Supplementary Figures and Methods from The ecology of heterogeneity: soil bacterial communities and C dynamics

Heterogeneity is a fundamental property of soil that is often overlooked in microbial ecology. Although it is generally accepted that the heterogeneity of soil underpins the emergence and maintenance of microbial diversity (Treves DS et al. 2003 Microb. Ecol. 45, 20–28. (doi:10.1007/s00248-002-1044-x)), the profound and far-reaching consequences that heterogeneity can have on many aspects of microbial ecology and activity have yet to be fully apprehended and have not been fully integrated into our understanding of microbial functioning. In the following, we will first argue that the heterogeneity of the soil microbial environment, and the consequent uncertainty associated with acquiring resources, affect how microbial metabolism, motility and interactions have evolved and, ultimately, affect the overall microbial activity that is represented in ecosystem models, such as heterotrophic decomposition or respiration. We will then present an analysis of predicted metabolic pathways for soil bacteria, downloaded from the MetaCyc pathway/genome database collection (https://metacyc.org/). The analysis suggests that while there is a relationship between phylogenic affiliation and the catabolic range of soil bacterial taxa, there does not appear to be a trade-off between the 16S rRNA gene copy number, taken as a proxy of potential growth rate, of bacterial strains and the range of substrates that can be used. Finally, we will present a simple, spatially explicit model that can be used to understand how the interactions between decomposers and environmental heterogeneity affect the bacterial decomposition of organic matter.This article is part of the theme issue ‘Conceptual challenges in microbial community ecology’.