Coral Reefs

A colorful reef with different types of coral depicted against a deep blue background of ocean.  Tiny fish swim amongst the coral’s branches.

Coral reefs are a type of ecosystem.  For more than 400 million years, corals have been building reefs in the earth’s oceans.  Corals may look like plants, but they are actually animals!  Coral is made from polyps that grow in fantastic ways.  When they die, their skeletons remain, and become a hard rock base for new polyps to grow on top of.  Coral animals grow in all sorts of different ways.  Some form branches like the antlers of a deer.  Some make huge mounds that look like giant brains.  Others grow in the shape of mushrooms.  Coral reefs are mostly found in shallow, clear, tropical waters.  

Unfortunately, coral reefs are in danger!  Because of man-made problems like overfishing, plastic pollution, rising global temperatures, and coastal developments, coral reefs are starting to die.  The coral is starting to bleach, which means it is losing all of the vibrant colors that make it so beautiful.  The bleached coral, and rising acidification in the water mean that the plants and other animals in the ecosystem are dying too.  Scientists worry that all of the coral reefs in the world could be gone by the year 2050.

An orange and white clownfish swims in front of coral of different kinds and colors.
The Scott Reef in 2016 after a bleaching event.  The coral is white, and has a few fish swimming around it.
Did You Know?
  • Coral reefs are home to a wide variety of marine life, including plants, fish, and reptiles.  Coral reefs are among the most diverse ecosystems on earth.
  • Although the total area covered by coral reefs is less that 0.015% of earth’s oceans, coral reefs are home to about one quarter of the planet’s marine life.
  • The largest coral reef in the world is off the east coast of Australia.  It is called the Great Barrier Reef.  It is about 1,430 miles long, and is so big that astronauts can see it from space!
  • There are different types of coral reefs.  The three main kinds are Fringing Reefs, Barrier Reefs, and Atolls.  
  • Some types of animals that you can find living in a coral reef are raccoon butterflyfish, cone snails, tube sponges, spiny row coral, sea slugs, giant clams, sea whip coral, redtooth triggerfish, half-and-half goatfish, staghorn coral, sea anemone, clownfish (like Nemo!), star coral, crown of thorns starfish, sea fan coral, pincushion urchin, fungus coral, bubble coral, and many, many more.