Sundarbans may be less blue than it seems, PgII

Key Highlights:

• Researchers from IISER Kolkata found that microplastics in the Sundarbans interfere with the natural food web and alter the carbon budget of the Bay of Bengal.
• The study, conducted between October 2021 and October 2022, revealed microplastic concentrations ranging from 5 to 58 particles per liter in the Mooriganga estuary.
• Microplastic levels were about 40% higher during the monsoon season due to rainfall washing plastic waste into the estuary.
• The most common microplastics found were fibers (likely from textiles) and fragments made of polypropylene and polyethylene terephthalate.

Detailed Insights:

• The Sundarbans, the world’s largest contiguous mangrove forest, accumulates waste from major rivers like the Ganga and Brahmaputra.
• As microplastics break down, they release dissolved organic carbon and support biogenic carbon production by microbes, acting as a novel carbon reservoir.
• High-resolution imaging showed that microplastics had cracks and grooves, indicating breakdown into nanoplastics, and hosted complex microbial communities called plastispheres.
• The introduction of carbon via microplastics could reduce the efficiency of mangroves as blue-carbon ecosystems, which naturally capture and store atmospheric carbon dioxide.

Key Concepts Involved:

• Microplastics: Small plastic particles less than 5mm in size resulting from the degradation of larger plastic items.
• Blue-Carbon Ecosystems: Coastal ecosystems like mangroves and tidal marshes that efficiently capture and store carbon dioxide.
• Carbon Budget: The balance of carbon fluxes between the atmosphere, oceans, land, and living organisms.