
It makes coral weaker, especially in inshore (near land) areas
How long and where:
Happens slowly over time
Mostly affects coastal areas, not far-out reefs
- Pollution from farming – A big problem near the coast
What’s happening:
Farms use fertilisers and chemicals
Rain washes these into rivers, and the rivers carry them to the reef
Too many nutrients cause algae to grow and cover coral
Real example:
Only 2% of sugarcane farms near the reef use the best farming methods
Rivers like the Fitzroy and Burdekin carry most of the sediment and nutrients
Why this is serious:
Algae takes over the coral’s space
Coral can’t breathe properly or get sunlight
Pesticides can poison sea animals
How long and where:
Problem is ongoing (keeps happening)
Mostly affects reefs close to rivers and farms
Good news:
This can be reduced with better farm practices
- Physical damage from tourism and fishing – A local problem
What’s happening:
Boats and tourists can break coral by stepping on it or anchoring
Fishing can damage coral or take too many fish that help the reef
Real example:
Over 2 million tourists visit the GBR each year
Areas like the Whitsundays are most affected
Why this is serious:
Broken coral grows back slowly
Overfishing lets algae grow too much
Turtles and dugongs can get hurt by boats
How long and where:
Happens in busy areas
Damage is local and short-term, but can build up over time
Good news:
Rules and education can help reduce this
CONCLUSION
What to say:
Many things are harming coral reefs, but climate change (warming and acidification) is the most serious
These threats affect the whole reef, and the damage is long-lasting and hard to stop
Pollution and human damage are still important but easier to manage with local actions
We need local and global action to save the reef
‘The characteristics and formation of fringing reefs, barrier reefs, and atolls are very different.’ How far do you agree with this view?
Paragraph 1: Fringing Reefs – What they look like and how they form
What they look like:
Fringing reefs grow next to the land (very close to the shore).
There is no deep lagoon between the reef and the land.
They are narrow and simple in shape.
How they form:
Coral starts growing in shallow water near the shore.
Over time, it grows outwards toward the sea.
Fringing reefs don’t need sea level to change.
They are the first stage in how some reefs grow over time.
Examples:
Found in Indonesia, Philippines, and Caribbean.
Why they are different:
Simple, small, and fast to form compared to the other reef types.
Paragraph 2: Barrier Reefs – What they look like and how they form
What they look like:
Barrier reefs are further away from the coast than fringing reefs.
There is a wide, deep lagoon between the reef and the land.
They are very large and can stretch for thousands of kilometres.
How they form:
They start as fringing reefs.
If the land sinks or the sea level rises, the reef keeps growing up.
This creates a lagoon between the reef and the land.
Case study: Great Barrier Reef
2,300 km long and has 2,900 small reefs.
Found 60 to 250 km off the coast of Australia.
Started forming 500,000 years ago; modern structure about 6,000–8,000 years old.
Very biodiverse: 1,500 species of fish, 400 types of coral.
Why they are different:
Much bigger, take longer to form, and need changes in sea level or land.
Paragraph 3: Atolls – What they look like and how they form
What they look like:
Atolls are ring-shaped reefs with a lagoon in the middle.
There is no land in the centre—just water.
How they form:
Start as a fringing reef around a volcanic island.
The island slowly sinks, or sea level rises.
The coral keeps growing upward.
Eventually, the island is completely underwater, leaving a ring of coral.
Examples:
Bikini Atoll in the Marshall Islands
Maldives
Why they are different:
Very old, take millions of years to form, and need a sinking island.
Easily damaged by sea level rise and storms.
Paragraph 4: Similarities between all three types
Same environmental needs:
All need:
Warm water (23–29°C)
Shallow depths (less than 50 metres)
Clear water for sunlight
Stable salt levels
Same way of forming:
Made by coral polyps, which build hard skeletons.
Coral grows at 1–10 mm per year.
Coral depends on light, temperature, and low sediment.
Same benefits:
All support sea life.
The Great Barrier Reef has huge biodiversity—fish, coral, turtles, and more.
So…
Even though they look different, all reef types grow in similar places and need the same conditions to survive.
Paragraph 5: Scientific theories that explain how reefs form
Darwin-Dana Theory:
Coral reefs grow in a sequence:
Fringing reef
Barrier reef
Atoll
Happens as the land slowly sinks.
Shows how reef types might be connected over time.
Murray’s Theory:
Coral bits break off and build up on the seaward side.
Reefs grow outward, not just upward.
Does not need land to sink.
Daly’s Theory:
After the last ice age, sea levels rose.
Coral grew on underwater platforms (like wave-cut surfaces).
Explains how some atolls formed.
So…
These theories show some types might be linked over time.
But they also show that different processes can create similar reefs.
Conclusion (Clear judgement)
Fringing, barrier, and atoll reefs are very different in their shape, location, and how they form.
The Great Barrier Reef shows how complex and huge barrier reefs can be.
But all reefs grow in similar tropical conditions and support marine life.
So, I mostly agree: they are different, but do have some things in common.
