Microbial consortia of sulfate-reducing bacteria metabolically coupled to methane-oxidizing archaea have important roles in nature. McGlynn et al. assessed the influence of interspecies spatial arrangements on biosynthetic activity in such consortia from deep-sea sediment incubations, using FISH, NanoSIMS and isotype probing. Interestingly, the biosynthetic activity of entire consortia was unrelated to the degree of mixing between archaeal and bacterial cells, and single-cell activity was independent of proximity to a syntrophic partner. The authors proposed a model for coupling in which electrons are transferred between species and flow freely across assemblies. Consistent with this, the genomes of archaeal consortium members encoded large multi-haem cytochromes, which are capable of electron transfer, and redox-based staining suggested the presence of redox-active haem proteins in the matrix between cells. The authors suggest that interspecies electronic coupling may facilitate the generation of stable syntrophic assemblages.