The National Centre for Coastal Research (NCCR), Mandapam Field Research Centre, has said the recent blooming of ‘Noctiluca marine micro algae’ in the Gulf of Mannar (GoM) might have occurred due to discharge of ballast water from some cargo ships and vessels near the Sri Lankan coast.
Giving details of the preliminary study conducted by a team of NCCR scientists on ‘Noctiluca scintillans’ bloom in the GoM and the health of coral reefs in the Mandapam group of islands in the Gulf of Mannar Marine National Park, T. Shanmugaraj, Scientist F, NCCR, said, “We have concluded that the blooming might be due to discharge of ballast water.”
When there was no discharge of sewage or industrial waste into the sea in Mandapam region, and when there was a lack of rainfall, there was no possibility of mixing ‘agricultural runoff’ in the seawater, which could have increased the nutrient content of seawater, attracting micro algae, he said.
“Therefore, blooming between the GoM islands and Mannar islands off the Sri Lankan coast might have been due to release of ballast water into the sea from the Lankan coast,” he said.
A team of scientists from the Mandapam Regional Centre of the Central Marine Fisheries Research Institute, however, had said good organic condition in the seawater and high temperature in the region became conducive for the green algae to breed and release spores, which resulted in mass fish deaths and seawater turning green.
Quoting NCCR scientists, Mr. Shanmugaraj also said the blooming had not affected coral reef colonies in the Mandapam group of islands. Citing the monitoring data on corals in natural coral reef environment and restoration sites, he said, “We did not find any negative impact of stress and mortality on coral reefs.”
T.P. Ashok Kumar, Wildlife Warden, GoM Marine National Park, who inspected the coral colonies after the blooming along with scientists, said coral colonies in Shingle island were found dead. The blooming, however, had no or little impact on Kurusadai island, he said. The Reef Research Team of of Suganthi Devadason Marine Research Institute had said the blooming had killed about 180 coral reef colonies in Shingle island.
