Ranger Rick Reefs December January 2016

Ready-Made Reefs

By Kathy Kranking

There’s more to some coral reefs than meets the eye.

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Check out this beautiful coral reef. What colorful corals and fishes! Now look at the reef more closely. Why does it have watery windows and a doorway? Because the corals and fishes are “all aboard” a sunken ship!

The ship is now a human-made reef. Normally, reefs are built by corals, which are tiny animals. Each coral builds a stony cup around itself. As corals die, other corals build cups on top of them. The cups keep piling up to form a reef. But that can take hundreds of years. So to help make new reefs more quickly, people sink old ships, train cars, and certain other things in shallow ocean water. That provides ready-made places for corals to grow.

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A coral reef is like a colorful neighborhood where corals, sponges, anemones (uh-NEM-uh-nees), fishes, crabs, shrimps, and many other kinds of creatures live. It’s a place where they find food, take shelter, and have their young.

But coral reefs are in trouble. Because of problems such as pollution and climate change, almost one-fifth of the world’s coral reefs have died.

So people have been doing something to help. Instead of leaving things such as old train cars and ships to rust away in junkyards, they clean them up and sink them in the ocean. Corals, sponges, and algae (AL-jee) grow on them. Then fishes and other coral reef creatures move in.

Natural reefs have lots of nooks and crannies to hide in. But this human-made cement reef has hiding places, too. Reef dwellers such as the moray eel seem as happy in this reef as in a natural one. To them, a reef is a reef!

It looks as if these corals are climbing on a jungle gym! This human-made reef has a twist: A very weak amount of electricity runs through it. The electricity (which comes from cables from shore) causes minerals in the water to form a crusty coating on the reef. The coating is a good base for corals to grow on. Pieces of broken coral from other reefs can then be “transplanted” here.

Check out this artificial reef off an island in Australia. It’s made of 15 ships that were sunk here more than 50 years ago (bottom of photo). Today the reef is a popular place for people who scuba dive and snorkel to see beautiful fishes and corals.

In some places, people have made sculptures to put on the sea floor to become reefs. The sculptures are often made of a special cement that coral grows on easily. After several years, this statue will be completely covered up.

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Not all artificial reef structures were put into the ocean on purpose. Some, such as ships wrecked in storms and sunken during wars, got there accidentally. This nurse shark is resting in what’s left of an old sailing ship that sank years ago.

The big gun below came from the deck of a ship sunk during World War II. Now it’s a living work of art, covered with beautiful corals, sponges, and anemones. Even an old toilet can become a reef (right).

Coral reef creatures find everything they need on a reef—even an artificial one. This sea turtle is snacking on red corals inside the skeleton of an old shipwreck.

As you’ve probably figured out by now, just about anything can become a ready-made reef!


“Ready-Made Reefs” originally appeared in the December/January 2016 issue of Ranger Rick magazine.
(Click on each image above for a closer view of the story.)

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