Sundarbans under threat

The Sundarbans, located in the delta region of the Ganges-Brahmaputra river system, is one of the largest mangrove ecosystems globally and serves as a crucial habitat for diverse flora and fauna, including endangered species.

The Sundarbans, located in the delta region of the Ganges-Brahmaputra river system, is one of the largest mangrove ecosystems globally and serves as a crucial habitat for diverse flora and fauna, including endangered species.

However, it is under threat. The threat is from air pollution.

A new study conducted by researchers from Indian Institute of Technology Kanpur and Bose Institute, Kolkata has revealed how huge amounts of pollutants, mainly enriched with black carbon or soot particles, arrive from not only Kolkata metropolis but the entire Indo-Gangetic Plain (IGP) region, are significantly deteriorating Sundarbans.

“In coastal ecosystems, the mangroves usually form a series of antioxidants and reduce ROS and toxic stresses. However, prolonged and long-term deposition of heavy metals could affect their resistibility, causing cellular damage of mangroves,” explained Prof Abhijit Chatterjee, adding that such high ROS levels can harm the mangroves as well as aquatic animals by creating toxic conditions.

The study published in Elsevier, states that, surprisingly, the oxidative stress due to PM 2.5 pollutants in the Sundarbans – despite being sparsely populated – is as severe as in many urban areas.

“Our research clearly indicates that the transported and regionally emitted air pollutants have a significant effect on the ecology and biogeochemistry of the pristine environments of the Sundarbans mangrove ecosystem that need to be solved with utmost priority,” Prof Chatterjee said.

The team investigated the effect of aerosol acidity on the oxidative potential of the mangrove ecosystem.

The Sundarbans face a complex array of challenges affecting their air quality, including their unique geographical position, diverse weather patterns, socioeconomic factors, and the transport of pollutants from neighbouring metropolises, compounded by local emissions from nearby villages. Particularly during the winter, these factors contribute to a significant decline in air quality, posing a formidable obstacle to formulating effective pollution control policies for the region, which is home to 4.5 million inhabitants.

The Sundarbans mangrove ecosystem serves as a crucial player in mitigating climate change by acting as a net absorber of greenhouse gases, thereby aiding in their removal from the atmosphere. Its capacity to sequester atmospheric carbon and other warming gases surpasses even that of the Amazon rainforest.

Professor Chatterjee pointed to the pivotal role of the Sundarbans mangrove ecosystem in preserving the delicate equilibrium between the mangroves and the Bay of Bengal. He highlighted that stress induced by air pollution disrupts this equilibrium, compromising the ecosystem's resilience in shielding against tsunami-like events and safeguarding the Kolkata metropolis.