Marine Debris Damaging Coral Reefs: NIO Scientist

Among the four major types of marine pollution — chemical pollution, nutrient pollution, marine debris pollution and air pollution, chemical and nutrient pollution play major role to obstruct the role of corals.

Pesticides containing persistent organic pollutant (POPs), hydrocarbons from oil tankers and heavy metals from industrial (mining, dredging) effluent cause major threat to corals, the scientist said.

Some coral species are sensitive to these although the extent is not yet known, Dr. Saha said.

Toxic chemicals like POPs and PAHs can destroy or damage reef communities by affecting coral’s reproduction and growth and can be bio-magnified to a critical level for the higher level animals of the food chain making them vulnerable to this process, the workshop was told.

Heavy metals such as copper and zinc have been linked to reduced fertilisation, fecundity and growth in adult corals.

Dr. Saha said nutrients discharged in form of fertilisers, waste feed and other materials from aquaculture and agriculture into coastal waters which lead to the bloom of nuisance algae (eutrophication) and subsequent oxygen depletion, plays a major hindrance in coral growth.

She pointed out that according to World Resource Institute, Washington, the Southeast Asian coral reef including Indian Ocean, are in high risk in terms of human activities.

The percentage of inland pollution and marine pollution is also very high in these regions.

“However, inspite of corals and other marine ecosystem are at higher risk with the effect of marine pollution, not much work on effect of pollution have been done so far. Hence, more studies have to be done on quantity and quality of chronic pollutant discharge such as on corals. And also long term studies are needed to document the recovery times of reef from sewage impact,” she added.