EGU21-1619, updated on 03 Mar 2021
https://doi.org/10.5194/egusphere-egu21-1619
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The role of land-use change and restoration on nitrogen processing in tropical coastal wetlands of Vietnam

Sophie Comer-Warner1, Anh Nguyen2, Minh Nguyen2, Manlin Wang1, Antony Turner1, Fotis Sgouridis3, Stefan Krause1, Hue Le4, Nicholas Kettridge1, Nghia Nguyen5, and Sami Ullah1
Sophie Comer-Warner et al.
  • 1University of Birmingham, Birmingham, United Kingdom of Great Britain – England, Scotland, Wales (s.comer-warner@bham.ac.uk)
  • 2Faculty of Environmental Sciences, University of Science, Vietnam National University, Ha Noi, Viet Nam
  • 3School of Geographical Sciences, University of Bristol, Bristol, UK
  • 4VNU-Central Institute for Natural Resources and Environmental Studies, Ha Noi, Viet Nam
  • 5Department of Soil Sciences, College of Agriculture and Applied Biology, Can Tho University, Can Tho City, Viet Nam

Coastal wetlands, including mangrove and melaleuca forests, are globally important due to their capacity in sequestering carbon and nitrogen, and intercepting nutrient pollution from vast, nutrient-rich, tropical riverine networks. Despite this, the environmental drivers controlling soil biogeochemistry in these ecosystems remain poorly understood. Here we conducted a study across gradients of restoration and land-use in the mangrove forest of Xuan Thuy National Park in the Red River Delta, northern Vietnam and the melaleuca forest of U Minh Thuong National Park in the Mekong River Delta, southern Vietnam. We investigated nitrogen transformation processes and greenhouse gas production in mangrove and melaleuca forest soils using a 15N-Gas flux method to determine rates of denitrification, and its relative contribution to soil N2O emissions. We found that denitrification was a more dominant source of N2O in the melaleuca soils, despite higher rates of denitrification in the mangrove soils resulting from more complete denitrification in the mangroves. N2O and CO2 emissions were significantly higher from the melaleuca soils. Disturbance and subsequent recovery or restoration of these forests did not have a significant effect on soil biogeochemistry. The mangrove system, therefore, may remove excess nitrogen and improve water quality while maintaining low emissions of greenhouse gases whereas melaleucas process nutrients at a cost of N2O and CO2 emissions. Melaleucas, however, may act as a significant CH4 sink at least partially balancing these emissions.

How to cite: Comer-Warner, S., Nguyen, A., Nguyen, M., Wang, M., Turner, A., Sgouridis, F., Krause, S., Le, H., Kettridge, N., Nguyen, N., and Ullah, S.: The role of land-use change and restoration on nitrogen processing in tropical coastal wetlands of Vietnam, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1619, https://doi.org/10.5194/egusphere-egu21-1619, 2021.