Indian marine scientists from the Zoological Survey of India (ZSI) found a dead coral reef from 10,000 years ago in the Gulf of Kutch, and decided to try and revive it. Corals were then transplanted from a similar environment in the Gulf of Mannar and these fragile creatures survived. Given the marine environment in the Gulf of Kutch, the scientists now intend using the region as a sanatorium for sick and stressed out corals.
The beginning of this story dates back to over 10,000 years ago when there was a large thriving coral reef in the Gulf of Kutch. The reef had a good diversity of stony corals and was dominated by Acropora Stag-horn branching corals. Sediments brought down by the rivers that flow through the Kutch area caused silt to settle on the coral beds, leading to the death of these branching corals.
Indian marine scientists found dead branching corals on the 42 islands around the Gulf of Kutch. Carbon dating enabled them to deduce that these branching corals had died some 10,000 years ago.
Dead Acropora Stag-horn corals strewn across an island
These scientists from ZSI did not leave the story unfinished here. “Through our various studies we have found that the sediment load flowing into the Gulf of Kutch, especially from the Indus river, has reduced due to the construction of dams and hence we decided to bring back to life the long vanished coral reef by transplanting the Acropora Stag-horn corals; they grow fast when compared to other coral species and help in increasing the fish population,” says Dr Ch. Satyanarayana, Scientist and Coral Taxonomist with ZSI.
India has four major coral reef regions – in the waters around the Andaman and Nicobar islands, the Lakshadweep islands, the Gulf of Mannar, and the Gulf of Kutch. Indian scientists have vast experience diving and carrying out research in reef regions around the country and around the world – they found that the environment in some parts of the Gulf of Mannar and the Gulf of Kutch is very similar.
So, they decided to restore the reef in the turbid waters of Kutch by transplanting corals from the waters of Mannar, which, to their surprise, was a success.
“This is for the first time in the world that biologists have managed to restore a reef that has been dead for thousands of years by transporting live corals from more than 2,000 km away and growing them in turbid waters,” says Dr. Kailash Chandra, director of ZSI.
One square km of the coral reef has been restored at the Marine National Park in the Gulf of Kutch. A technique similar to grafting new rose bushes, with twigs delicately taken from the mother plant, was used to restore this coral reef.
Corals are marine invertebrates that live in compact colonies. They are generally found in tropical waters and require a pristine environment to live and grow. Corals secrete a calcium carbonate skeleton for their own protection. Along with other calcium-secreting marine creatures, they form mountain-like structures underwater, which are called coral reefs.
Coral reefs are called ‘rain forests of the sea’ because of the diversity of life they harbour. They are home to many species of fish, support tourism, and are a huge resource for the pharmaceutical industry. They are indicators of climate change and act as a first line of defence against cyclones and tsunamis.
“Corals are primitive animals, they have no heart or circulatory system. The water they live in must be clear so that sunlight penetrates. Corals have a photosynthetic algae which lives in their tissues, called zooxanthellae,” continues Dr Satyanarayana.
The zooxanthellae supply the coral with food, produce oxygen and help it eliminate waste. In turn, the coral gives, the algae a protected environment to live in and all the compounds they need for photosynthesis.
The project to study the coral reefs in Indian waters, which led to the transplantation of the Acropara corals in the Gulf of Kutch, was started in 2012 and is slated to go on till 2017. It is being funded by the World Bank. The scientists working on this project find it really interesting that the corals that have been transplanted from the Gulf of Mannar have survived and are thriving in the murky waters of the Gulf of Kutch.
“During the transportation of coral fragments from the donor site to the recipient site, utmost care had to be taken to make sure that the salinity, the pH level, the temperature and the oxygen level of the water, were exactly the same. We have used ‘jel ice’, which is usually used to preserve flowers, when transporting the corals from one end of the country to the other,” explains Dr Satyanarayana.
A qualified scuba diver himself, Dr Satyanarayana is being supported in this underwater project by Australian scientist Dr Carden Wallace, a world renowned Stag-horn coral expert, who had earlier trained him in coral taxonomy in the Museum of Tropical Queensland at Townsville, Australia. She was instrumental in helping him make the choice of corals to transplant to the Gulf of Kutch.
Given the success of this mission, ZSI scientists are seriously considering setting up a coral sanatorium in the Gulf of Kutch, for sick and stressed out corals from around the country.
“Rising temperatures of waters are causing many corals to get sick, which is called coral bleaching. We discovered that the corals of the Gulf of Kutch are less affected by global warming, when compared to other reef regions in the country. The sediments suspended in the waters help to give shade to the corals below, protecting them from the direct and harsh rays of the Sun. This helps corals in well circulated turbid water to have a better chance of survival when compared to corals growing in clear water,” says India’s coral expert.
Owing to global warming, heavy sedimentation and the increasing contamination level of water, many corals are dying around the world. Few people are aware of this problem, consequently there is not enough effort being made to save them. Much more awareness about corals and their usefulness to us has to be spread if these precious life forms are to be saved. . Since reefs are helpful to protect us from various natural hazards, it is for us to take care and protect them.