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Place 01 · The Great Barrier Reef · Wrap-up
What a Reef Is Worth
You came for the fish. You are leaving with chemistry, and a number with a lot of zeros on it.
About 20 minutes · 1 video · a full practice review of the whole reef
Look back
Seven chapters ago you did not know any of this
You can now
Explain where reefs live
And why the answer is about a tilted planet and the angle of sunlight, not about corals simply liking warm water.
You can now
Say what a reef is made of
Carbon from the air, pulled out of seawater by an animal, with the energy bill paid by algae living inside it.
You can now
Tell two threats apart
Heat drives the algae out. Chemistry takes away the building material. Different problems, different fixes.
Photos: Asad Photo Maldives, hartono subagio, mingche lee / Pexels
One more thing
The number nobody expects
Reef Resilience Symposium — Tourism Stewardship on the Great Barrier Reef. The people whose jobs depend on the reef, and what they are doing to protect it.
What the reef is worth
- About AU$95 billion in total value to Australia
- About AU$9 billion added to the economy in a single year
- Roughly 77,000 full-time jobs
- Nearly 90% of it is tourism: people paying to look
All of it rests on a chemical balance and a thermostat. That is not a figure of speech. It is the supply chain.
Figures: Great Barrier Reef Foundation, At What Cost?, October 2025 (2023–24 data).
Where you can see it for yourself
Whitehaven Beach, and the reef beyond it
Put it all together
Reef Review
Seven chapters, one reef. This review walks the whole place, from the polyp to the price tag, with a few questions that tie chapters together. Retry as often as you like. If one trips you up, the feedback names the chapter to revisit, and every chapter has its own eight-question practice set at the bottom of the page.
Practice
Reef Review: the whole place
Twenty questions covering all seven chapters and this page. Aim for a clean run, then you are ready to leave the reef.
Where we go next
Place 02 is colder, and the wind is doing it
A bay in California is colder in summer than the sea off Maine, hundreds of miles farther north, and richer than almost any water on Earth. Same ocean, a warmer latitude, and still the colder answer. You will need everything you just learned about light and temperature to work out why.
Photo credits (Pexels): Mo Ismail, Thomas, jermeen john.
Hop to:
← The Great Barrier Reef — place overview
All Places
- The Great Barrier Reef
- Monterey Bay
- The Galápagos
- The Ridge and the Trench — in development
- The Southern Ocean — in development
- The North Pacific Garbage Patch — in development