A busy continuous navigation in this region will offset and trigger devastating ecological imbalance, affecting the lives of millions of fishermen and many endangered organisms of the subtropical, shallow Gulf of Mannar.

Sethusamudram Ship Canal Project (SSCP) will link the Gulf of Mannar and Palk Bay in the southeastern coast of India. This economically and environmentally crucial mega project to change the face of regional shipping has been initiated after being cleared by the Environment Ministry and Cabinet Committee. This 360 km long and 300 m wide shipping canal will provide a continuous navigable route cut through Adam’s Bridge, a natural chain of shoals to avoid circumnavigating Sri Lanka.

Ecological balance during and after completion of the project

On completion, the canal will save 20 h of ship journey and considerable amount of fuel. But a busy continuous navigation in this region will offset and trigger devastating ecological imbalance, affecting the lives of millions of fishermen and many endangered organisms (fishes, coral reefs, sea horses, algae and other marine plants) of the subtropical, shallow Gulf of Mannar. The Gulf of Mannar and Palk Bay support a delicate ecosystem, with the second highest marine biodiversity on the earth. The Palk Bay is already on the verge of ‘Jivânikhâtanam’ (a process that will entomb/endanger marine organisms).

Is our pre-SSCP assessment of environmental impact adequate and correct?

The scheme should have been put through after a well-informed and many-sided debate, a common rule of developmental prudence. The United States Environmental Protection Agency (USEPA) has developed useful guidelines for evaluating ecological indicators that include conceptual relevance of ecosystem function, feasibility of implementation, response variability in time and space, and ability to convey information on ecological condition that is meaningful for resource management. Instead, the National Environmental Engineering Research Institute (NEERI), Nagpur has approved the project after a rapid Environmental Impact Assessment (EIA).

Evaluation of the environmental/ecological impact of a maritime project is based on a detailed study of geological, biological, physical and chemical oceanographic parameters. These factors play an important and collective role. If any one of these factors is stressed beyond the manageable and threshold limit, the system gets affected adversely beyond repair. Turbidity (suspension of clay and mud in water column) is one such factor. This could be fatal to an ecosystem. Unfortunately, according to an estimate, SSCP dredging may displace around 9.7 million m3 bulk of rock, shoal and sediments, making the water column highly turbid till the project is completed. The operation will displace/release a few hundred thousand tons of clay-size particles (dumping of this is another major issue). The stressed turbidity causes imbalance in O2–CO2 ratio, imperative for life and health of phytoplanktons, which are the lowest in the marine ‘food chain’. Moreover, if this kind of turbidity continues for a long duration (till completion SSCP), penetration of sunlight below 2–3 m depth will be blurred. This will check the photoinhibitation and lower the pH of water (more acidic) as CO2 supply will continue due to respiration of animals, while release of O2 will diminish amidst the slow pace of photosynthesis. This process will encourage abundant growth of anaerobic organisms and may worsen the health of other organisms.

Are coral reef stressed?

Coral reefs, the land-bridging platforms and lungs of the shallow oceans, are at decline worldwide due to anthropogenic impact/activity. Coral reefs are bioherms that favour high biodiversity vis-à-vis supporting standing crop of phytoplanktons. Like tropical rainforests, coral reefs have evolved complex interdependent community structures despite or more likely, because of paucity of nutrient resources in their environments. The turbid conditions that SSCP is likely to cause will harm and destroy corals within a short span of time.

In a way, the whole environment in the Gulf of Mannar and Palk Bay is at stake and life from micro- to macro-levels, like fishes, corals, sea horses, sea cows and many species of marine plants is endangered, including those living around Shingle Island and Van Tivu Island, both of which are situated within the Gulf of Mannar Marine National Park, widely known for its biodiversity. The proposed canal will pass 20 km away from the Shingle Island and 6 km from the VanTivu Island.

What needs to be carried out?

A multilevel approach to monitor the marine ecosystem and evaluate the risk assessment of the region needs to be carried out. Risk assessment data should be collected from satellite imageries to molecules. Environmentalists must evaluate the measures required to protect the two important warm, subtropical marine ecosystems of the Bay of Bengal and the Indian Ocean. The data collected will provide the environment managers with affordable procedures to minimize the impact of the
Sethusamudaram project on the regional environment and also safeguard the biodiversity of the region to the extent possible. Furthermore, the area is vulnerable to tsunamis. The project needs to be evaluated for post-disaster management.

Indian Academy of Sciences - http://www.ias.ac.in/