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
.
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.