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PROTECT: Coral reefs


Coral reefs are the most diverse and beautiful of all marine habitats.

Large wave resistant structures have accumulated from the slow growth of corals. The development of these structures is aided by algae that are symbiotic with reef-building corals, known as zooxanthellae. Coralline algae, sponges, and other organisms, combined with a number of cementation processes also contribute to reef growth.

The dominant organisms are known as framework builders, because they provide the matrix for the growing reef. Corals and coralline algae precipitate calcium carbonate, whereas the framework- building sponges may also precipitate silica. Most of these organisms are colonial, and the slow process of precipitation moves the living surface layer of the reef upward and seaward.

The reef is topographically complex. Much like a rain forest, it has many strata and areas of strong shade, cast by the overtowering coral colonies. Because of the complexity, thousands of species of fish and invertebrates live in association with reefs, which are by far our richest marine habitats. In Caribbean reefs, for example, several hundred species of colonial invertebrates can be found living on the undersides of platy corals. It is not unusual for a reef to have several hundred species of snails, sixty species of corals, and several hundred species of fish. Of all ocean habitats, reefs seem to have the greatest development of complex symbiotic associations.

1 What is Coral Bleaching?

Coral is a living organism that was initially believed to be a plant, until in the 18th century under microscope it was found that coral is created by a Polyp that has cell membranes like an animal. These polyps start life as larvae, smaller than a grain of sand they live in the open water for up to 30 days until it finds a place to settle. This larvae then grows into a polyp which looks like a tiny upside down jellyfish that uses its small tentacles to trap and eat small fish and plankton for food plus absorbing algae called “zooxanthele” the main source of nutrients as they turn sunlight into food for the polyps. These polyps band together in the 1,000s and all secrete a hard calcium waste that can be bright in colour, like a polyp house, and over many years builds up creating a hard calcium reefs with bulges and towers.

Coral is very sensitive to change.  If the temperature of water increases by just a couple degrees, the coral become stressed and zooxanthele will move out.  The coral loses its main source of food its color.  This is called coral bleaching.

Mass coral bleaching can happen when the sea stays too warm for too long and huge areas of coral can be affected.  It the sea temperature returns to normal quickly enough the coral can recover otherwise bleached coral will die.  Coral bleaching due to climate change is a major problem and Phuket was a victim to warmer waters in 2010 that has bleached as much as 25% of the local reefs in one year.

2 What causes Coral Bleaching?

Greenhouse gases comprise Carbon Dioxide (CO2), Methane (CH4), Chlorofluorocarbon (CFC), and Nitrous oxide (N2O).

Coal-based power plants are major Carbon Dioxide emitters, as are Industrial factories. The tree is the most important absorber of Carbon Dioxide but as humans destroy them for such small benefits deforestation is becoming a great risk to the world’s natural ability to deal with excess carbon dioxide. Air-conditioning and airplanes are also major source of CFC emissions whilst surprisingly global livestock have a major impact with Methane gas emissions.

All of these gases float to the atmosphere and form the Greenhouse Effect which prevents sunlight from reflecting back to the atmosphere causes Global Warming including heating the world’s oceans. If increased temperatures and coral bleaching continues the coral will die and there will be no reefs, which without impacts all marine animals and dramatically reduces the number of fish in the ocean.

03 How can we help?

Boy:     Oh no! All coral are bleaching!

Girl:      That’s bad. We need to find ways to help.


First of all, turn off the unused electrical devices.

Change to energy-saving light bulbs.  Compact Fluorescent Light bulb (CFL)) uses only 1/5 electricity comparing to the normal light bulbs.

Reduce plastic bags usage and change to use cloth bags.

Be aware that the plane is one of the causes of Global Warming and reduce your travel.

Use public transportation instead of your personal car is another way to help and it is also cost effective.

Walking or riding a bike also helps to save energy and are good exercise.

Tell your family and friends this story, help them to save money and save the world.

People: What are they doing over there?

Let’s go and see!

Wow! What is this?

Does everyone know what causes the coral bleaching?

Burning fuel is the major cause of global warming such: cars, buses, planes, factories & power plants are all major sources.

We need to reduce energy usage, stop completely fishing in coral reef with more protected areas, stop boats anchoring in the reef, stop people stepping on the coral reefs at low tide, and ask tour guides to provide tourists the information purposely to build awareness among them.

Importantly tourists should stop fish feeding because:

  1. It changes the fish’s behavior; they will stop finding food and only wait for feeding from human being. For example, the Surgeon fish and parrot fish usually nibbles the seaweed over the rock and dead coral which opens and prepares the best place for baby coral to land and grow. When fed by human being, they stop eating the seaweed harming the eco-system.

  2. The leftover from fish feeding also increases nutrient in seawater causes the accelerated growth of seaweed. As seaweed grows much faster than the coral it then spreads over and invades the space where coral is growing. When the bleached coral is dead, the seaweed will take the space. If we stop fish feeding, the eco-system and coral will eventually naturally be restored.

If we help to reduce global warming by reducing energy usage and by protecting the reefs then bleached coral will be revived and be as beautiful and colorful as it should be leaving a healthy reef, lots of fish and a normal ecosystem.

JUNE 2012


Corals living on reefs near populated coastal areas have it rough—particularly near rivers that flush large plumes of sediment from land into the coastal waters.

As if being buried alive weren’t bad enough, microbial activity within the sediment that settles onto coral colonies may give them less than a day to live.

ANALYSIS: Coral Suffering Before Climate Change

A team of marine microbiologists now thinks they know why terrestrial run-off can be such a quick coral killer. Led by Miriam Weber of the HYDRA Institute in Italy and the Max Planck Institute for Marine Microbiology in Bremen, Germany, the team conducted laboratory experiments and intensive monitoring of sediment-laden corals in Australia’s Great Barrier Reef.

Their experiments revealed a deadly chain reaction that they spell out in a recent report in the Proceedings of the National Academy of Sciences:

Phase 1: A thin layer of sediment smothers the corals.

Blocked off from the light, symbiotic algae living in the corals will stop producing the oxygen the corals need—even if the sediment layer is only two millimeters thick.

Phase 2: Lack of oxygen and acidification damage small areas of coral tissue irreversibly.

If the sediments contain even a smidge of organic matter, microorganisms start decomposing it right away, quickly reducing oxygen concentrations beneath the sediment film to zero.

Acidification is an immediate problem as well: Other microbes digest larger carbon compounds via fermentation and hydrolysis, both of which lower the ambient pH.

“We were amazed that a mere 1% organic matter in the sediments is enough to trigger this process,” Weber said in a press release.

Phase 3: Hydrogen sulfide kills the remaining cells.

A third type of microbe begins digesting the dead patches of coral tissue, producing hydrogen sulfide, a compound that is highly toxic for the remaining corals. The process gains momentum and kills the remainder of the sediment-covered coral surface in less than 24 hours.

ANALYSIS: What’s the Coral Sea Without Coral?

Such were probably the three phases of death for this section of reef off the coast of North Queensland, Australia:

That’s the harsh reality, folks. All the more reason to promote strong management practices and regulations that minimize the nutrient pollution—topsoil, fertilizer, animal waste and sewage—that washes into tropical coastal seas.


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