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Abstract When two or more bacterial species inhabit a shared niche, often, they must compete for limited nutrients. Iron is an essential nutrient that is especially scarce in the marine environment. Bacteria can use the production, release, and re‐uptake of siderophores, small molecule iron chelators, to scavenge iron. Siderophores provide fitness advantages to species that employ them by enhancing iron acquisition, and moreover, by denying iron to competitors incapable of using the siderophore–iron complex. Here, we show that cell‐free culture fluids from the marine bacteriumVibrio fischeriES114 prevent the growth of other vibrio species. Mutagenesis reveals the aerobactin siderophore as the inhibitor. Our analysis reveals a gene, that we nameaerE, encodes the aerobactin exporter, and LuxT is a transcriptional activator of aerobactin production. In co‐culture, under iron‐limiting conditions, aerobactin production allowsV. fischeriES114 to competitively excludeVibrio harveyi, which does not possess aerobactin production and uptake genes. In contrast,V. fischeriES114 mutants incapable of aerobactin production lose in competition withV. harveyi. Introduction ofiutA,encoding the aerobactin receptor, together withfhuCDB, encoding the aerobactin importer are sufficient to convertV. harveyiinto an “aerobactin cheater.” 

Abstract Biofilms, surface‐attached communities of bacterial cells, are a concern in health and in industrial operations because of persistent infections, clogging of flows, and surface fouling. Extracellular matrices provide mechanical protection to biofilm‐dwelling cells as well as protection from chemical insults, including antibiotics. Understanding how biofilm material properties arise from constituent matrix components and how these properties change in different environments is crucial for designing biofilm removal strategies. Here, using rheological characterization and surface analyses ofVibrio choleraebiofilms, it is discovered how extracellular polysaccharides, proteins, and cells function together to define biofilm mechanical and interfacial properties. Using insight gained from our measurements, a facile capillary peeling technology is developed to remove biofilms from surfaces or to transfer intact biofilms from one surface to another. It is shown that the findings are applicable to other biofilm‐forming bacterial species and to multiple surfaces. Thus, the technology and the understanding that have been developed could potentially be employed to characterize and/or treat biofilm‐related infections and industrial biofouling problems.