Filled with Life Combined the world’s reefs cover less than 1 percent of the sea floor Yet they have a huge amount of biodiversity This means many kinds of plants and animals live there One third of the world’s ocean fish species spend part of their lives in coral reefs 6 Everything in the reef plays an important role in this ecosystem Courtney’s diving instructor told her to be watchful Dangerous animals live among the beautiful corals A painful jellyfish sting could quickly ruin the day She hoped to see other marine life though Even a short glimpse of a sea turtle would be thrilling The Keys are home to about 1,700 species of mollusks and 500 species of fish With such a variety of life this amazing ecosystem is as diverse as it is beautiful What Is a Coral Reef A coral reef is an underwater ecosystem It is made up of plants fish and other living things The organisms of a coral reef live on the hard
The reefs of the Florida Keys are near the shoreline skeletons of coral Corals are tiny animals that live in huge groups or colonies The structures they build are known as reefs Each plant and animal of the reef has a function within the ecosystem There are three types of coral reefs Fringing reefs are the most common They begin at the fringe or edge of a shoreline and extend into the sea These reefs create a border along coasts Many fringing reefs are found in the Caribbean Sea 7
8 A Coral Reef Food Web Many plant and animal species make up a coral reef ecosystem Each one depends on the other species for its survival This complex network of living things is called a food web The arrows show the movement of energy through the web The sun provides energy for algae and sea grass to grow Parrot fish feed on both coral and algae The fish are hunted by lemon sharks Manatees eat the sea grass
Corals Corals are invertebrates This means they do not have backbones These tiny animals are related to jellyfish A single coral is called a polyp It has a stomach that opens at one end Its mouth is surrounded by tentacles The tentacles help the polyp capture smaller animals as food Tiny creatures called algae live inside corals The algae turn the sun’s light into more food for the corals 9 Barrier reefs also create a border between land and the open ocean They are much farther from the land than fringing reefs however A deep lagoon fills the space between a barrier reef and land Australia’s Great Barrier Reef is one of the world’s best-known barrier reefs Atoll reefs may have no land near them at all These reefs formed around volcanic islands The islands later sank below the water’s surface But the reefs continued to grow upward Sometimes there is a small piece of exposed land within an atoll coral reef Wake Island in the Pacific Ocean has an atoll reef
