Coral Reefs – The Saviors and Multi-Taskers!
Almost every individual might have come across the word “Coral Reef”, while searching for a beautiful holiday destination away from the civilization or as a part of news headlines on television/newspapers for their miraculous properties that are saving the warming up globe. Some of you might have also seen the specimens of corals preserved in a laboratory.
If you are a ‘travel freak’, you might have also read about the famous “Great Barrier Reef” in Australia which is the world’s largest coral reef, a natural wonder and a world heritage site. It houses nearly 3000 individual reefs.
So far so good! But, what is a coral? Is it a plant or an animal? How are these reefs formed? How did they manage to secure a place in the list of “greatest creations of God?” What are they doing for the environment? Why are they considered “a habitat” for a large number of marine and endangered species? Why is it that the environmentalists throughout the world are making a hue and cry about the damage caused to these reefs?
Come; let’s get answers to these questions and many more amazing facts about this “Metropolis under the sea.”
Corals & Coral Polyps:
A coral is most of the time mistaken for a plant or a rock because of its hard yet branched out appearance. It belongs to animal kingdom and is related to jelly fishes and anemones.
Coral is a hard structure formed with calcium deposits. These deposits are secreted by several fragile and tiny animals known as coral polyps that inhabit the corals.
In general, the term “coral” is the combination of these tiny coral polyps and the skeleton left behind by them after their death.
Coral Polyps belong to the group of invertebrates (animals without a vertebral column or spinal cord). The body structure of a polyp is sac-like with a mouth or opening surrounded by tentacles. In order to protect its soft body, the animal builds a cup-shaped hard skeleton around it using limestone (calcium carbonate) from the sea water.
A coral colony is the word used to describe a single branch of the coral inhabited by several thousands of coral polyps.
What is a Coral Reef?
A coral reef is a massive structure of limestone formed from the deposits of corals. Out of several thousands of species that inhabit these structures, only a small fraction of them produce the limestone required for the formation of reef.
Coral Reef Construction:
Construction of these breath-taking structures requires the effort of millions of coral polyps inhabiting them. Not all coral polyps can build a reef. There is a separate category of coral building polyps known as hard corals or reef building corals.
Polyps living on the coral branches produce limestone skeletons around them during their growing years. These hard skeletons are left behind after their deaths which eventually become rocks. The next generation polyps use these skeletons as foundation and start building their own skeletons on top of the old ones. Because of this architectural strategy, you will find that the coral reefs grow upwards from the sea floor.
Where are they found?
Coral reefs can best grow in shallow, clear and warm waters with temperatures ranging from 21-29 degrees. Also they can survive only in salt waters.
You can find coral reefs in Indo-pacific and West-Atlantic oceans.
The Caribbean islands, the Bahamas, Bermuda, Florida, Gulf of Mexico and Belize come under Western Atlantic Ocean areas.
Indo-Pacific regions include: The islands of Philippines, Taiwan, coastal regions of Southeast Asia, Northern part of New Zealand and a major chunk of Australian coast.
Did You Know?
- Coral polyps live in a symbiotic relationship with zooxanthellae, the tiny algae that provide the required energy for polyps through photosynthesis (use sunlight to make sugar). In return, they get a safe shelter in the coral branches and food in the form of carbon dioxide released by polyps.
- The first Coral Reef was formed 240 million years ago. The age of the established reefs which are being visited by most of us now is between 5000 and 10,000 years.
- The vibrant and brilliant color of Coral Reefs comes from zooxanthellae. Yes, that’s right! The bodies of coral polyps are clear and their skeletons white just like human skeleton. The algae residing in the coral branches can produce pigments (color producing substances) in as small a space as 1 square inch. The ‘see-through’ nature of the coral polyp bodies makes these colors visible through the ocean water.
- Coral polyps grow very slowly, adding somewhere between 5 and 25 millimeters or 0.2 to 1 inch to their length every year.
- The varied shapes of corals depend on the species they belong to and on the location they are present in.
Coral Reefs – Some Fascinating Facts:
- Coral reefs are the largest living structures, some of which are visible even from space.
- Coral reefs are among the oldest ecosystems of earth.
- They are stretched out over less than 1% of the Earth’s surface, yet are considered as “Rainforests of the oceans” due to the presence of diverse animal communities including some of the very rare and endangered species.
- According to an estimate, 500 million people are relying on coral reefs for their survival.
- Porous limestone skeletons of corals are used as bone grafts in humans.
- Coral reefs protect their surrounding coastal dwellings, beaches and agricultural lands by acting as natural barriers to the destructive forces such as storms and tsunamis emanating from the sea.
- Because of their medicinal properties, coral reefs find a place in treating some terrible health conditions such as heart diseases, cancer, ulcers and HIV.
- Another estimate states that the monetary benefits generated by coral reefs every year, throughout the world, are nearly $375 billion.
- Coral reefs are home to 700 species of coral and more than 4000 fish species.
Why Save Coral Reefs?
So far we managed to get answers to more than half of the questions mentioned in the beginning of the article. Let’s now get to the real essence of the word “Coral Reef!”
- Tourism – Their spectacular beauty attracts tourists, scuba divers and snorkelers from all over the world generating evidential income for countries who depend majorly on tourism revenues.
- Only Shelter – A majority of plant and animal species inhabiting this complex ecosystem cannot survive in any other habitat. According to an estimate, more than 1 million species be it animal or plant are associated with coral reefs.
- Role of Buffer – They play the role of a ‘buffer’ in protecting the beaches and its surrounding human dwellings from storms and devastating waves. Coral reefs played a remarkable role during 2004 tsunami by preventing further damage.
- Miracle Medicine – Drugs for several life-threatening diseases have been prepared from the chemicals extracted from animals dwelling in coral reefs. Reef organisms are a major part of the ongoing research on cancer.
- Food – Coral reefs are a remarkable source of proteins for several million people.
Threats to Coral Reefs:
Both human-induced and natural activities are threatening the very existence of these extra-ordinary natural creations.
- Global Warming & Coral Bleaching – Due to global warming, several toxic and heat-trapping gases build up in air, preventing sun’s heat from escaping by acting as a blanket. These factors are raising the sea temperatures to abnormal levels leading to Coral Bleaching. This is a condition where the algae living on coral branches are expelled by coral polyps due to excess UV radiation or heat. This results in “bleached” (white) appearance of corals which could cause damage beyond repair.
- Ocean Acidification – Astronomical increase of the levels of carbon dioxide since the beginning of industrial revolution has had a destructive impact on environment and its dwellings. Oceans have been absorbing a large amount of the CO2 released into the atmosphere, which in turn is reducing the oceanic pH making it more acidic. This reduced pH also decreases the availability of carbonate ions, required by the marine organisms to build their protective shells. This phenomenon known as Ocean Acidification can have a negative impact on commercial shellfish and reef building corals.
- Water Pollution – This is considered to be another culprit that is gulping down the coral reefs. Reef animals can get killed by poisonous chemicals released into the water such as pesticides, fertilizers, gas, oil and animal and human wastes.
- Ozone Depletion
- Increased human dwellings in coastal regions
- Coral Mining – Corals are taken out from their natural habitats and used for human purposes. These include selling corals as souvenirs, making jewellery with them, crushing them into cement to be used for construction purposes etc.
- Reckless fishing practices
Coral reefs are in danger. According to an estimate, 11% of them have been lost and another 16% severely damaged. Another 32% will be lost in the coming 30 years if the above mentioned human-induced threats are not controlled.