Application of the microbial community coalescence concept to riverine networks

Abstract

Flows of water, soil, litter, and anthropogenic materials in and around rivers lead to the mixing of their resident microbial communities and subsequently to a resultant community distinct from its precursors. Consideration of these events through a new conceptual lens, namely, community coalescence, could provide a means of integrating physical, environmental, and ecological mechanisms to predict microbial community assembly patterns better in these habitats. Here, we review field studies of microbial communities in riverine habitats where environmental mixing regularly occurs, interpret some of these studies within the community coalescence framework and posit novel hypotheses and insights that may be gained in riverine microbial ecology through the application of this concept. Particularly in the face of a changing climate and rivers under increasing anthropogenic pressures, knowledge about the factors governing microbial community assembly is essential to forecast and/or respond to changes in ecosystem function. Additionally, there is the potential for microbial ecology studies in rivers to become a driver of theory development: riverine systems are ideal for coalescence studies because regular and predictable environmental mixing occurs. Data appropriate for testing community coalescence theory could be collected with minimal alteration to existing study designs.

Community Assembly Mechanisms Underlying the Core and Random Bacterioplankton and Microeukaryotes in a River–Reservoir System

“…Furthermore, in highly dynamic habitats, such as riverine ecosystems, dramatic environmental variations and strong dispersal effects occur. As such, it may be difficult to distinguish the pure effects of selection and dispersal, and planktonic populations are highly influenced by the coalescence of taxa from adjacent terrestrial or aquatic ecosystems [54]. Needless to say, purely neutral ecological processes and the local niche-based evolution of regional neutrality cannot be separated by partitioning beta diversity without looking at trait variation [55].…”

Community coalescence: an eco-evolutionary perspective

“…wind, tides or river flow) and biotic (e.g. animal courtship, parent-offspring interactions or leaves falling) factors [2][3][4][5][6]. Moreover, coalescence occurs owing to human activities such as industrial anaerobic digestion [7], agriculture [8,9] and between-human contact [10,11] (e.g.…”

Rare Microbial Taxa Emerge When Communities Collide: Freshwater and Marine Microbiome Responses to Experimental Seawater Intrusion

“…Microbial community coalescence occurs every time a leaf falls to the ground, a soil particle is blown into a new landscape, or two bodies of water mix. Despite the ubiquity of microbial community coalescence, the formal recognition of this concept is fairly recent in microbial ecology (Rillig et al 2017; Mansour et al 2018). In fact, Mansour et al (2018) suggest that many experimental studies with microbial communities are unacknowledged community coalescence experiments.…”