Most of us have never actually seen a coral reef and certainly not directly, close up. Why should we care about them, care about what happens to them? Even if you’ve only seen a coral reef on TV, one can appreciate their diversity and beauty. Added to that is the enormous range of sea life that live on, with and depend upon the coral reef. That may be reason enough to care about the coral reef, but the situation is more dire than many know: coral reefs around the world are dying as a result of smothering by sediment from poorly managed coastal land-use, toxins from industrial and agricultural pollution, overfishing and warming temperatures due to global climate change.
There are about six thousand species of coral around the world. Recent studies have revealed that 50% of the world's coral reefs have already been destroyed and another 40% could be lost over the next 30 years. Very few pristine reefs remain.
Though coral may look like a garden of colourful plants, it’s actually an animal. Corals are many individual creatures live and grow while connected to each other, they are also dependent on one another for survival. The tiny, individual organisms that make up large coral colonies are called coral polyps. The polyps use ions in seawater to make limestone exoskeletons.
Coral polyp bodies are usually clear. The amazing array of bright colours that characterise corals are actually caused by types of algae (specifically a type of algae called zooxanthellae) growing in the polyp’s tissue. The evidence of coral reef destruction is to be found in the extent of ‘coral bleaching’: this is actually caused by the algae leaving the coral due to warming sea temperatures (which the alga cannot tolerate) leading to loss of colour of the coral reef and the ultimate death of the reef.
According to London's Natural History Museum, coral reefs have an estimated global value of £6tn each year – partly a result of their contribution to the fishing and tourism industries (the young of many fish species spend their juvenile years protected by the coral reef). In addition, the reefs act as barriers and can reduce wave energy by up to 97%, providing coastal areas with crucial protection against wave action and threats such as tsunamis. Moreover, coral reefs help protect mangrove forests and seagrass beds that act as nurseries for marine animals, as well as both protecting and helping to feed or sustain human coastal populations (mainly through fishing) – directly benefitting more than 500 million people worldwide.