Deciphering Centimeter-Scale Microbial Biogeographic Patterns and Community Assembly Processes From A 3D Perspective

Abstract

Background: Revealing the effects of multi-dimensional spatial distribution on microorganisms is crucial for the further understanding of microbial diversity, turnover and ecological processes. However, microbial community assembly and the factors that shape it are still unknown from a three dimensional (3D) perspective. Here, a 3D model was created by performing an exhaustive sampling strategy to a 4x4x4 soil matrix. We examined the dynamics of microbial diversity, biogeographic patterns and microbial assembly processes when transfroming sampling scheme from 2D to 3D.Results: Our results indicated that dispersion of microbial community and significance of distance decay relationship was higher in the 3D compared with 2D sampling scheme, suggesting increased microbial turnover when transforming the model from 2D to 3D. Only a small fraction of community variation can be explained by environmental, spatial factors and spatial canonical axes, possibly due to unmeasured environmental variables. The assembly of microbial community was dominated by deterministic processes that shifted from homogeneous selection to variable selection as we transformed the model from 2D to 3D. The importance of stochasticity increased when homogeneous and variable selection processes were well balanced. However, heterogeneity of existing environmental and spatial variables failed to explain the dynamics of community assembly.Conclusions: Our study revealed significant dynamics of microbial diversity and assembly processes when assessed from 2D and 3D perspectives. As microorganisms are spatially distributed in soil, this spatial dependent diversity and assembly suggests that microbial ecological questions need to be considered in more dimensions than they usually are. Further, new models that integrate all data sets are still needed to disengle the microbial processes in multiple dimensions.

The divergent vertical pattern and assembly of soil bacterial and fungal communities in response to short-term warming in an alpine peatland

“…Soil pH has been reported to be the driving factor for the horizontal structure of the bacterial community (Xia et al, 2016;Liu et al, 2018;Kang et al, 2021). More dimensions must be considered when studying soil microbial communities because of the spatial heterogeneity of the soil and the three-dimensional distribution of microbiomes in soil (Xue R. et al, 2021). However, the vertical responses of soil bacterial and fungal communities to warming remain unclear.…”