If all coral reefs die, the Earth will experience multiple stresses and the extinction of various species.
Have you ever considered the multitude of creatures that rely on planet Earth? Aside from the 7.8 billion Homo sapiens, there are countless animals, from tiny insects to free-flying birds, creepy reptiles, water-dwelling fish, and a wide range of mammals, including large carnivores and small pets. And let’s not forget the countless types of plants, from fragrant flowers to insect-devouring species. And there are also billions of organisms that are invisible to the naked eye, such as bacteria, fungi, viruses, and everything in between.
Out of all these organisms, only 1.2 million species have been discovered, and most of them exist on land. If you were to embark on the monumental task of discovering every organism on this blue planet, it would take you more than a thousand years! And during that time, countless new organisms would evolve.
However, the beauty of this diversity lies in the fact that each organism is important and provides support for other organisms in various ways. One of the wonders of this diversity is coral reefs.
What Exactly is a Coral Reef?
If you’ve heard about Australia’s “Great Barrier Reef,” you may have some understanding of what a coral reef is. However, if you think it’s a type of sea rock or plant, you’re mistaken.
Australia’s Great Barrier Reef (Photo Credit: superjoseph/Shutterstock)
So what is this vast “creature”?
A coral is a marine invertebrate that is related to the sea anemone. It has a cylindrical body with tentacles, which is why it’s called a “coral polyp.”
There are two types of corals: hard and soft.
Hard corals absorb calcium from the ocean and produce their own calcium carbonate shells. Soft corals, on the other hand, do not possess such structures. It is the formation of these shells that allows hard coral polyps to create massive coral reefs.
Coral polyps live in colonies, so there are always many polyps in close proximity. When the polyps die, they leave behind their limestone shells. Layers of shells continue to accumulate, transforming the original small colony into a coral reef.
The Coral Reef Environment
The Symbiotic Relationship
Coral polyps do not live alone. They have a symbiotic relationship with microscopic algae called zooxanthellae. Zooxanthellae generate food for the coral polyps through photosynthesis, while the polyps provide protection for the algae in their calcareous shells.
Coral Polyps (Photo Credit: Ethan Daniels/Shutterstock)
In fact, corals live near the ocean surface to ensure that zooxanthellae receive enough sunlight for photosynthesis. Additionally, since zooxanthellae come in various colors, they impart the same color to the coral!
Impact on Geology
Under favorable conditions, coral polyps can reproduce in large numbers. Sometimes, these structures expand to the point where they form islands!
Coral reefs form around underwater volcanoes, gradually sinking as the volcano erodes. Despite being fully submerged, the reef continues to grow as sand particles and solidified magma create a new island. Coral islands, such as those in Maldives, American Howland Islands, and India’s Lakshadweep group, are formed in this way. However, the true importance of coral reefs lies in their ability to support life globally.
Coral reefs are vital habitats for many organisms, earning them the title of “rainforests of the sea.” A quarter of all marine creatures rely on coral reefs for survival, whether as a food source or for shelter in their calcareous shells. Remarkably, these reefs cover less than 1% of the ocean floor and a small fraction of Earth’s surface.
For example, the coral reefs in the Northwest Hawaiian Islands support a diverse range of mammals, birds, plants, and over 7,000 species of fish and other sea creatures. Additionally, 25% of all fish species depend on coral reefs despite their limited distribution. Even the Yellow Tang, a popular pet, breeds around coral reefs and plays a crucial role in maintaining the ecosystem’s cleanliness. In return, the corals provide protection from larger carnivorous fish.
Coral reefs also provide numerous benefits to humans. Commercially important fish like snapper and grouper rely on coral reefs for survival, and lobsters are commonly found in these reef systems. Coral reefs are essential landmarks for fishermen and the food processing industry, with over a billion people depending on coral fish as a food source. The commercial and recreational reef fisheries in the US alone are valued at $100 million. Furthermore, coral reefs contribute significantly to the tourism industry. In Hawaii, 60% of tourism income is generated by reef tourists.
