Abstract:

Methanotrophs, organisms that obtain oxygen by oxidizing methane, are recognized as the only known biological sink for atmospheric CH₄, and forest soil methanotrophs play crucial roles in mitigating global warming. The succession patterns of methanotrophic communities and functions in Wudalianchi volcano forest soils could provide a basis for the study of evolutionary mechanisms between soil microorganisms, the environment, and carbon cycling of temperate forest ecosystems under climate change. In this study, the characteristics and drivers of methanotrophic community structure and function of two volcanic soils at different stages of development are analyzed, including an old volcano and a new volcano, which most recently erupted 300 years and 17 − 19 × 10⁵ years ago, respectively, and a non-volcano hills as control, based on space for time substitution and Miseq sequencing and bioinformation technology. The results showed that CH₄ fluxes were significantly higher in old-stage volcano forest soils than new-stage forest soils and non-volcano forest soils. There were significant differences in the community composition and diversity of soil methanotrophs from different volcano forest soils. Methylococcus was the dominant genus in all soil samples. Additionally, the relative abundance of Methylococcus, along with Clonothrix, Methyloglobulus, Methylomagum, Methylomonas and Methylosarcina, were the important genera responsible for the differences in methanotrophic community structure in different volcano forest soils. The relative abundance of methanotroph belonging to γ-proteobacteria was significantly higher than that belonging to α-proteobacteria (P < 0.05). Chao1, Shannon and Simpson indices of soil methanotrophic community were significantly lower in new-stage volcanos and were significantly affected by bulk density, total porosity, pH, nitrate, dissolved organic carbon and dissolved organic nitrogen. There were significant differences in community structure between new-stage and old-stage volcanoes. Bulk density and pH are important soil properties contributing to the divergence of methanotrophs community structure, and changes in soil properties due to soil development time are important factors driving differences in methanotrophs communities in Wudalianchi volcanic soils.

Key words: Methanotrophs, pmoA, Soil development stage, Volcanoes, Forest soils