You may have already heard about the damage that has been done to coral reefs in our oceans through documentaries like Chasing Corals and Life On Our Planet. The immense degradation of these beautiful parts of the Earth’s oceans is not breaking news in any way. It is a result of the sky-rocketing anthropogenic climate change that has taken place over the last few decades. Coral reefs do much more than add beauty to the oceans and vibrance to the planet. They are integral to the marine system, with thousands of species depending on these reefs. Corals are also instrumental in lessening the effects of hurricanes, and they provide sources of medicinal products that are necessary for human beings. They are one of the biggest players in maintaining the balance of our planet, but their once magnificent rainbow of colors has been bleached to an eerie white.

 

Corals are sessile animals that we usually find in coastal waters. Sessile means that they take root on the ocean floor permanently. There are many species of this animal. Corals in general are made up of tiny creatures called polyps. These are extremely small creatures that secrete a hard outer skeleton made of limestone that attaches to rock or the dead skeletons of other polyps. Over time these structures grow to tremendous sizes. The reason coral bleaching is such a horrifying event is because it is an indicator of a stress response. When corals experience stress due to changes in temperature, light, or nutrients, they expel the symbiotic algae that are their food source and turn snow-white. Bleaching does not indicate death, but it does mean that the corals are weaker, under duress, and subject to mortality. Many that turn white, eventually starve and die, turning a dark brown color. It is vital that we help corals recover from bleaching events and instead thrive.

Coral bleaching events were first noticed in the 1980s, which is not too long ago. The problem worsened as the oceans warmed in the last few decades. A question many people have is why coral reefs are important for the planet. Well, for starters, each major reef contains almost 5000 marine species. The Great Barrier Reef in Australia has six of the seven sea turtle species in the world. The Coral Triangle which is a coral-rich region in Southeast Asia is the most biologically diverse marine ecosystem on Earth. When these reefs die, many species that depend on the reef as a food source or for protection from predators are left to struggle to survive.

 

Additionally, more than 500 million people in the world depend on reefs for food, livelihood, and coastal defense. As mentioned before, reefs can help reduce the intensity of hurricanes and generally protect from marine-related calamities like tsunamis. This is largely because reefs behave as barriers that rise close to the surface, which can reduce wave energy by up to 97%; a staggering number. They protect the people that live in these coastal areas from otherwise devastating consequences. Reefs also facilitate land growth at the surface of bodies of water and prevent coastal erosion. They are so effective at buffering damage to coastal areas that some countries and fragile coasts would not exist without corals.

Corals behave like trees in a way, providing a structural home to small fish and other marine animals that many coastal populations depend on for food. It has actually been estimated that 1 billion people may depend on food from coral reefs.

Corals also supply medicines that are effective against conditions like asthma, arthritis, cancer, and heart disease. Some medicines depend on bacteria and fungi that exist naturally in these reefs.

So, how are these reefs dying? It is a combination of warmer oceans, pollution, ocean acidification, and overfishing. It is also possible to directly cause physical damage to the corals. Land-based pollutants can enter the ocean through dredging, agricultural activities, and sewage plants. There are a lot of harmful pollutants that enter the ocean this way. However, nutrients can also be a part of these land-based discharges. Nutrients may inherently sound like a positive thing, but they cause extremely rapid algae growth with can smother corals. Oil spills can also disrupt the growth of corals if the spill occurs when the corals are spawning and growing.

Careless divers that roam the coastal regions, collecting for jewelry or aquarium trades, can trample fragile corals. A lot of fishing techniques are also detrimental to the corals. Net fishing is already destructive because of the debris it leaves behind, which can get entangled and break apart corals, but many fisheries also use dynamite or other explosives to scare fish out of hiding places. This can directly kill corals and other marine species, but it can also generally cause high amounts of stress. This stress can make the corals expel their zooxanthellae. Zooxanthellae are plant cells that live within most corals that provide food to the corals through photosynthesis; they are essential for survival.

And of course, global warming is a major contributing factor to the degradation of corals. Human activities that contribute to increasing the carbon dioxide levels in the air can lead to rising ocean temperatures, which in turn changes storm patterns. Storms can form and strengthen over warm water. Temperature changes, even by a degree cause monumental degrees of change in the Earth system, contributing to coral bleaching.

Now comes the question, how are we solving the problem? Thankfully, many organizations are taking action to protect corals. Some conservationists are exploring natural selection to keep corals afloat. They are harvesting samples of corals that have survived environmental stresses, naturally, through thermal tolerance, breeding them by hand, and reattaching them to the reef. This might help the corals evolve to sustain themselves while we take measures to reduce the impacts of climate change.

Conservationists in Massachusetts have found two key elements that seem to protect corals: internal waves that bring cooler currents from deeper ocean to the warm water near the corals, and adaptation. It is astonishing how quickly some corals have adapted to keep themselves alive with temperature change. Areas that have these corals are termed ‘super reefs’. They can be the key to helping corals sustain themselves in the warmer waters (which shouldn’t be so warm in the first place). Even the conservationists know that these measures are only preventing a functional extinction for the time being; there needs to be a radical change to restore their environments to become hospitable instead of tolerable. Hence, most scientists point towards mitigating climate change as the biggest and only long-term solution to conserve the coral reefs.

It is sad to see such an important and beautiful part of the planet face such terrible consequences. That includes the coral itself, and the thousands of species that call corals home. While saving the planet from such destruction shouldn’t need to directly benefit us, it does anyway. Saving these reefs will protect coastal regions from extensive damage, and provide economic growth through the abundance of resources that corals house within them. There is only one main solution we can work toward that will save not only corals but the entire planet from irreversible destruction; mitigating climate change.

 

Sources

1. US Department of Commerce, National Oceanic and Atmospheric Administration. “Anthropogenic Threats to Corals – Corals: NOAA’s National Ocean Service Education.” Human Threats to Corals: Corals Tutorial, 1 June 2013, oceanservice.noaa.gov/education/tutorial_corals/coral09_humanthreats.html.
2. “Why Are Coral Reefs Important?” Natural History Museum, www.nhm.ac.uk/discover/quick-questions/why-are-coral-reefs-important.html#:~:text=Coral%20reefs%20provide%20an%20important,found%20living%20on%20one%20reef.
3. Gibbens, Sarah. “The World’s Coral Reefs Are Dying-Here’s How Scientists Plan to Save Them.” Science, National Geographic, 10 Feb. 2021, www.nationalgeographic.com/science/article/scientists-work-to-save-coral-reefs-climate-change-marine-parks.
4. US Department of Commerce, National Oceanic and Atmospheric Administration. “The Importance of Coral Reefs – Corals: NOAA’s National Ocean Service Education.” Corals Tutorial, 1 June 2013, oceanservice.noaa.gov/education/tutorial_corals/coral07_importance.html.
5. “The Importance of Protecting Coral Reefs.” Coral Guardian, 25 Nov. 2020, www.coralguardian.org/en/coral-reef-important/.
6. “Coral Reef Ecosystems.” Coral Reef Ecosystems | National Oceanic and Atmospheric Administration, www.noaa.gov/education/resource-collections/marine-life/coral-reef-ecosystems.
7. “The Importance of Coral Reefs.” Reef Relief, 31 Jan. 2011, www.reefrelief.org/the-importance-of-coral-reefs/.