If somebody asked you to describe corals, you’d probably say they form part of the colorful underwater garden marine animals swim through—similar to the school scene in Disney’s Finding Nemo or Finding Dory. While there’s no doubt that corals look fascinating, understanding their nature and how they are connected with people will help you appreciate them better.

What are corals?

We often assume corals are rocks or plants because of their shapes, sizes, and the way they seem to grow from the ocean floor. Surprisingly, they are not. Unlike plants, corals need to take in oxygen to survive, have a simple nervous system, and can’t make their own food.

To make things more fascinating, most corals are colonial organisms. This means they consist of thousands of living animals called polyps. Each polyp is similar to a very tiny bottle—it has an opening at one end and a space to store liquid. The opening is the polyp’s mouth, and the space is the stomach. Every time the polyp consumes food it goes through the mouth down to the stomach. It also uses the same opening to expel wastes.

The mouth is surrounded by tentacles that contain stinging cells called nematocysts. Corals use the tentacles for defense as well as preying on zooplankton and small fish. Nematocysts are also found on jellyfish tentacles. This gives us an idea that both corals and jellyfish belong to the same phylum, Cnidaria.


How coral reefs grow?

Corals exist in different parts of the ocean but the ones in warm, shallow waters are capable of building reefs.

These reef-building corals source food from algae called zooxanthellae. Both have developed a mutually beneficial relationship in the ocean. Along with water and sunlight, algae use carbon dioxide released by the corals to produce their own food. This is a process known as photosynthesis. In return, the corals use photosynthesis byproducts—oxygen, sugar, fats, etc.—for respiration and building huge structures called reefs.

It takes hundreds to thousands of years for a reef to fully form. Corals grow at different rates depending on several factors such as water temperature, salinity, and availability of food. Staghorn and branching corals grow as much as 10 centimeters in a year, but massive corals only get up to 2 centimeters of growth within the same period. The Great Barrier Reef, the world’s largest coral reef, started to exist about 500,000 years ago.

Because zooxanthellae need sunlight for photosynthesis, most reefs are located in countries close to the equator. They also exist in places where warm currents flow out of the tropics, such as Florida. The Pacific and Indian oceans house most of the coral reefs in the world.

How important are coral reefs

Although reefs occupy less than 1% of the ocean floor, they are home to 25% of marine animals. That’s how diverse these “underwater rainforests” are! But their value doesn’t end in supporting biodiversity. Reefs also benefit people by providing:

  1. Healthy seafood. Fish is loaded with protein, omega-3 fatty acids, and other vitamins and minerals. It also reduces the risk of heart disease.
  2. 70% of the oxygen we breathe. Rainforests produce only 28% of the Earth’s oxygen. 2% comes from other sources.
  3. Revenue from fisheries and reef-based tourism activities such as scuba diving and snorkeling.
  4. Protection against erosion, property damage and loss of life during catastrophes. Reefs break the power of waves during typhoons, hurricanes, and even tsunamis.
  5. Contributions to future medical advances. Some reef organisms are being used for treating diseases like cancer.

How to protect coral reefs

Given how valuable coral reefs are, protecting them should be a priority for everyone. Fortunately, you don’t need to be a marine biologist or researcher to make a difference. You don’t have to live in a coastal area to be active in promoting reef health. You can create positive effects on coral reefs through simple everyday habits, such as:

  1. Educate yourself about coral reefs. Get to know the different species that live in reefs, how they relate to other organisms, their conservation status, etc. Self-awareness lets you appreciate the value of coral reefs.
  2. Share your knowledge about marine life with your friends. Write a blog, share articles on social media, or create a simple video.  Spreading the word inspires others to be involved.
  3. Dispose of garbage properly. Don’t litter on the beach. Develop the habit of picking up your own (and others’) trash.
  4. Support businesses that advocate marine conservation. For instance, companies like Biota Aquariums that are members of 1% for the planet make a commitment to donate a part of their revenue to nonprofits that advance environmental sustainability.
  5. Join a reef, coastal, or city cleanup. Picking up trash reduces the likelihood of plastic drifting into the ocean and being consumed by sea animals.
  6. If you dive or snorkel, don’t touch marine life. Remember – take only pictures and leave only bubbles. Avoid any form of contact with corals to protect yourself from harm and to prevent any damage.
  7. Read existing and proposed laws, projects and programs that affect coral reefs. Learn what the government does to save the ocean.
  8. Donate to ocean conservation organizations such as the Coral Restoration Foundation in Florida. Reef programs need financial support to sustain their initiatives.