Coral Reefs

By Alex Warren

Contents Photos

How a coral reef is madeAreas of a reef

Coral Reef Locations

Types of coral reefsTypes of coral

AnimalsInvertebrates

The Great Barrier Reef Artificial reefs

ThreatsMy thoughts on coral reefs

Acknowledgements

Photos

How a coral reef is madeThe world's first coral reefs were created about 500 million years ago.Most coral reefs are formed when a volcanic island goes extinct.When the ocean and the island floor collapses, coral growth makes a fringing reef, often creating a shallow lagoon.As the volcanic island continues to collapse, the fringing reef turns into a barrier reef, further away from the land with a bigger and deeper lagoon inside.In the end the island sinks and the barrier reef turns into an atoll reef , enclosing an open lagoon.Reefs are built by coral . The coral is formed when loads of living organisms know as polyps, join together then die and more grow on top of each other then die and so on and so on …

Diagram of a polyp

Areas of a reef

There are several areas of a coral reef these are:The reef surfaceThe reef surface is the shallowest part of a Coral reef. The waves pass over the shallow water and the coral here is most affected by the tides. The off reef shoreThe off reef shore is the floor surrounding a reefthis zone occurs on continental shelves. The drop offThe first 50 meters of the drop off provides a habitat for fish and plankton.

Areas of a reef

The reef faceThe reef face is above the reef floor or the drop off. Its usually the richest area of the reef with the most species of coral.The reef flats

The reef flats are at the bottom of the reef. The reef flats has the most species of fish.The reef lagoonA reef lagoon is where many of the coral reefs are constantly changing, they usually contain small patches of coral.

Coral Reef Locations

This map shows coral reef locations throughout the world.

Types of Coral Reefs

Here are a few types of coral reefsCays: cays are islands in the middle of coral reefs.Atoll reefs: an atoll reef is a circular barrier reef.Fringing reef: this is a coral reef that’s attached to the shore.Barrier reef: a reef separated from the land by a lagoon.Apron reef: a long narrow reef usually connected with a lagoon.

Cay reef Atoll reef

Types of coral

Brain coral Leaf coral

Table coral Pillars coral

Antlers coral Christmas tree coral

AnimalsLoads of animals live in or near a coral reef.Here are a few examples:Some fish that live in a coral reef can be as colourful as the reef, like the parrot fish and the damsel fish. At night-time some fish change to a darker colour to hide from predators. Coral reefs provide habitats for some endangered birds.Midway atoll in Hawaii supports nearly 3 million sea birds including 1.5 million of the global population of the Laysan Albatross, and 1/3 of the global population of the Black Footed Albatross.

AnimalsOther animals include the Jellyfish and the Seahorses.Types of Seahorse include the Long Snout Seahorse. Seahorses are the only species where the male gives birth to live young.Also in the reef there are Whales, Dolphins and SharksTypes of sharks include the White Tip Reef Shark.Dolphin types include the pacific Humpback Dolphin and the Bottled Nosed Dolphin.Whales include the Humpback Whale.

White Tip Reef SharkHumpback whale

Invertebrates

Examples of Starfish include Crown Of Thorns and the Blue Starfish.

Examples of Flatworms include the Reef Dwelling Flatworm and the Christmas Tree worm.

Examples of Jellyfish include the Box and Moon Jellyfish.

Examples of Squids include the Caribbean Reef Squid.

Invertebrates are animals without a spine, like Starfish, Flatworms, Jellyfish and Squids.

The Great Barrier ReefIn the tropical costal waters of Northeastern Australia is the Great Barrier Reef.The Great Barrier Reef is actually around 2900 separate reefs and 1000 islands. The reef is so big it can be seen from space.The Great Barrier reef is the largest coral system in the world.It stretches approximately 1,250 miles(2,011km)along the Australian coast from Lady Elliot island to the Cape of York. Types of animals that live on the reef include 1,500 different fish species, 4000 species of mollusks, more than 400 types of coral and 30 species of Whales, Sharks and Dolphins.

ThreatsThere are a lot of threats to a coral reef. Here are a few.

Crown Of ThornsCrown Of Thorns are a type of starfish that eats polyps that make coral reefs. If a Crown Of Thorns stays on a reef for too long it could kill the reef.

Dynamite fishingDynamite fishing is also a problem because people throw dynamite into a reef and when it blows up it kills the fish and they float to the top, but also blast away pieces of coral.

TourismTourism can be a problem because people could stand on the coral or swim up to the fish and touch them. This could bring diseases and pollution to the water. Divers could also damage coral by moving against it and snapping pieces of coral reefs off to take home as a souvenir. The boats could also pollute the water.

Threats part 2Climate change Climate change can be a problem because the water could get too warm or too cold and the coral could die.

Algae Algae can also be a threat pollution and extra nutrients washed over the reef helps algae to over take and kill the coral.Around some pacific islands algae covers a large percentage of coral

FishingFishing is another problem to coral reefs because their nets and anchors can destroy the reefs, and fishing nets could drown animals that need air and water to live.

Artificial reefsArtificial reefs can be formed usually on man made items. Two examples are old shipwrecks and under oil rigs. The polyps which make the reef attach a themselves on to a man made frame on the sea bed which which they makes the artificial reef. The danger with the oil rig base is that if the rig base is removed the coral would be torn apart killing the reef.

My thoughts on coral reefsI think that coral reefs are important because they provide a habitat for hundreds of fish and coral species.I think that coral reefs are being protected well enough, but people who touch the fish or stand on the coral should be prosecuted. Also people should only dive down with an instructor or a guideCoral reefs bring economy to the local area but it also brings pollution to the area because of the boats.In the end coral reefs are important in my opinion,because of all the animal species that live there,And the benefits to the reefs and local areas out weigh the problems.

Acknowledgements

Great Barrier Reef WikipediaCoral Reefs Wikipedia

Great Barrier Reef Heritage SiteBing Images

Ocean book Bryan Richards100 Natural Wonders book

The Natural geographic dvds