Coral Reef: Definition and Meaning

Coral reefs are one of the most fascinating structure under the water that provide rich and diverse ecosystems under the oceanic water. Such underwater features grouped with various marine life and form an essential habitat for numerous species.

What does Coral Reef Exactly Define?

Primarily formed by the accumulation of coral polyps (specifically calcium carbonate skeletons), coral reefs are huge underwater structure. The coral polyps, which aer the tiny, soft-bodied sea organisms belong to the class Anthozoa, phylum Cnidaria and class Anthozoa. Over period in time, these corals grow and expand swiftly; likewise, they create big and intricate colonies, which eventually forms foundation of coral reefs.

Furthermore, because of its richness and diversity, sometimes, it is called as the “rainforests of the sea.” Secondly, such rich and diverse region plays influential role in maintaining the marine biodiversity, supporting fisheries, and protecting the coastal regions.

Geographical Distribution

Coral reefs do not found everywhere, but rather it requires very specific geographical requirements such as warm, shallow, and nutrient-rich waters. So, the ideal regions where coral reefs feel comfortable to grow are tropical and subtropical regions.

Formation of Coral Reef

The formation of coral reef begins with the deposition of coral polyp on a submerged substrate. With its fast growth, it forms colony and over period in time, this colony keeps growing and forms complex structures with diverse species inhabiting them.

The Role of Zooxanthellae

Zooxanthellae is a tiny photosynthetic alga that makes symbiotic relationship with coral reefs. These algae live within the coral polyps’ tissues and consistently provide some essential nutrients to them through photosynthesis. On the other hand, the coral polyps provide shelter and carbon dioxide to the algae. This symbiotic relationship creates a favorable environment for the swift growth of coral and facilitates reefs to flourish in nutrient poor waters. This is how coral reef forms.

Types of Coral Reefs

Following are the major types of coral reefs −

• Fringing Reef − Also known as shore reef, a fringing reef is formed nearby shore or borders around a prevailing narrow, shallow channel or lagoon. Likewise, fringing reefs follow coastlines, but it can be extending for many kilometres. It is the most common reefs and its width, usually less than 100 meters, but at a few places, it extends more than 100 meters wide.

• Barrier Reefs − Barrier reefs are somehow distinct from the fringing reef, as it is separated from a mainland or island shore by a deep channel or lagoon. Its lagoon can be several km wide and depth usually varies between 30 and 70 meters deep. The most popular and largest example of a barrier reef is the Australian Great Barrier Reef.

• Atolls − Atolls are the types of reefs; which shapes are usually circular. Sometimes, the continuous barrier reef all around a lagoon (without a central island) forms like atoll. Likewise, it normally formed from fringing reefs specifically around the volcanic islands. Over period in time, the island either erodes away or sinks below the sea level and atoll appears. For example, such atolls are commonly found in the South Pacific Ocean, such as around Caroline Islands, Cook Islands, French Polynesia, etc.

Biodiversity and Marine Life

Coral reefs are known for providing habitat for an amazing array of marine species. Because this reason, these regions of coral reefs are popular as the most biodiverse ecosystems on the oceanic water. It provides habitat for various species including fish, invertebrates, and many other marine organisms. Interestingly, the colorful reef fish such as clownfish and parrotfish are found in abundance. Besides, invertebrates, such as sea stars and sea anemones are also found in large quantity.

Challenges to Coral Reefs

In the present era, because of increasing human movements and activities and climate change collectively put threats on coral reefs. However, some of the major threats are −

• Coral Bleaching − It needs very ideal weather condition, but the increasing temperature put stress, forcing them to expel the zooxanthellae. This act further causing loss of color, which is known as coral bleaching. If such bleaching exists for long times, it may cause to coral death and eventually reef degradation.

• Ocean Acidification − As we know that oceans absorb the excessive carbon dioxide of the atmosphere, but these days, the quantity of atmospheric carbon dioxide has increased, as result of this oceans are also absorbing more carbon dioxide, which directly increasing the acid quantity of ocean. The acidic water has put greater threat on corals to build their calcium carbonate skeletons, which ultimately restrain free growth.

