Emil Ruff is a microbial ecologist at the Marine Biological Laboratory in Woods Hole, Massachusetts. His research focuses on ecosystem functions, community assembly and population dynamics from an interactions-centric perspective. He is particularly interested in microbial mutualisms that lead to novel community functions enabling the partnership to conquer habitats that are unfavorable for each population on its own. Teaming up with other microbes to adapt to challenging conditions is a promising lifestyle in times of rapid global change. To disentangle microbial interactions, Ruff mainly studies ecosystems with reduced complexity, such as natural or laboratory enrichment cultures, microbial blooms or extreme habitats. To obtain insights into each partner’s role, he uses a combination of approaches including batch and continuous cultivation, multi-omics, microscopy, and biogeochemistry. His work has improved our understanding of the sources and sinks of the greenhouse gas methane in seafloor ecosystems and groundwater aquifers. Currently, his lab is involved in projects studying the effect of pollutants on the microbiome of sea anemones, the interactions between sulfur-cycling bacteria and grass roots, and plastics degradation in the deep sea. Ruff earned an M.Sc. in technical biology from the University of Stuttgart and a Ph.D. in microbial ecology from the Max Planck Institute for Marine Microbiology and the University of Bremen, where he stayed for his first postdoc. Before joining the MBL faculty he worked at the University of Calgary department of geoscience funded by an AITF/Eyes High postdoctoral fellowship.