A “Underwater Neighborhood” Bigger Than Germany#
Off the northeast coast of Australia, there’s a massive “underwater neighborhood.”
How big is it? 340,000 square kilometers — bigger than all of Germany!
It’s the Great Barrier Reef, the largest coral reef system in the world.
If you stretched it out straight, it would be 2,300 kilometers long — farther than from Beijing to Guangzhou.
Coral: Tiny Animals That “Build Houses”#
What are the “building materials” of the Great Barrier Reef? Coral.
Coral looks like rock, but it’s actually a living animal!
Coral polyps are only a few millimeters big — smaller than your fingernail. But they have an amazing skill: they can build houses.
Coral polyps absorb calcium from seawater and use it to build hard shells. Generation after generation of coral polyps spent thousands of years “building” the Great Barrier Reef.
The coral reefs you see are actually the “homes” of countless generations of coral polyps stacked together.
A “Party” of 1,500 Fish Species#
The Great Barrier Reef is like a giant “underwater party,” home to over 1,500 species of fish.
There are colorful clownfish (that’s Nemo from “Finding Nemo”), massive whale sharks, “flying” manta rays, and color-changing octopuses.
Besides fish, there are 400 types of coral, 4,000 species of mollusks, 240 species of birds…
This is one of the most biodiverse places on Earth.
The Reef’s Crisis: Coral Bleaching#
But the Great Barrier Reef is getting sick.
Because of global warming, rising sea temperatures are “heating” the symbiotic algae out of the coral. Without the algae, the coral loses its color and turns white — this is coral bleaching.
Bleached coral doesn’t die immediately, but if the water temperature doesn’t come back down, it will eventually die.
In the past 30 years, the Great Barrier Reef has experienced multiple mass bleaching events. Scientists say that if global warming isn’t controlled, the reef could disappear within decades.
Learn from the World#
The Great Barrier Reef teaches us one thing: even the most powerful ecosystems are fragile.
The reef has existed for thousands of years, but it took only a few decades to start declining.
Protecting the environment isn’t just an empty phrase — it’s the responsibility of every one of us.
Knowledge Card#
- Location: Northeast coast of Queensland, Australia
- Type: Natural Wonder
- Key Numbers: 340,000 sq km area, 2,300 km long, about 2,900 individual reefs
- Biodiversity: 1,500 fish species, 400 coral types, 4,000 mollusk species
- Fun Fact: The Great Barrier Reef is the only living structure visible from space with the naked eye
- UNESCO: Listed as a World Heritage Site in 1981
- Source: Great Barrier Reef Marine Park Authority