The Underwater Treasure: Coral Reefs

 Are they on the Brink of Disappearing?

Have you ever thought that the breathtaking underwater scenery in ‘Finding Nemo’ was just imagination? Think again. Under the ocean’s surface is a real-life wonderland: a vibrant, enchanted world where literally thousands of fish and sea creatures thrive in perfect harmony. This magical realm, blossoming with color and life, is none other than the mesmerizing ecosystem we refer to as coral reefs.

What Are Coral Reefs?

Coral reefs are phenomenal structures that are made by tiny creatures called coral polyps that are classified as cnidarians, which is the same phylum as jellyfish and sea anemones. Coral polyps have tentacles near their mouths, and the body is cylindrical in shape. Using these tentacles, they catch food. It also gives them protection, as these tentacles contain a cell called cnidocytes, which are stinging cells. These polyps live in colonies in which they secrete a calcium carbonate structure around them, making them a home, which we identify as a coral reef.

Types of Corals

There are 2 types of corals, hard corals and soft corals. Hard corals (e.g., brain corals) are made up of calcium carbonate, and they are generally regarded as the primary engineers of coral reefs, providing the solid surfaces on which new coral growth is established. Soft corals don’t have a rigid skeleton but instead have flexible, tree-like or plant-like structures supported by an inner wood-like core. Like hard corals, they live in colonies, adding variety and beauty to reef ecosystems.

In the historical side, we humans evolved 7 million years ago, dinosaurs 240 million years ago, and guess what, coral history goes way back to 450 million years ago. Not only for coral polyps, coral reefs are also the home to more than 25% of all known marine species. The high diversity in these ecosystems has given them the name “Rainforests of the sea”. The Great Barrier Reef in Australia, which is the world’s largest coral reef system, has 400 coral species, 1500 species of fish, 4000 species of mollusks, and 4 species of turtles. Coral reefs give food, protection, and habitat to the marine life, and in return, every animal has its own duty for the ecosystem it lives in, which is the ultimate way of keeping the balance in the ecosystem.

Coral Reefs in Sri Lanka

As proud Sri Lankans, we also have mesmerizingly beautiful coral reefs along the coastal area, attracting tourists, and many people make a living with the job opportunities and food sources created by the reefs. Hikkaduwa Coral Sanctuary, Pigeon Island National Park (Trincomalee), Bar Reef (Kalpitiya), and Great Basses and Little Basses’ Reefs (off Kirinda) are some of the areas with beautiful corals in Sri Lanka, which are popular tourist destinations for diving.

The Threat of Coral Bleaching

But day by day these colorful structures become white and pale. Its high diversity vanishes. No longer is the ecosystem there. It is all shattered, and the remaining’s symbolizes a graveyard that once was a flourishing land. But the question “Why?” kicks in. Where did it go wrong? And the sad truth is that all this is due to human impacts on the environment.

Coral bleaching is one of the major problems that can be seen due to the increase in water temperature driven by El Niño and global warming. The coral polyps have a symbiotic relationship with microscopic algae called zooxanthellae. Corals give these algae a place to live while the algae photosynthesize and produce carbohydrates and oxygen, which in return are given to the corals. It also gives the vibrant color to the corals. It is the primary food source of corals. These algae are very sensitive to temperature changes, and when the temperature increases, the algae are expelled from the coral. The algae are expelled, hoping that one day the required quality of water will be gained and the algae will be reabsorbed by the corals.

But due to the continuous pollution and heating by global warming, it will prevent the expelled algae from returning to the coral where they originated. Coral will starve and eventually end up dying. Scientists are now developing corals that can survive in warm waters, and there are naturally adapted corals for warm waters that they try to establish, hoping to keep the corals alive. Still some corals won’t survive at all and will vanish from the entire earth even without a notice.

Ocean Acidification and Other Threats

As the atmospheric CO₂ increases, CO₂ dissolves in water. It makes carbonic acid, and therefore the seawater is acidified. This declines the quality of water and reduces the availability of calcium ions, which is essential for the formation of the coral structures.  Corals may grow more slowly, and their skeletons can become brittle and more prone to erosion and breakage. It can also cause existing coral structures to dissolve under extremely acidic conditions. Overfishing, pollution, coral mining, and unsustainable coastal development are some of the reasons for the corals to die.

Corals are high-diversity areas with a large number of marine lives surrounded by it.Therefore fishing around corals Overfishing and unsustainable fishing practices are two of the major factors that cause corals to die. Dynamite fishing is used to explode underwater to capture a high number. of fish, and these cause corals to break into pieces.

Some fishermen spray sodium cyanide into the water to stun fish, especially for the live fish trade. But these cause the polyps to die and weaken large areas of corals. Bottom trawling is one method of fishing where large nets with weighted gear are dragged across the sea floor to catch fish and other creatures. These entangle with coral reefs, damaging and breaking them. Bottom trawling is one method of fishing where large nets with weighted gear are dragged across the sea floor for fishing. These entangle with coral reefs as well, damaging and breaking coral reefs.

The Intergovernmental Panel on Climate Change in 2018 warned that if the global warming continues and rises by 1.5 degrees, coral reefs could decline by 90%. If 2 degrees, it will be almost 99%.

Restoration Efforts

The Coral Restoration Foundation in Florida is growing corals in the sea and planting them by diving. Even though there are many foundations that work towards the protection of coral reefs, the damage done to the natural coral reefs is far more beyond the control of our hands as we try to recreate a legacy that has taken millions of years to form.

As another species living on this Earth, we humans are also benefited by Mother Nature’s creations. Coral reefs provide a global value of £5.7 trillion each year. This includes food, jobs, coastal protection, fishing, tourism, etc. Coral extract is also used for medications of asthma, arthritis, cancer, and heart diseases. While corals even help us to cure diseases, we are still harming our saviors, our food sources, and an entire ecosystem we rely on at risk. A treasure fading In front of our eyes, it is our duty to protect it. for the future generations. Let’s get together and protect the coral reefs for a vibrantly colored future.

By: Rtr. Thiyumi Wijemuni

Image Credits:

• https://tinyurl.com/bdecbrpa
• https://tinyurl.com/bdebrc97
• https://images.app.goo.gl/4ZwvXWnoe19mS2Yt6
• https://images.app.goo.gl/UtWhjASo24HjnBdx7

References:

• https://coral.org/en/coral-reefs-101/why-care-about-reefs/biodiversity/
• https://www.noaa.gov/education/resource-collections/marine-life/coral-reef-ecosystems