Soil CH4 and N2O response diminishes during decadal soil warming in a temperate mountain forest

Effects of whole‐soil warming on CH4 and N2O fluxes in an alpine grassland

“…The positive values of N 2 O fluxes in both ambient and warming plots indicated that the alpine grassland soils were a net source of atmosphere N 2 O (Figures 1 and 2). In our study, the whole‐soil warming significantly promoted N 2 O emission (Figures 1 and 2), which was consistent with previous studies (Heinzle et al., 2023; Li et al., 2020; Wang et al., 2021; Zhang et al., 2022). Nonetheless, the N 2 O flux did not respond significantly to experimental warming in the meta‐analysis (Figure 4), while previous studies also showed warming either reduced (Wang et al., 2021; Zhao et al., 2017) or did not change N 2 O flux (Dijkstra et al., 2012; Hu et al., 2010; Zou et al., 2018).…”

“…Heinzle et al. (2023) determined the effects of warming duration on CH 4 and N 2 O fluxes based on a soil warming experiment in a temperate mountain forest. The results showed that the response of both CH 4 and N 2 O fluxes decreased in the sixteenth year of soil warming compared to the second year.…”

“…Given that the net CH 4 flux is determined by both methanogenic and methanotrophic processes, the response of methanogens and methanotrophs to increased temperature is very crucial (Galbally et al., 2008). Heinzle et al., (2023) proposed that methanotrophs were associated with soil $$$ {\mathrm{NH}}_4^{+}\hbox{-} \mathrm{N} $$$ concentrations, and higher soil $$$ {\mathrm{NH}}_4^{+}\hbox{-} \mathrm{N} $$$ due to warming would inhibit the abundance and activity of methanotrophs. However, our study found that whole‐soil warming did not significantly change the measured plant and soil properties (including soil $$$ {\mathrm{NH}}_4^{+}\hbox{-} \mathrm{N} $$$, Table S1), and no significant relationships were found between CH 4 flux and these plant and soil properties (Figure S11).…”

“…CH 4 is taken up by methanotrophic microbes under aerobic conditions and released by methanogens under anaerobic conditions (Dunfield et al., 1993; Lai, 2009), and CH 4 is generally absorbed by soil as a potential carbon sink (Heinzle et al., 2023; Wang et al., 2021). Climate warming could change substrate and nutrient availability as well as gas diffusion, with various effects on CH 4 flux that stimulate uptake (Heinzle et al., 2023), inhibit uptake (Dijkstra et al., 2013), or show no change (Wu et al., 2020). N 2 O can be released through nitrification and denitrification processes.…”

“…As elevated temperature could directly alter microbial metabolism or indirectly change soil microclimate, substrate quantity and quality, gas diffusion, the input of plant litter, and nutrient availability, thus affecting the microbial activity and associated GHGs fluxes (Domeignoz‐Horta et al., 2022; Martins et al., 2017; Xu et al., 2013; Yu et al., 2022). CH 4 is taken up by methanotrophic microbes under aerobic conditions and released by methanogens under anaerobic conditions (Dunfield et al., 1993; Lai, 2009), and CH 4 is generally absorbed by soil as a potential carbon sink (Heinzle et al., 2023; Wang et al., 2021). Climate warming could change substrate and nutrient availability as well as gas diffusion, with various effects on CH 4 flux that stimulate uptake (Heinzle et al., 2023), inhibit uptake (Dijkstra et al., 2013), or show no change (Wu et al., 2020).…”