Mangrove Methane Biogeochemistry in the Indian Sundarbans: A Proposed Budget

A comprehensive methane (CH₄) budget for the Sundarbans mangrove ecosystem reveals significant CH₄ production, transport, and atmospheric exchange. Intertidal sediments produce 3547 µmol m⁻³ wet sediment d⁻¹ of CH₄, with 8.2% advectively transported to adjacent estuaries—20 times more than diffusive flux. The study estimates 0.09 Gg yr⁻¹ of CH₄ released from Sundarbans estuaries to the regional atmosphere, while only 2.75% of forest atmospheric CH₄ reaches the upper atmosphere annually. Mean CH₄ mixing ratios over the forest were 2 ppmv, with photo-oxidation rates of 3.25 × 10⁻⁹ mg cm⁻³ d⁻¹. The research also identifies anaerobic CH₄ oxidation in mangrove sediments, contributing to a nuanced understanding of tropical mangrove biogeochemistry.

Dutta, M. K., Bianchi, T. S., & Mukhopadhyay, S. K. (2017). Mangrove Methane Biogeochemistry in the Indian Sundarbans: A Proposed Budget. Frontiers in Marine Science, 4. https://doi.org/10.3389/fmars.2017.00187