Microorganisms are key players in terrestrial and aquatic ecosystems, controlling all major biogeochemical fluxes of elements. Although the study of microbial ecology goes back several decades, our ability to understand or predict the taxonomic and functional responses of microbial communities to changes in environmental conditions remains limited. One of the reasons may be that microbial communities may contain species that are not adapted to the local environment and do not contribute to community function-ing, given that microorganisms can be dispersed long distances and can persist inactive out of their suitable habitats for long periods. The advent of sequencing technologies, which enabled an improved access to microbial diversity and expanded the scale of stud-ies, revealed that microbes often form part of larger metacommunities in which local as-semblages are linked by the dispersal of species. However, disciplines such as microbial limnology and oceanography (the study of freshwater and marine microorganisms, re-spectively) often operate in isolation, providing a fragmented view of a naturally connect-ed microbial world. This review seeks to summarize what we have learnt over the past few years regarding the effect of microbial dispersal and connectivity on the structuring and functioning of aquatic microbial communities, with particular emphasis on bacterio-plankton assemblages. These investigations have highlighted that terrestrial, freshwater and marine microbiomes are intimately linked by the transport of taxa through flowing water, the air, or processes such as marine particle sinking, and hence that understanding the drivers and ecological consequences of microbial ecology and biogeography requires going beyond ecosystem boundaries. Sharing knowledge and expertise between tradition-ally independent disciplines will be essential to advance towards a more holistic view of microbial ecology that considers species linkages between different ecosystems

Conferencia sobre el trabajo premiado en 2020 por la Secció de Ciències Biològiques Pius Font i Quer de Ciències de la Vida del Intitut d'Estudis Catalans (IEC)

Peer reviewed