A Guide To Corals

Basics on the embellishments of the oceans

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ILLUMINATION’S MIRROR

5 min readJun 26, 2022

If one were to ask an average high school student what they know about corals, they would probably describe a hard, ambiguously shaped skeletal object that comes in a variety of bright colours and is found on the Great Barrier Reef, along the coasts of Australia.

I say this because as a teenager with limited knowledge, I too related corals with ‘brightly coloured objects’ and ’Australia’. With age, lessons and the consequently accrued wisdom, I began to associate them with words like ‘UNESCO’ and ‘Heritage Site’ and today as an aspiring environmentalist, with a very heavy heart I add the words ‘Critically Endangered’ to this record.

Estimated to have first appeared in the Cambrian Period about 535 million years ago, corals are renowned for being uniquely shaped and coloured and tourists are often tempted to take them home as a memoir of their seaside holidays, blissfully unaware that they’re committing a potential felony that could land them in jail for up to 7 years in countries like India. Yes, 7 years. Interestingly, that’s also the maximum term of punishment prescribed for kidnapping, as per Section 363 of The Indian Penal Code,1860.

It should be noted though, that corals find value in more venues than home decor. Attractive as they are, corals are immensely prized in the jewellers’ community, which is a core participant in their unlawful sale and purchase that amounts to an estimated $230 million of illegal wildlife trade. To safeguard these endangered marine animals, many countries and intergovernmental organisations have enacted laws providing varying degrees of protection to them.

For instance, Australia, which has the worlds largest coral reef system, has enacted the Great Barrier Reef Marine Park Regulations, 2019 which makes provision for and in relation to the establishment, control, care and development of a Marine Park in the Great Barrier Reef Region. In India, corals are protected under Schedule I of the Wildlife Protection Act,1972 which grants them the same level of protection as a tiger or a leopard. Red, pink and other coral species in the genus Corallium of corals are afforded protection from over-exploitation by the Convention on International Trade in Endangered Species (CITES).

However, the most important reason for awarding corals such a high degree of protection is their significance to the environment and consequently man’s existence. As per the Status of Coral Reefs of the World: 2020 report produced by the Global Coral Reef Monitoring Network (GCRMN), corals support at least 25% of marine species and underpin the safety, coastal protection, wellbeing, food and economic security of hundreds of millions of people. The value of goods and services provided by coral reefs is estimated at $2.7 trillion per year, including $36 billion in coral reef tourism.

Inspite of the existence of multiple laws to protect them, the number of corals present in marine ecosystems has been dwindling, owing particularly to anthropogenic activities. Global warming and climate change have caused the average temperature of the earth and water bodies to rise, which has been detrimental to coral health. They have caused “coral bleaching”, which has led to an estimated loss of 14 percent of the world’s coral reefs over the past decade. According to the National Oceanic and Atmospheric Association, between 2014 and 2017 around 75% of the world’s tropical coral reefs experienced heat-stress severe enough to trigger bleaching.

Now that we have an idea about the relevance of corals and the legislations in place for them, let us delve into the basics and understand what exactly corals are, the types to exist in nature and the phenomenon of coral bleaching.

What is a coral?

Simply put, corals are marine invertebrate animals belonging the phylum Cnidaria. Each coral animal is called a “polyp”, and they usually multiply into genetically identical copies and form colonies. Inside these polyps, microscopic algae called Zooxanthellae live. Zooxanthellae are of many kinds and give the corals their unique colours. They have a mutualistic relationship with corals, wherein the coral provides the zooxanthellae shelter, while the latter provides the coral organic minerals which it uses to synthesise its skeleton.

Types of Corals

Corals are broadly classified into two types:

i. The stony, shallow-water corals that we commonly see in relatively warm waters of about 22–29°C. They build colonies or reefs, and create skeletons out of calcium carbonate, a hard substance that eventually becomes a rock. There are hundreds of species of this type of coral, and they recover faster than their deep water counterparts.

ii. The soft, deep-water corals that live in dark cold waters, upto a depth of about 6,600 ft, in temperatures as low as 4°C. They do not need sunlight and live by trapping small organisms around them. They grow more slowly and have fewer species than their shallow water counterparts.

What is Coral Bleaching?

Coral Bleaching is when corals come under stress due various factors called ‘stressors’, and expel the zooxanthellae living in them. The absence of the algae gives it a ‘bleached’ appearance and the continued action of the stressor eventually leads to the coral’s death. ‘Stressors’ primarily include sea water that is hotter than usual and chemical pollution of the sea, ocean acidification and extremely low tides among others.

Royalty Free Image Of Coral Bleaching from iStockphoto.com

Possible cure/solutions?

Scientists from all over the world are coming up with innovative solutions to control the phenomenon of coral bleaching.

One that has caught the attention of many is coral restoration through “Biorock Technology”. This method applies safe, low voltage electrical currents through seawater, causing dissolved minerals to crystallise on structures, forming white limestone similar to that which naturally makes up coral reefs and tropical white sand beaches. The rate of growth is much faster than the coral’s actual growth rate and it requires corals to use much lesser energy. This technique has been implemented in the Gulf of Kutch in India.

Another innovative solution was put forward by a group of scientists in Australia who made the coral more tolerant to temperature-induced bleaching by bolstering the heat tolerance of its micro-algal symbionts. They found that “the heat-tolerant micro-algae are better at photosynthesis and improve the heat response of the coral animal”. The next step of the experiment is to apply this principle onto a variety of corals and algae and determine whether this technique can be applied universally on all species of corals.

Though these solutions bode well for the corals, the core issue of man’s irresponsible behaviour towards his environment still remains. Unmindful anthropogenic activities are leading to the destruction of the Earth, and our approach must change. Educating people about sustainable and eco-friendly activities should be a priority and implementing policies such as use of renewable energy over fossil fuels and setting net zero targets should be the norm.

We have been finding ourselves in do or die situations too often now, where we are racing against time to save the earth. Let us try to change this and live harmoniously with our planet and all of its creations.

References:

A Guide To Corals

Basics on the embellishments of the oceans

Written by Vidushi