Forested coastal wetlands are globally important systems sequestering carbon and intercepting nitrogen pollu-tion from nutrient-rich river systems. Coastal wetlands that have suffered extensive disturbance are the targetof comprehensive restoration efforts. Accurate assessment of restoration success requires detailed mechanisticunderstanding of wetland soil biogeochemical functioning across restoration chrono-sequences, which remainspoorly understood for these sparsely investigated systems. This study investigated denitrification and green-house gasfluxes in mangrove and Melaleuca forest soils of Vietnam, using the15N-Gasflux method.Denitrification-derived N2O was significantly higher from Melaleuca than mangrove forest soils, despite higherpotential rates of total denitrification in the mangrove forest soils (8.1 ng N g-1h-1) than the Melaleuca soils(6.8 ng N g-1h-1). Potential N2O and CO2emissions were significantly higher from the Melaleuca soils thanfrom the mangrove soils. Disturbance and subsequent recovery had no significant effect on N biogeochemistryexcept with respect to the denitrification product ratio in the mangrove sites, which was highest from the youn-gest mangrove site. Potential CO2and CH4fluxes were significantly affected by restoration in the mangrove soils.The lowest potential CO2emissions were observed in the mid-age plantation and potential CH4fluxes decreasedin the older forests. The mangrove system, therefore, may remove excess N and improve water quality with low greenhouse gas emissions, whereas in Melaleucas, increased N2OandCO2emissions also occur. These emissionsare likely balanced by higher carbon stocks observed in the Melaleuca soils. These mechanistic insights highlightthe importance of ecosystem restoration for pollution attenuation and reduction of greenhouse gas emissionsfrom coastal wetlands. Restoration efforts should continue to focus on increasing wetland area and function,which will benefit local communities with improved water quality and potential for income generation underfuture carbon trading.
Tạp chí khoa học Trường Đại học Cần Thơ
Lầu 4, Nhà Điều Hành, Khu II, đường 3/2, P. Xuân Khánh, Q. Ninh Kiều, TP. Cần Thơ
Điện thoại: (0292) 3 872 157; Email: tapchidhct@ctu.edu.vn
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