Stochastic Assembly Leads to Alternative Communities with Distinct Functions in a Bioreactor Microbial Community

Abstract

The processes and mechanisms of community assembly and its relationships to community functioning are central issues in ecology. Both deterministic and stochastic factors play important roles in shaping community composition and structure, but the connection between community assembly and ecosystem functioning remains elusive, especially in microbial communities. Here, we used microbial electrolysis cell reactors as a model system to examine the roles of stochastic assembly in determining microbial community structure and functions. Under identical environmental conditions with the same source community, ecological drift (i.e., initial stochastic colonization) and subsequent biotic interactions created dramatically different communities with little overlap among 14 identical reactors, indicating that stochastic assembly played dominant roles in determining microbial community structure. Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors. Most importantly, the newly formed communities differed substantially in community functions (e.g., H2 production), which showed strong linkages to community structure. This study is the first to demonstrate that stochastic assembly plays a dominant role in determining not only community structure but also ecosystem functions. Elucidating the links among community assembly, biodiversity, and ecosystem functioning is critical to understanding ecosystem functioning, biodiversity preservation, and ecosystem management.

New Steady-State Microbial Community Compositions and Process Performances in Biogas Reactors Induced by Temperature Disturbances

“…The replicate biogas reactors also had similar microbial community compositions based on RDP classification, PCoA, and hierarchical cluster analysis. However, Zhou et al found that, under the same environmental conditions, both bacterial community compositions and functions in replicate microbial electrolysis cells were different, and they proposed that stochastic assembly played a dominant role in determining not only community structure but also ecosystem functions [35]. Based on our results, the microbial community compositions and functions in anaerobic digestion of cattle manure were not obviously affected by stochastic assembly.…”

Effects of dispersal and selection on stochastic assembly in microbial communities

“…Because microbes have high dispersal rates, large population sizes, fast growth rates and a propensity for dormancy, communities were traditionally thought to assemble deterministically. However, recent characterizations of microbial communities provide evidence that in addition to environmental selection, stochastic processes can be important drivers of microbial community assembly (Ferrenberg et al, 2013;Nemergut et al, 2013;Zhou et al, 2013;Fukami, 2015).…”

Microbial community structure and function of Nitrobenzene reduction biocathode in response to carbon source switchover

“…Moreover, the clear microbial communities succession from the initial NB-reducing inoculum to the NB-reducing biocathode biofilms, and microbial functional gene diversity, especially putative functional genes related to electrons transfer that in response to carbon source switchover (from organic glucose to inorganic bicarbonate) using high-throughput metagenomics technology have not yet been understood. Illumina MiSeq sequencing platform (Caporaso et al, 2012) and GeoChip-based functional gene arrays Liu et al, 2010;Zhang et al, 2013;Zhou et al, 2013) are suitable tools to characterize microbial community structure, function and metabolic potential in NBreducing biocathode biofilms.…”