The importance of Coral Reefs (and the threats they face)

What are coral reefs?

A surprising fact for many people is that coral reefs are actually animals. Coral reefs are made up of small invertebrates called ‘polyps’ ( which they are related to jellyfish) and together they form large colonies and act as an organism. It has taken thousands and millions of years for these colonies to grow and reach their current size. They use calcium carbonate to build their exoskeleton and grow bigger and bigger.

Why are they important?

No one can deny that coral reefs are important. They do a lot, not only for us but for the whole planet. But what exactly do they do?

Protects coastlines

Coral reefs protect us from flooding, tsunamis, and more by reducing the flow of water and consequently, minimizing the impact and damage done to coastlines and the communities that live there. Furthermore, they protect mangroves and reduce erosion.


These ecosystems are very biodiverse. Coral reefs cover a very small percentage of the earth’s ocean floor but they are home to around 25% of all marine life. Millions of different species live there and have adapted to live there. This means if they were destroyed we would lose all that biodiversity since most of the marine life wouldn’t be able to survive anywhere else.

Provide Food

Especially in developing countries, people rely on fish for protein. Corals that are managed sustainably can be a source for a large amount of fish. Some even sell what they catch to earn money. Hence, coral destruction is causing major difficulties in some countries as they can’t find enough food to eat.

Filter the water

They filter particles out of the water and increase water quality. That’s why the water is always so clear around coral reefs.


It attracts people to the area bringing the economic wealth. They also provide activities for tourists such as snorkeling. Some countries depend heavily on tourism so, without them, some economies could collapse.


Human activity such as pollution and global warming is threatening these biodiverse ecosystems. Coral reefs date back to over 400 million years ago but we have already destroyed over 50% of them in only a few decades.

Ocean Acidification

CaCO3 + CO2 + H2O -> 2HCO3 + Ca2+

Warming Waters

Coral bleaching happens as a result of warming waters. In these temperatures, they get stressed and release the algae that have been living on them. They get stressed due to the fact that the algae are doing more harm to the corals at these temperatures and no longer have that symbiotic relationship.


Mining, farming, and other human activity is adding more sediment particles to the ocean floor. These block sunlight and therefore, algae and other plants can’t photosynthesize. No ecosystem can self-sustain itself without sunlight.


Overfishing is a global problem that is affecting countries and communities around the world. Not all fishermen carry out sustainable practices. Catching too many fish in a short period of time disrupts the food web in many ways.


This includes rubbish, sewage, oil, plastics, and agricultural chemicals. Each type of pollution has different effects on this ecosystem. Some chemicals poison the corals, others block sunlight and some can even change the acidity of the water. Most things, if not everything, that we are dumping in the ocean is toxic to corals and to every other organism.


Even though coral reefs are good for tourism and the economy, there are problems with it. It’s true that it gives people the chance to appreciate how beautiful the earth is but careless tourism is becoming more of a threat to them.


We can’t afford to lose our coral reefs, which is what is predicted to happen if we continue at this rate. It took millions of years for them to become the extraordinary ecosystem they are now and it would take a lot of effort and time to help them restore them.



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