Coral Reefs are the colonies created by the porous limestone skeletons of the Coral Polyps, which are tiny creatures related to the sea anemones. As the Polyps die, new ones grow over their skeletons and thus the colony extends and spreads.
Coral Polyps have sac-like bodies with a central mouth surrounded by tentacles through which ingestion and egestion of food takes place. Coral Polyps share a symbiotic relationship with the Zooxanthellae Algae that they harbor inside them and which are responsible for the colorful appearance of Coral – Zooxanthellae, with the help of Photosynthesis, provides the Polyps with much-needed Oxygen and Food while the Polyps in turn provide the Algae with the waste that they need for growth. As Sunlight is the main requirement for Photosynthetis and thereby this relationship, Coral Reefs can be found only in areas where the water is clear and transparent enough for sunlight to penetrate.
Places where Coral Reefs occur and the Different Types of Reefs :
Coral Reefs are found mainly between the Tropic of Cancer and the Tropic of Capricorn in regions where the warm sea currents occur and the usual temperatures are between 21 – 30 °C. Places where Coral Reefs are found – Eastern Coast of Africa, Southern Coast of India, Taiwan, Phillipines, Indonesia, Japan, Korea, China, the Red Sea, the North-East and North-West Australian Coasts, Polynesia, the Florida Keys, the Caribbean, Brazil, Belize.
The following four major types of Reefs are seen in these regions :
Fringing Reefs – These occur, as the name suggests, directly on the fringes of the shoreline.
Barrier reefs – These are separated from the shoreline by deep lagoons.
Atoll Reefs – These are the reefs found on the raised brims of underwater volcanoes.
Patch Reefs – These are small, unattached, and isolated formations.
The Great Barrier Reef on Australia’s North-Eastern Coast measures over 2000 kms and is the largest Reef in the World.
Importance of Coral Reefs :
Coral Reefs are called the Rainforests of the Sea. This is because they are home to an amazingly vast variety of plants and animals – some of which are even now probably not known to mankind. Aside from the environmental importance of this diverse ecosystem, Coral Reefs are of great economic interest as they provide valuable and much-needed sources of food, medicine, and other daily use products.
They also promote income sources for the Tourism Industry – Diving Tours, Shops, Hotels, Restaurants, and other such related businesses.
Coral Reefs protect the shorelines from eroding by absorbing the impact of the stronger, more destructive waves. Much of the Florida Keys would be underwater now if it weren’t for the Coral Reefs surrounding its shorelines. Reefs also provide shelters ports, harbors as well as for the economically viable coastal wetlands.
Coral Reefs absorb Carbon Dioxide from the atmosphere and help reduce Global Warming.
Creatures of the Coral Reefs :
More than 5000 varieties of Marine Creatures and 2500 varieties of Coral are found in Coral Reefs. Algae and Seagrasses are the two main types of plants found.
Some of the creatures found in the Coral Reef are – Anemones, Sponges, Blacktip Reef Sharks, Epaulette Sharks, Zebra Sharks, Octopus, Squids, Dwarf Seahorses, the Chambered Nautilus, Clown Fish, Parrot Fish, Angel Fish, Square Spot Fish, Blue Tang Fish, Scorpion Fish, Yellow-headed Jawfish, Zebra Morays, Giant Clams, Xantid Crabs, Sea Worms, Sea Urchins, Jelly fish, Oysters, Turtles, Crown-of-Thorns Starfish, Cone Snails, the Giant Triton Shell, Shrimps, Lobsters, Sea Cucumbers, and Cleaner Wrassers .
Some of the different types of Corals found are – Brain Coral, Staghorn Coral, and Elkhorn Coral, which are hard, reef-building Corals. Sea Finger and Sea Whips are soft, non-reef-building corals.
All of these organisms live in mutual interactions with one another and produce an extraordinary variety of chemicals for attracting prey, for distracting or destroying predators, for reproducing, and for numerous other purposes. Many of these chemicals can be utilized by the Pharmaceutical Industry for manufacturing new drugs to treat AIDS, Cancer, and other diseases.
Threats to the Coral Reefs :
Coral Reefs are very delicate structures and are unfortunately very susceptible to damage. If sunlight or other conditions are not favorable, the Zooxanthellae cannot photosynthesize and stand to be expelled by the stressed Coral Polyps – the polyps, in turn, cannot survive without the Zoonxanthellae and turn white as they die out. This is called bleaching. Sometimes Coral Polyps survive from effects of bleaching, but since they are extremely slow-growing organisms, it takes a very long time for the reef to recover. Sometimes, in cases of vast scale damage, there is no chance of recovery and as a result the entire ecosystem of creatures depending upon them for survival is wiped out.
Storms are especially hazardous to Coral Reefs, but in the present age Man-made dangers pose a larger and deadlier threat. Some of these are – Overfishing, Uncontrolled Coastal Development, Water Pollution, Sedimentation, Dredging, Dynamiting, Spearfishing, Oil Spills, Ship Wrecks, Boat Anchors. Diving Tourism has also not always helped matters as often many divers show little concern for the reefs or their inhabitants and destroy them by touching with hands or diving equipment. The Pet Trade for the exotic Reef Fish has also negatively affected the health of Coral Reefs.
Given the present rate of destruction, it is very apparent that we will lose more than 70 % of the Coral Reefs in the next ten years. This in turn will give rise to grave consequences, both ecologically and economically.
Conservation Efforts :
Coral Reefs can be only be saved if more and more people are made aware of both their importance and the dangers posed, and if the Coral resources are used in sustainable ways, without degradation and over-exploitation.
In recent times, to mention two positive examples, the people of Ambergris Caye in Belize and of Kenting in Taiwan have woken up to the need for conservation and are working on preserving the coral reefs in their areas.
Perhaps some good might yet come.
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