The spiralling concentration of carbon dioxide in the atmosphere and our oceans have led to global warming. The marine life has been severely affected by climate change. Marine environmental issues like ocean acidification, ocean deoxygenation, sluggishness in ocean currents continue to deteriorate marine ecosystems which are not only home to a range of animal and plant species but are also responsible for half of the oxygen on our planet. One of the major issues that the rising temperature of the ocean water has resulted is the declining coral life, the phenomenon known as, coral bleaching. This has put coastal communities and infrastructure at risk of large scale damage. Driven by carbon pollution, warming ocean water have been contributing to coral bleaching which has become a global crisis. The coral polyps, triggered by warmer water, expel out algae which reside in their tissue in an endosymbiotic relationship. This expulsion of colourful algae, which are vital for the health of coral and its reefs, from the corals makes them white or bleached and leaves them more vulnerable to several diseases. With a stunted growth and reduced reproduction capabilities, the decline in coral health impacts other species too which rely on these coral communities for their shelter, food and breeding environment.
Being an important part of the ecosystem, the corals are crucial for coastal communities when it comes to their food security and providing a natural guard or barrier to shorelines against storms, floods and tides, thus, preventing damage to coastal properties and loss of lives. As far as half of the tropical fish in the world come from coral reefs. In recent years, we have seen a massive decline in tropical fish and coral bleaching could be one of the major causes. The simple fact is as the corals die, the reefs die and erode too with the time, which, in turn, destroys the breeding and feeding environment for a wide range of species. Blast fishing, an anthropogenic activity, which is also illegal in most parts of the world, used to stun or kill schools of fish using explosives so that they can be collected easily can destroy coral reef ecosystem.
The Great Barrier Reef in Australia, one of the UNESCO’s world heritage sites, saw the death of more than a third of corals in the reef by back to back marine heatwaves between 2016 and 2017. Historically, the bigger bleaching events used to occur every twenty-seven years, however, with global warming, now, it occurs once in every six years. Scientists warn that if we do not curtail our carbon emissions, the Great Barrier Reef could witness mass coral bleaching every two years; and globally, it is estimated that bleaching will have impacted most of the reefs of the world by 2050.
The coral reefs have immeasurable value not just in terms of biodiversity but they also provide huge value to national economies. The efforts are being made to preserve the coral reefs around the world. Earlier, more emphasis was on the natural restoration of the damaged reefs but now a greater human intervention is needed. Millions of coral larvae, raised in labs, have been seeded in the damaged patches of the Great Barrier Reef. However, experts opine that to reverse coral bleaching, the most effective and surest way is to reverse global warming!