Effects Of Sphagnum Mosses Degradation And Nitrogen Nutrition Environment Change On Carbon Cycle In Peatland, Greater Khingan Mountains

Peatland in China mainly distributes in the northern high latitude region, it is very sensitive to the change of the climate as a result of its special cold-wet environmental characteristics, especially under the impact of the permafrost. In the recent decades, the climate of the northern high latitude region warmed significantly, resulting serious degeneration of the permafrost. Bio-geochemical processes in carbon – nitrogen cycle have been impacted directly or indirectly by the climate warming and atmospheric nitrogen deposition which were induced by human activity. There has been a growing interest in carbon balance and carbon cycle in peatland ecosystem. But study on the effect of climate change on carbon cycle in continuous permafrost region in Greater Khingan Mountains is scarce. Therefore, a field experiment was established in peatland of permafrost region in Greater Khingan Mountains to simulate, both the effect of climate warming on sphagnummoss degradation by sphagnum moss removal, and the effect of atmosphere N deposition on nitrogen nutrition environment change by nitrogen input to study the effect of sphagnum moss degradation, nitrogen nutrition environment change and their interaction on CH4、CO2 and N2 O fluxes in peatland ecosystems in permafrost region. We obtained the following conclusions:(a) Sphagnum mosses removal significantly decreased CH4 fluxes by 50.4%, but did not change the temporal variation of CH4 emissions in peatland ecosystems. Nitrogen input significantly decreased the CH4 emissions by 65.8%. The interactive effect of Sphagnum mosses removal and nitrogen input significantly decreased the CH4 emissions by 68.5%. Soil temperature and moisture were the main factors affecting the CH4 fluxes in peatland ecosystems in permafrost region.(b) Sphagnum mosses degradation reduced CO2 fluxes(3.9%- 13.1%) in peatland ecosystem in permafrost region. Nitrogen input increased CO2 fluxes(12.7%- 46.8%) compared with the control treatment, but had not significant effect on the temporal variation of CO2 fluxes. The CO2 fluxes in peatland ecosystems increased by 21.6%- 35.9% under the interactive effect of Sphagnum mosses removal and nitrogen input. Soil temperature was the main factor affecting CO2 fluxes in peatland ecosystem.(c) The N2 O fluxes increased first by 11.1%- 115.4% and then decreased by 4.29% after Sphagnum mosses removal.Nitrogen input increased theN2O fluxes in peatland ecosystems by 47.5%- 85.1%, However, nitrogen input did not affect the temporal variation of the N2 O fluxes. The interaction of Sphagnum mosses removal and nitrogen input hugely increased the N2 O emissions by 36.7%- 78.9%. Thus, the N2 O emissions in peatland ecosystems were mainly affected by the up-ground biomass and nitrogen effectiveness.(d) Both Sphagnum mosses degradation and nitrogen input decreased the dissolved CH4 concentration in pore water. For dissolved CO2 concentration in pore water, Sphagnum mosses degradation decreased the concentration while nitrogen input increased it. The change of dissolved CH4 and CO2 concentrations in pore water was various at different depth under the interactive effect of Sphagnum mosses removal and nitrogen input.