Methanotrophic bacteria are crucial in the regulation of methane concentration in the atmosphere and therefore for regulating our climate. Despite all research efforts there is still little understanding of the role of biological interaction on the functioning of methane oxidizers. In the VolMob project we investigate the interactions between methanotrophs and other bacteria mediated by volatile compounds. Initial experiments have demonstrated positive as well as negative effects of volatiles produced by heterotrophic bacteria. The coming years we will focus on unravelling the mechanisms behind these effects.