Coral reefs, also known as “rainforest of the sea,” cover less than 1% of the ocean but are home almost 25% of all known marine species. That's over 4,000 different species of fish that rely on coral reefs. They are the largest biological structure on earth, and are generally found in clear shallow water. Most coral reefs are found in between the Tropics of Capricorn and Cancer.

What is coral?

Coral is made up of millions of coral polyps which are small colonial animals that look a bit like small overturned fish and they use carbon dioxide from the water and turn it into limestone. Corals are actually animals that fall under the phylum Cnidaria and class Anthozoa, and are relatives of jellyfish and anemones. Corals can exist as individual polyps or in colonies. Coral occasionally eats, it’s prey can be as big as a small fish, like a shrimp.

Types of Coral 

Hard coral, also known as Seleranetinian or stony coral, are marine animals and are very similar to sea anemones but have a hard skeleton. Hard corals are Colonial coral, which are found in clear, shallow water, they are the world’s primary reef builders. Another type of coral is Alcyonacea or more commonly known as soft corals are an order of coral that does not produce calcium carbonate for skeletons, so they are not reef building corals. They do however have minute, spiny skeletal elements, called selerite. The flesh of Soft coral has a spiky, grainy texture that detects predators and they thrive in nutrient rich waters with less intensity. If you touch any type of coral, especially hard three times, it will turn grey and die. 

The perfect place for coral reefs to grow is no deeper than 50 meters and not warmer or cooler than 20-28 degrees Celsius. However, coral reefs can be found at depths lower than 91m. Normally reef building corals can be found at depths shallower than 70m.

Coral reefs are extremely sensitive to changes in light, temperature, overfishing, damaging fishing practices, and pollution. Increasing changes in temperature lead to coral bleaching, which is when coral is basically cooked to the point where all the colour and life is sucked out of it. Pollution is clouding the waters making it harder for light to get through, meaning that the algae, it’s scientific name is zooxanthellae, which manufactures photosynthesis for coral, can’t get any sun rays to manufacture photosynthesis for the coral. Damaging fishing practices and overfishing are a big part of destroying coral reefs. One of the fishing practices is fish bombing, which is when a fisherman makes a bomb and puts it in a jar, bottle, or basically anything, and throws it into the sea for it to blow up seconds later killing all the fish and coral in smallish patches.

Many coral reefs that were once beautiful splashes of colour filled with life, are now waste lands. By 2030 more than 90% of the world's coral reefs will be threatened by human activity. We should stop this from happening as coral reefs protect coastlines from erosion and storms. But we can save them by spreading awareness of this issue, and doing small things like recycling, and not driving when possible and instead walking or cycling. We should stop this from happening as coral reefs protect coastlines from erosion and storms. Please help save our world's coral reefs.