In May 2011 we deployed nine 25 m long KOSMOS units for 5 weeks in a Norwegian fjord (Raunefjord, 60.265°N, 5.205°E) close to the city of Bergen, in order to study the influence of ocean acidification on the succession of a plankton community under in-situ conditions. Towards the end of the study (7th of June), we mounted an underwater camera on a diving torch and slowly lowered this setup to a depth of approximately 24.5 m. A variety of different organisms (copepods, fish larvae, jelly fish, appendicularians) and detrital aggregates can be seen during the descent of the camera into the deep. The conical mesocosm sediment trap and particles collected in the funnel can be seen at the end of the video in 25 m water depth. The video shows that we enclosed and studied lively plankton communities within the KOSMOS system. "The video can be downloaded on OceanRep but is also available on the KOSMOS channel of the streaming platform YouTube."