Science communication, whether internally or to the general public depends on trust, both trust in the source and trust in the medium of communication. With the new 'ecology of communication' this trust is endangered. On the one hand the very term of science communication has been captured by many different actors (e.g., governments, PR experts, universities and research institutions, science journalists, and bloggers) apart from scientists themselves to whom science communication means different things and whose communication is tainted by special interests. Some of these actors are probably more trusted by the general public than others. On the other hand, the channels that are used to communicate science are also not trusted equally. Particularly the widespread use of social media raises doubts about the credibility of the communication spread through them.

For lay people, mass media are the main source of scientific information; that is why science journalists’ selection and depiction of scientific issues is an important field to study. This paper investigates science journalists’ general issue selection and additionally focuses on science journalists’ depiction of nanoscale science and technology and its related scientific evidence (certainty/uncertainty of research findings). Face-to-face interviews with science journalists (n = 21) from different German media channels were conducted. The results show that the professional role conception, personal interest, news factors and organizational processes mainly influence the selection of science journalists. Overall, journalists have increasingly positive attitudes towards nanoscale science and technology. But results indicate that the coverage of scientific evidence differs according to the science journalists’ focus on beneficial or risky aspects of this emerging technology: journalists stress scientific uncertainty predominantly when discussing the risks of nanoscale science and technology.