Effects of nitrogen and sulphate addition on methane oxidation in the marsh soil of a typical subtropical estuary (Min River) in China

ABSTRACT

Methane (CH₄) oxidation plays an important role in regulating the atmospheric CH₄ balance. Although nitrogen (N) enhancement and sulphate () deposition are major environmental problems facing the Min River estuary in subtropical China, the interactive effects of N and on CH₄ oxidation remain poorly understood. We conducted an incubation experiment to investigate the effects of N and additions on CH₄ oxidation in marsh soils. CH₄ oxidation exhibited distinct seasonal variations, which correlated with changes in temperature and soil moisture; in addition, CH₄ oxidation rates were enhanced by the addition of nitrate (), but were slightly inhibited by the addition of ammonium () and . The combined effects of N and on CH₄ oxidation were controlled primarily by the form of N, which may imply that inhibition of CH₄ oxidation with addition may be counteracted by N addition, especially in estuarine marsh soils with low N and high concentrations. We propose that, although was more effective in stimulating CH₄ oxidation and the inhibition caused by and was minor, CH₄ oxidation may be inhibited because was dominant and accompanied by strong deposition in the Min River estuary. As such, future CH₄ emissions from estuarine wetlands may increase as a result of higher inputs of and .

KEYWORDS:

• Methane oxidation
• nitrogen enhancement
• sulphate deposition
• marsh soil
• Min River estuary

Acknowledgements

M.J.H. and C.T. conceived and designed the study; M.J.H. and J.F.H. performed the experiment and all statistical analyses; M.J.H. wrote the manuscript; and B.J.W., Z.G.S., and C.T. assisted in interpreting the results and revising the manuscript. All authors reviewed the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Minjie Hu, Ph.D., mainly engaged in greenhouse gas emissions and nutrient cycling in wetlands.

Benjamin J. Wilson, Ph.D., mainly engaged in greenhouse gas emissions and biogeochemical cycles in coastal wetlands.

Zhigao Sun, professor, mainly engaged in greenhouse gas emissions and sulfur cycle in coastal wetlands.

Jiafang Huang, Ph.D., mainly engaged in methane transmission.

Chuan Tong, professor, mainly engaged in methane emission and its mechanism.

Additional information

Funding

Financial support for this study was provided by grants from the National Science Foundation of China (No. 41371127), the Key Foundation of Science and Technology Department of Fujian Province (No. 2016R1032–1), and the Program for Innovative Research Teams of Fujian Normal University (No. IRTL1205).