Coral reefs are rocklike ridges that
form in warm ocean water. Coral are
not actually rocks. They are animals
with rocklike skeletons. They live
together in large groups called
colonies. Many other animals and
plants make their homes on or near
coral reefs.
The best-known
coral reef
is the Great Barrier Reef. It is off
the coast of northeastern Australia.
More than 3,000 smaller reefs make
up this huge ecosystem. The Great
Barrier Reef stretches more than
1,243 miles (2,000 km) along the
coastline. It can be seen from outer
space. This ecosystem is home to
sharks, sea turtles, and more than
30 types of marine mammals,
such as dolphins.
Many marine
species live in a coral
colony in Koh Tao,
Thailand.
Coral Reefs Are
Diverse Ecosystems
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