The effectiveness of static versus dynamic learning material was tested using fish biodiversity as learning domain. Eighteen fish species were presented either as videos or selected freeze-frames to students. Thereafter, students exercised identifying these species in their natural habitats during snorkeling. Students' knowledge of biodiversity was measured from test videos before (posttest 1) and after (posttest 2) snorkeling as the number of recognized species. Results showed significant knowledge gains between posttest 1 and 2. For the presentation format (static vs. dynamic) there was no significant main effect. However, a significant interaction showed that the students' knowledge improved from posttest 1 to 2 to a larger extent in the dynamic group. The study was conducted within a university curriculum for which a mobile learning scenario using portable DVD-players was applied for the first time. Overall results indicate a high potential for using mobile devices in informal settings during field trips.