Bacterial community assembly in Atlantic cod larvae (Gadus morhua): contributions of ecological processes and metacommunity structure

• Published in: FEMS microbiology ecology Vol. 96; no. 9; p. 1
• Main Authors: Vestrum, Ragnhild I, Attramadal, Kari J K, Vadstein, Olav, Gundersen, Madeleine Stenshorne, Bakke, Ingrid
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.09.2020
• Subjects: Animal health; Animals; Arcobacter; Assembly; Bacteria; Bacteria - genetics; Cod; Colonization; Ecological effects; Ecology; Environmental aspects; Environmental conditions; Fish; Fishes; Gadus morhua; Gastrointestinal Microbiome; Larva; Larvae; Microbiology; Microbiomes; Microbiota; Microbiota (Symbiotic organisms); Microorganisms; Physiological aspects; Stochastic processes; Stochasticity; Norway; microbiota; Atlantic cod; microbial ecology; community assembly; metacommunity; ecological processes
• ISSN: 1574-6941; 0168-6496; 1574-6941
• DOI: 10.1093/femsec/fiaa163

ABSTRACT Many studies demonstrate the importance of the commensal microbiomes to animal health and development. However, the initial community assembly process is poorly understood. It is unclear to what extent the hosts select for their commensal microbiota, whether stochastic processes contribute, and how environmental conditions affect the community assembly. We investigated community assembly in Atlantic cod larvae exposed to distinct microbial metacommunities. We aimed to quantify ecological processes influencing community assembly in cod larvae and to elucidate the complex relationship between the bacteria of the environment and the fish. Selection within the fish was the major determinant for community assembly, but drift resulted in inter-individual variation. The environmental bacterial communities were highly dissimilar from those associated with the fish. Still, differences in the environmental bacterial communities strongly influenced the fish communities. The most striking difference was an excessive dominance of a single OTU (Arcobacter) for larvae reared in two of the three systems. These larvae were exposed to environments with higher fractions of opportunistic bacteria, and we hypothesise that detrimental host–microbe interactions might have made the fish susceptible to Arcobacter colonisation. Despite strong selection within the host, this points to a possibility to steer the metacommunity towards mutualistic host–microbe interactions and improved fish health and survival. Bacterial community assembly in Atlantic cod larvae is driven by deterministic and stochastic processes and influenced by the bacterial metacommunity structure.