Chennai: Destruction of coral reefs raises tsunami fears

CHENNAI : Chennai has become vulnerable to tsunamis and cyclones following the destruction of coral reefs, which are nature’s defence against such disasters, said director of the Zoological Survey of India K Venkatraman.Speaking on the sidelines of a function organised to mark the International Day for Biological Diversity he told City Express that Chennai had been rendered vulnerable by the destruction of the city’s coral reefs that acted as a protective barrier.  “Coral reefs, also known as the rain forests of the seas, are the frontline protectors followed by mangroves, which Chennai does not have. And that is the reason why the city was affected by the tsunami and had such high casualties when the cyclone hit the coast,” said Venkatraman.S Balaji, chief conservator of forests and trust director of the Gulf of Mannar Biosphere Reserve Trust, said that the tsunami did not impact the Gulf of Mannar as much as it affected Chennai since the region was shielded by coral reefs and mangroves. He added that Cuddalore, whose coral reefs have been destroyed, was also badly hit.Coral reefs are found in shallow waters with an ideal temperature range between 20 and 30 degree celsius. They are structures that have been formed over hundreds, thousands or even millions of years by tiny organisms called polyps, which produce skeletons of calcium carbonate.The reef-building corals contain symbiotic, microscopic, photosythesising algae called zooxanthallae. While the polyps provide the algae with carbon dioxide, the algae uses sunlight to convert it into oxygen.Braulio Ferriera de Souza, executive secretary of the Secretariat to the Convention on Biological Diversity, warned that if no steps were taken to protect the reefs that were slowly dying, they would be the first eco-system to disappear from the world.He explained that reefs around the world are subject to thermal stress, which is regular bleaching from warmer temperatures. Coral reefs aren’t made to recover from such chronic exposure. He highlighted greenhouse gases as damaging factors for the reefs. The increased CO2 from these gases that settles in the oceans alters the chemistry of the water, making it more acidic, thereby more harmful to the reefs.