Metagenomic insight into taxonomic composition, environmental filtering, and functional redundancy for shaping worldwide modern microbial mats

Abstract

Although microbial mats are considered relictual communities that are nowadays mostly constrained in their distribution by predation and phosphorus availability, they are still found in a wide range of environmental conditions. Their ancestral history, geographical isolation, stratified community composition and interspecies dynamics make them an interesting model to study community ecological processes and concepts. In this study, we analyzed different metagenomic datasets from worldwide modern microbial mats to compare community structure and functions. We found significant differentiation in both alpha and beta diversity of taxonomic and functional categories without significant correlation with temperature and pH. Differences depended more on the presence of very highly abundant cyanobacteria and some generalist microorganisms. Our results suggest that there is more than just Grinnellian niche dynamics in the determination of microbial mat community assembly, opening the hypothesis of interactions as the driver behind these ancient communities. We also discuss the influence of niche dynamics and environmental filtering in the community assembly of microbial mats.