Coral reefs - the rainforest of the sea

“A thick forest rich in biodiversity, found typically in tropical countries with consistently heavy rainfall.”

Any guesses on what I am attempting to convey here? Alright, what comes to your mind, when I say Amazon? No, no, not your favourite online shopping portal, I am talking about the Amazon forest! Yes! It is Rainforest, which is known for its rich species diversity. Be it, animal, birds, plants, insects or even micro organisms, it harbours it all. Yes indeed! But there is a twist in the tale folks. This blog is all about the rainforest, but not about the one which is land-based. Confused? Actually, there is something known as rainforest of the sea. Guess what?

Coral reef (en.wikipedia.org)

It is Coral reefs. Corals are beautiful marine organism possessing the characteristics of both plants and animals. Zooxanthellae and polyps are plants and animals respectively. The polyps absorb calcium and carbonate ions from the seawater and produces calcium carbonate i.e. limestone. And this limestone forms its outer protective skeleton, coral. Along with other corals, they form colonies called ‘coral reefs.’ These reefs are colourless when produced, then where does it get its vibrant colour. That is where the plant, Zooxanthellae’s role comes into account. Zooxanthellae produce a pigment from itself, resulting in colourful coral reefs.

Coral reefs are shallow water, tropical marine ecosystems. Diversity is unequalled by any other habitat. Coral reef supports a variety of sea life. They are nursery of 4,000 species of fish. Young fish find safety in this environment. Shoals of tiny vibrant and colourfully patterned fishes scuttle in and out of coral branches. Around 75% of coral reef fishes rely on live corals for food, shelter or settlement. Some of these fish feed on algae, keeping corals from being suffocated by them. Because most of the algae that grows in corals are toxic, in turn affecting their livelihood. Sharks, manta rays, sting rays and other predatory fishes keep populations of smaller fishes and other organisms in check.

Parrotfish in corals (www.earthsky.org)

Amazed by the lovely sand beaches present across the shores? Thank parrotfish! It is present across the corals. They feed upon the tiny algae, zooxanthellae, living inside the coral polyp. They scrap the corals and get into it to feed on zooxanthellae, then grind up the coral skeleton and excrete it as sand. This results in the establishment of the beautiful sand beaches.

Threats that affect their survival

As you know, zooxanthellae are responsible for the coral’s vibrant colour. This when expelled from the corals leads to whitening of corals. It happens when there is an increase in sea temperature or pollution due to human interference. This phenomenon is referred to as coral bleaching. Meanwhile, Oceans absorb atmospheric CO₂ resulting in a decrease in the pH level of the ocean, what has come to be called as ‘acidification of the sea’. Once the ocean is acidified, its alkalinity starts falling, so does the concentration of calcium and carbonate ions. And if there is less concentration of calcium and carbonate ions, how do the coral polyps perform its role of producing outer skeleton? Therefore, global warming also causes coral bleaching.

Why should we protect Corals?

Corals have intrinsic ecological as well as economic value. It harbours a large range of biodiversity starting from phytoplankton, the first item in the food chain (8^th STD Biology), to the large predatory organisms like sharks and rays. It as well serves as a massive breeding site for several marine organisms. Apart from that, it protects our coast, like a giant wall of china, from natural cataclysms. The annual value of the ecosystem services provided by coral reefs to millions of people is estimated to be over 5.98 lakh crore.

Now tell me is it not worth conserving corals?

I am working on the follow up article which is on the Conservation of coral reef, so don’t forget to visit Creatikaa again.