• Faulty or Excessive Fishing Practices − Unregulated fishing practices such as blast fishing and cyanide fishing are very dangerous, as they damage coral reefs badly and disrupt the subtle balance of the marine ecosystem.

• Coral Mining − Extraction of corals for construction and ornamental purposes has also put threats on coral reefs.

• Coastal Development − These days, numerous construction activities are going on in the coastal areas that directly and indirectly pollute the oceanic water and affect the growth and survival of corals.

Need for Conservation

As we have discussed that the coral reefs offer a favorable environment for numerous oceanic organisms and help to maintain a very rich and resourceful marine biodiversity. But because anthropogenic as well as some natural activities, its existence is in threat, which directly will damage the habitat of large number of marine species. Therefore, it must be conserved by −

Creating Marine Protected Areas − As we have national parks where any human activity is restricted (like hunting, tree cutting, etc.), similarly, it is required to create a protected zone in respective reef region. It will restrict the human activities and provides favorable environment coral to grow.

Restricted Fishing Practice − It is also required to educate fishermen and provide them proper technique for sustainable fishing practices. It will help to maintain the ecological balance in the region.

Reduction in Carbon Emissions − It is essentially required to reduce the emission of not only carbon but also some other greenhouse gases that directly responsible for the coral bleaching and acidification.

Coral Restoration − It is one of the most influential and effective techniques to restore the damaged reefs by coral transportation and propagation in respective region.

Conclusion

Coral reefs are one of the richest and diverse marine ecosystems that essentially required to maintain the marine ecological balance. The regions with coral reefs exemplify the extraordinary beauty and complexity of marine life. Because of this, the marine biodiversity and ecological significance keep greater importance. Therefore, by understanding the importance of their existence, it is essentially required to protect and conserves these coral reefs worldwide.

Frequently Asked Questions

What are coral reefs, and where are they found?

Coral reefs are underwater structures of coral polyps' accumulation over time. They are typically found in warm, shallow waters of tropical and subtropical regions around the world.

How do coral reefs support marine life?

Coral reefs, in fact, are biodiversity hotspots, as it provides favorable habitats for countless marine species. They offer shelter, food, and breeding grounds for various species including fish, invertebrates, and other marine organisms.

What is coral bleaching, and why is it a concern?

Coral bleaching is a process that occurs when corals expel the symbiotic algae (zooxanthellae). And, it happens because of rising sea temperatures. The coral bleaching leads to the loss of vibrant colors and can cause coral death, posing a significant threat to coral reef ecosystems.

What is the role of zooxanthellae in coral reefs?

Zooxanthellae are marine photosynthetic algae that live within coral tissues in a symbiotic relationship. Likewise, they provide essential nutrients to the corals through photosynthesis, supporting their growth and contributing to the health of coral reefs.

How do human activities impact coral reefs?

Unregulated human activities, in the present era, such as faulty or overfishing, coastal development, various types of pollution, and coral mining, all collectively can severely damage coral reefs and disrupt their delicate balance. In addition to this, climate change and ocean acidification further exacerbate these threats.

What are the consequences of coral reef degradation?

Coral reef degradation will directly cause loss of marine biodiversity and badly affect marine ecosystems. Besides, it also affects coastal communities that rely on reefs for fishing and tourism, eventually causing economic and social consequences.

What conservation efforts are in place to protect coral reefs?

Major conservation efforts that essentially required to conserve the coral reefs include establishing marine protected areas, promoting sustainable fishing practices, coral restoration initiatives, and addressing climate change by reducing carbon emissions.

Are coral reefs threatened by ocean acidification?

Definitely yes, ocean acidification, which is caused by increased carbon dioxide absorption in the oceans (released in the environment by various human activities), affects coral reefs’ health and restrain the growth of coral skeletons, making them more vulnerable to other threats.

Why are coral reefs called "rainforests of the sea"?

Popularly and commonly coral reefs are nicknamed as "rainforests of the sea," because it provides favorable environment to numerous marine species and likewise, helps in balancing the diverse ecosystem in the region, which is very similar the diversity found in terrestrial rainforests.