An atoll is a small island shaped like a ring or horseshoe, found in the warm waters of tropical seas. Inside the ring there is water, called a lagoon. The ring is made of the skeletons of millions upon millions of tiny sea creatures called coral. These creatures live together in huge colonies.
An atoll is a small island
shaped like a ring or horseshoe, found in the warm waters of tropical
seas. Inside the ring there is water, called a lagoon. The ring is
made of the skeletons of millions upon millions of tiny sea creatures
called coral. These creatures live together in huge colonies. They
live where the water is less than 510 feet deep, because they need
sunlight, which cannot reach very far into deep water. Coral like to
live in waters that arcclose to the shores of an island.
After thousands of years
the skeletons of dead coral form a rock wall like a ring around the
island. Then suppose an earthquake causes the island to settle below
the water. The coral ring remains, and is an atoll. Dirt, pieces of
wood, mud, and other rubbish are washed over the rough coral rock by
the waves, and in time soil is formed over the rock. Seeds carried
for miles by the ocean winds will drop on this soil and certain kinds
of palm trees and other plants will grow on the atoll. Sometimes the
waves will break off pieces of the top of the ring or wash away a
large section of it so that the atoll has the shape of a horseshoe
above the water. The water of the lagoon inside the ring is never
very deep. There are many atolls in the South Pacific Ocean.
