As microorganisms grow and die, they constantly produce and receive a bouquet of chemical signals. Many of these ‘infochemicals’ convey information on the trophic status, cell fate and life history of the producing microorganisms, and are involved in the complex web of microbial interactions in the ocean. Infochemicals can mediate a wide range of biological interactions, such as predator-prey, allelopathy, and host-pathogen interactions. Recent studies have suggested that these micro-scale interactions have profound effects on ecosystem dynamics and global nutrient and carbon cycles.

The recent technical advances in the fields of analytical chemistry, microscale fluid dynamics and cell biology, combined with the wealth of emerging “omics” resources, now provide an unprecedented opportunity to understand the role of chemical signaling in structuring aquatic microbial populations and the possible large-scale impact on the flow of nutrients in the marine environment. This conference builds on the success of the inaugural ‘Marine Microbial Chemical Communication’ conference (‘M2C2-2025’), held at NIOZ, the Netherlands, in March 2025. The meeting brought together an inter-disciplinary group of approximately 100 early-career and established scientists from around the globe to discuss the recent advances and outstanding challenges in the field of marine microbial chemical ecology. The meeting was instrumental in fostering a dedicated scientific community and setting the stage for future collaborative efforts. In its second iteration, the ‘M2C2-2027’ conference will continue to strengthen this growing community by providing a platform for cutting-edge knowledge, discussing emerging technologies, and identifying major bottlenecks in our understanding of the metabolic cross-talk and chemical language that underpin microbial interactions in the marine environment.

By bringing together researchers across disciplines and career stages, this meeting aims to foster new collaborations and advance our understanding of how microbial interactions and chemical communication shape ecological processes across spatial and temporal scales, from microscale exchanges between individual cells to large-scale impacts on marine ecosystem dynamics and global biogeochemical cycles.