The ultimate goal is to identify (clusters of) microbiota able of degrading contaminants in the environment, with emphasis on the marine environment, where it is widespread, concentrations are low but volumes to be treated enormous, and so these self-reproducing cleaners are virtually the only hope for application in practice. Preliminary research revealed that samples from contaminated sites may differ in microbiome composition, or specific taxa can be enriched through exposure. The study requires close cooperation between people sampling at sea, the observed environmentally relevant concentrations, the collection of microbiome samples and their characterisation, and the careful planning of experiments to detect biodegradation potential and the (clusters of) microbiota responsible for that.