SUNDARBANS MAY BE LESS ‘BLUE’ THAN IT SEEMS

NEWS: Microplastics are altering the food web and carbon cycle in the Sundarbans–> Study published in Journal of Hazardous Materials Advances.

About the Sundarbans

• Sundarbans = World’s largest contiguous mangrove forest
• Located at the confluence of rivers: Ganga, Brahmaputra
• Receives huge waste inflow from upstream regions

Microplastics

• Tiny plastic particles (<5 mm)
• Originate from: Plastic waste breakdown, Synthetic fibres (clothes)

Key Findings of the Study

High Concentration of Microplastics

• 5 to 58 particles per litre of water
• ~40% higher during monsoon –> Due to runoff carrying plastic waste

Types of Microplastics

• Fibres (major) → from textiles
• Fragments (second)
• Common materials: Polypropylene (packaging), Polyethylene terephthalate (PET) (bottles)

Breakdown into Nanoplastics

• Plastics show: Cracks, pits, groovesà Indicates breakdown into even smaller nanoplastics
• Formation of “Plastisphere”à Microplastics host: Bacteria & microbesà These communities = Plastisphere

Impact on Carbon Cycle

• Plastics as Carbon Sourceà Plastics are ~90% carbon: Act as a “novel carbon reservoir”
• Release of Carbonà Microplastics release: Dissolved Organic Carbon (DOC)= Feeds microbes, Increases bacterial growth
• Biogenic Carbon Productionà Microbes on plastic produce: Biogenic carbon

Impact on Blue Carbon Ecosystem

• Mangroves = Blue Carbon Ecosystems–> Efficient at absorbing & storing CO₂
• Problem: Extra carbon from plastics: Disturbs natural carbon balance, Reduces efficiency of carbon sequestration