Responses of greenhouse gas emission to simulated nitrogen deposition in Calamagrostis angustifolia wetlands of Sanjiang Plain, China.

A long-term simulated nitrogen deposition experiment was carried out in Ecological Locating Research Station of the Institute of Nature and Ecology of Heilongjiang Academy of Sciences, with three different treatments including low nitrogen treatment (40 kg N·hm-2·a-1), high nitrogen treatment (80 kg N·hm-2·a-1) and the control (0 kg N·hm-2·a-1). The greenhouse gas emission fluxes were measured using a static box-gas chromatography method, with environmental factors being simultaneously investigated to understand the responses of greenhouse gas emission to the nitrogen deposition in the Calamagrostis angustifolia wetland. The results showed that low and high nitrogen treatments significantly increased the greenhouse gas emission fluxes. The CO2 emission flux increased by 47.5% and 47.9%, the CH4 emission fluxes increased by 76.8% and 110.1%, and the N2O emission fluxes increased by 42.4% and 10.6% in low nitrogen treatment and high nitrogen treatment, respectively. Low nitrogen input changed the seasonal dynamics of N2O emission fluxes but had no significant effect on that of CO2 and CH4 emissions. High nitrogen treatment did not affect the seasonal dynamics of greenhouse gas emissions. Soil temperature significantly positively correlated with CO2 and CH4 emission fluxes. There was no correlation between soil temperature and N2O emission flux because the factors affecting N2O emission were complex.

[Fungal Community Structure of Different Degeneration Deyeuxia angustifolia Wetlands in Sanjiang Plain].

To understand the wetland soil fungal community structure and diversity in different degeneration Deyeuxia angustifolia wetlands, the topsoil (0-20) of three different degeneration D. angustifolia wetlands were collected in the Sanjiang Plain field experiment station of the Institute of Nature and Ecology, Heilongjiang Academy of Sciences. The distribution and variation of soil fungal diversity were assessed by high-throughput sequencing method. The results showed that Shannon-Wiener index increased from marsh Deyeuxia angustifolia wetland marsh meadow Deyeuxia angustifolia wetland meadow Deyeuxia angustifolia wetland. Sequence blast showed that the fungal taxonomy belonged to Ascomycota, Basidiomycota, Chytridiomycota, Fungi_unclassified, Zygomycota, which dominant fungi were Fungi_unclassified (75.12%),Ascomycetes (56. 56%), Basidiomycetes (72.65%) in the three degeneration wetlands, respectively. The fungal structure compositions and diversities of marsh meadow Deyeuxia angustifolia wetland and meadow Deyeuxia angustifolia wetland were similar according to Heatmap analysis. The fungal community structure was influenced by soil nutrients (explained 88.62%) and plant composition (explained 9.85%) through the Variation partition analysis (VPA). In conclusion, the fungal community structure was significantly different, which was influenced by soil water content, in different degeneration Deyeuxia angustifolia wetlands in Sanjiang plain. The results may supply scientific basis for studying fungal diversity and spatial heterogeneity in degeneration wetlands.