The project is one of the Galathea3 expedition's through projects and focuses on interactions between some of the sea's smallest and most numerous organisms, the bacteria. We examine the extent to which marine bacteria are able to combat other bacteria and, in the long term, which chemical drugs they use against each other. This can help to describe why certain groups of bacteria predominate in certain areas of the ocean. In addition, the project has obvious technological "spin-offs", as some of these marine bacterium combat substances may form the basis for new disinfectants, new preservatives, perhaps substances for marine paints – and, at best, perhaps as new antibiotics.