Extracellular vesicles — new players in cell–cell communication in aquatic environments

•EVs are produced by cells from all domains of life.•EVs can contain diverse cargo such as nucleic acids, enzymes and small molecules.•EVs impact host–virus interactions, quorum sensing and gene transfer.•Recent studies highlight EVs function in marine ecosystems.•EV mediated microbial communication in aquatic environments may have major ecological implications. Communication between microorganisms in aquatic environments can influence ecosystem function and determine the structure and composition of microbial populations. This microbial cross talk can be mediated by excretion of specialized metabolites or extracellular vesicles (EVs). Recently it has become apparent that cells across all domains of life produce EVs that may convey specific targeted signals that can modulate cell fate, morphology and susceptibility to viruses. The vast majority of knowledge about EVs is derived from studies of mammalian tissues, parasitic host–pathogen interactions and model bacterial systems. Very little is known about the role of EVs in aquatic environments, although they have potential to influence community structure and trophic-level interactions. We propose functions and ecological implications of communication via EVs in aquatic microbial ecosystems.