In addition to their ecological and economic value, coral reefs have also been instrumental in the development of medicines used to treat cancer, heart disease, and Alzheimer’s. Extracts from the Caribbean reef system, for example, were used to create an anti-cancer agent called Ara-C.
Furthermore, coral reefs play a crucial role in the production of oxygen. Approximately 80% of the oxygen consumed by humans comes from the oceans, and coral reefs contribute significantly to this atmospheric output.
In conclusion, coral reefs are of immense importance for the survival and well-being of countless organisms on our planet.
Are Coral Reefs in Danger?
Coral reefs are currently facing significant pressure and threats. The decline of coral reefs can be caused by natural factors or human activities. Natural causes include diseases and tidal fluctuations, which expose the corals to direct sunlight. However, the accelerated decline of coral reefs is primarily due to human-made causes.
The majority of coral reefs are found in tropical and sub-tropical regions because they can only survive within a narrow temperature range of 22-29°C. Unfortunately, with the increase in global temperatures due to global warming, the reefs are under immense pressure.
Elevated temperatures cause coral polyps to expel zooxanthellae and terminate their symbiotic relationship. This phenomenon is known as coral bleaching. Bleached corals become white in color and gradually die as they lose their source of food.
Coral Bleaching (Photo Credit: Sabangvideo/Shutterstock)
The primary cause of rising sea temperatures is the burning of fossil fuels. However, fossil fuels also contribute to a significant increase in carbon dioxide levels. As early as 2007, the carbon dioxide level in the atmosphere exceeded the maximum limit at 380 ppm. Currently, it has risen to 410 ppm!
Oceans act as carbon dioxide sinks, absorbing excessive concentrations from the atmosphere. Carbon dioxide combines with ocean water to form carbonic acid, a process known as ocean acidification. The higher the acid concentration in the ocean, the lower the number of carbonate ions. As a result, corals lose their ability to form calcium carbonate shells, leading to the rapid loss of coral reefs.
In addition to these processes, other human activities such as overfishing, oil spills, and improper waste disposal techniques also contribute to the degradation of coral reefs.
What Would Happen If Coral Reefs Disappeared?
Coral reefs do not develop quickly. They are slow-growing organisms, with a growth rate of approximately 15 cm per year. The magnificent Great Barrier Reef, as we know it today, has been forming for 20,000 years!
The disappearance of coral reefs from our planet would have a cascading effect of mass destruction. Many marine species would vanish when their only source of food disappears permanently. Parrotfish, colorful fish with large beaks, spend their days chewing coral and living around them. They would have to search for new sources of food, along with thousands of other species.
Other species, like pygmy seahorses, would face a greater threat from larger predators, as there would be limited places to hide.
The danger also extends to humans. Coastal regions may experience a severe food crisis as numerous fish populations decline. The healthcare industry would also face significant stress, as a major source of life-saving drugs would be lost.
Climate change and bleached coral would make coral-based tourism unattractive or non-existent, resulting in job losses. Developing countries and small island nations like Tuvalu would be the most affected by these drastic changes.
Coral Reefs around the World are under Stress (Photo Credit: fenkieandreas/Shutterstock)
Coral reefs provide protection against flooding and coastline erosion. Without them, coastlines would erode rapidly, and many small island nations could disappear from the world map. There may be other serious consequences that we cannot currently foresee.
It is not a hypothetical situation or a product of our imagination, but rather a real threat. The Intergovernmental Panel on Climate Change warns that a mere 1.5°C increase in global temperature could result in the extinction of 70-90% of coral reefs worldwide. This percentage could rise to 99% if the global temperature increases by 2°C.
Given that a significant portion of coral reefs has already been lost, the focus now is on preserving what remains.
Various initiatives, such as the International Coral Reef Initiative, have been implemented by international organizations and governments worldwide to safeguard coral reefs. However, these efforts will be futile unless every individual is willing to collaborate and confront this crisis directly.
This issue is not solely about coral reefs. Regardless of how insignificant a species may seem, the extinction of even one can have severe consequences for the global food chain. Therefore, it is our collective responsibility to ensure a better future not only for ourselves but also for every creature that inhabits this planet.