Why are coral reefs so important?

Coral reefs are home to many unique animals and plants that could not survive anywhere else. Tens of thousands of plant and animal species live in coral reef areas. Coral is very important ic controlling how much carbon dioxide is in the oceans. Without coral, the amount of carbon dioxide in the water would rise dramatically, which would affect all living things on Earth. Coral reefs also protect coastlines from strong currents and waves by slowing the water down before it reaches the shore. That's why they are called barrier reefs.

adapted from: On the job- Sea life scientist-Have you got what it takes to be a marine biologist? by Lisa Thompson

Humans helping corals, corals helping humans

Marine biologists may have found a new form of first aid for injured coral reefs. Reseachers at the University of Guam have managed to grow 10 species of coral. They hope this will lead to the "farming" of coral by aquarium suppliers. Live patches of farmed coral could be applied to reefs that have been damaged, helping the reefs to regenerate. Someday, there even could be a bank of corals to be transplanted into damaged reefs all over the world.

Coral help humans in many ways, and some of those ways are personal. Corals, for example, can be used to make medicines. Australian scientists have developed a sunscreen from substances in corals. The corals use the substances to protect themselves from the sun's ultraviolet rays. It has an SPF(sun protection factor)of more than 50. Even animals that live in the coral help humans. Scientists in the United States have created a potent pain-killing drug from the poison of reef-dwelling sea snails.

adapted from: On the job- Sea life scientist-Have you got what it takes to be a marine biologist? by Lisa Thompson

Reef types

There are three kinds of coral reefs: fringing rees, barrier reefs, and atolls.

• Fringing reefs grow right up to the shore.



• Barrier reefs are seperated from the shore by a wide, deep lagoon.



• Atolls are coral reefs that surround a shallow lagoon. They are created when an island that is surrounded by barrier reefs sinks below the water, leaving a cicular reef, the atoll.

Why is there so many crown-of-thorns starfishes?

Why do crown-of-thorns starfish numbers get out of hand? No one knows the answer yet, but one theory is that the runoff from chemicals that are used in farming is allowing more starfish eggs to survive. Another reason could be that the main predator of the crown-of-thorns starfish which is the giant triton(a large sea snail), has been hunted extensively by humans. The giant triton's shell is a popular souvenir.

adapted from: On the job- Sea life scientist-Have you got what it takes to be a marine biologist? by Lisa Thompson

The Four Big Threats to Coral Reefs

1. Coral diseases
Scientists believe that runoff nutrients and sediment from the land, as well as high sea temperatures in summer, can cause coral diseases. There are about 30 known coral diseases, and the Great Barrier Reef has at least six of them. They include black-band disease, white syndrome, and coral tumours. Coral diseases are carried and spread by bacteria, fungi, algae, and worms.

2.Coral bleaching (as shown in the previous post)

3.Crown-of thorns starfish
Small numbers of this starfish on a reef are normal. They are simply part of the coral reef ecosystem. In large numbers, they eat corals faster than corals can grow and reproduce. A crown-of thorns starfish eats an area of coralthe same size as itself in a single day. In one year, one of these starfish can destroy 6 square yards of coral. If there are hundreds of them on a reef, it means destruction of the reef

4.Humanity
People damage coral reefs in three main ways- through pollution, tourism, and fishing.
Not all coral reefs around the world are as healthy as the Great Barrier Reef. Since 2000, almost 30% of the world's reefs have been destroyed. It is estimated that 11% have been lost because of humans, through pollution, overfishing, dynamite fishing, minig of sand, or onshore building and development. Scientists think that two of every three reefs could disappear in the next 40 years! We need to protect and preserve these rain forests of the sea.

adapted from: On the job- Sea life scientist-Have you got what it takes to be a marine biologist? by Lisa Thompson

Corals in Singapore

Singapore reefs are found around islands south of the mainland, like Sentosa, Pulau Hantu, The Sisters, Pulau Satumu and many others. Despite being whithin one of the world's busiest ports,Singapore's reefs still support rich biological communities.

Global Warming and coral reefs

The world is getting warmer. Coral bleaching occurred in almost all tropical oceans as far back as 1997. Reef areas in the Maldives, Sri Lanka, Kenya, Tanzania, and the Seychelles have been greatly affected by bleaching.

In 2002,the worst bleaching ever recorded occurred in the Great Barrier Reef. It affected 60 percent of surveyed reefs,and the damage was very severe in some areas. Most reefs survived, but full recovery of badly damaged reefs may take decades.


adapted from: Sea life scientist-Have you got what it takes to be a marine biologist.

coral bleaching

Coral reefs are sentitive to temperature, needing water that is never cooler than about 20 degree celcius and never warmer than 29 degree celcius. Bleaching of coral reefs has occured due to locally rising sea temperatures, thought to be caused by climate changes brought about by El Nino. These sensitive organisms die in water that is too warm - a rise of only one or two degrees is enough to start the bleaching process. The algae that live inside the polyp die, and the remaining polyp turns white and also dies. By the late 1990s, it was thought that more than half of the Great Barrier Reef had been affected by bleaching.

adapted by: caring for the planet-seas and oceans, by Neil Champion

Coral polyp

The polyp is supported in a stone-like cup. It makes the cup from substances dissolved in seawater. The cup, called a theca, anchors the polyp to the older layers below and to the polyps around it.
The tentacles catch food, although the coral gets most of its food from tiny single-celled plants that live inside the coral tissues.

adapted from: How it works- Exploring The Oceans, by Stephen Hall

Animals that use the corals to protect themselves

There are many different animals that use coral reefs to camouflage themselves to hide from their enemies or predators. Blending perfectly with the backdrop of sponges and corals, the scorpion fish waits for its prey, such as small fishes and crustaceans. The purple stonefish matches the coral-covered rocks on the sea floor. The pipefish has adapted its shape and colour to match the kelp and coral that grow under the sea. The red-and-white hawkfish camouflages itself by darting in and out of red branched corals.

adpted from: Time Warner discoveries library- Under the Sea

How coral atolls form

A coral reef starts to grow around a volcanic island. The volcano becomes inactive and erodes away or sinks while the reef keeps growing. When the islandhas sunk completely, the reef appears a ring- or horseshoe-shaped from above. It has a shallow lagoon in the middle.

adapted from: How It Works- Exporing the OCEANS, by Stephen Hall

The brain coral

The brain coral looks exactly like a human brain except that it is much larger. It grows slowly and have annual growth rings like a tree.

Corals in danger

Coral reefs are being damaged all over the world. Coral reefs grow very slowly, so every reef that is destroyed will take another hundred years to grow. Corals are like forests,we take corals to make things like necklaces. Some fishermen use poison to catch tropical fishes from the reefs which are then sold to pet shops. Careless divers are also responsible for damaging these beautiful corals.

The Great Barrier Reef

The Great Barrier Reef Marine Park is the largest sanctuaries in the world. It extends for 2,000 km(1,240 miles) along the coast of northeastern coast of Australia. The Great Barrier Reef is made up of 2900 separate reefs. the coral reefs boasts a diversity of species rivaled in number only by the diversity found in tropical rain forest.

adapted from: Time Warner discoveries library- Under the Sea and sea life scientist-Have you got what it takes to be a marine biologist? By Lisa Thompson.

Marine Parks

Coral reefs are breaking down all over the world from the effects of pollution and overfishing. To prevent this, most tropical coutries are creating marine parks to help protect coral areas from further damage. Tourists can enjoy the reefs and the fishes at these parks.

adapted from: Time Warner discoveries library- Under the Sea

Coral types and communities

There are more than 500 species of coral, such as sea fan coral, hard brain coral, bubble coral, mushroom coral, staghorn coral and soft fire coral, grow together. They have a wide range of shapes, sizes and colours, yet they all have the same basic body plan- a simple sacklike stomach and a mouth that is surrounded by a ring of poison filled tentacles. They live side by side with goldfish, giant clams, surgeonfish and many other sea dwellers.


adapted from: Time Warner discoveries library- Under the Sea

the home to many living things

Corals are home to many different types of animals. Crutaceans, sea urchins , molluscs, clams and some fishes are some of them. Clownfishes lives and hides from its enemies and predators within the tentacles of the coral reef anemone. It escapes being stung by covering itself in a layer of mucus from the anemone. The anemone is fooled into thinking the the fish is part of itself.

adapted fom: Time Warner discoveries library- Under the Sea

How corals get their food

Each polyp has many round plant cells living in its body and these cells photosynthesises. the corals are able to catch their own food with their stinging tentacles, but most of the food is made by the plant cells. Coral reefs need th efood from these plant cells to grow quickly.


adapted fom: Time Warner discoveries library- Under the Sea

How coral reefs are formed

These marine homes grow in warm shallow seas and are built by coral animals, or polyps, with softbodies and mouths that are ringed by stinging tentacles. The polyps construct thimble-shaped skeletons of lime stone around themselves. As the polyps grow upwards, they keep dividing in two. They leave their skeletons behind them, however, and fuse together to make coral reef.



adapted from: Time Warner discoveries library- Under the Sea