Marine bacterioplankton samples were collected by serial filtration of sea water. Sea water was taken on board of the German research vessel Heincke (cruise: HE361) in July 2011. Collected water samples were prefiltered using glass fiber filters (2.7 µm). Bacterioplankton was subsequently harvested by filtration using a filter sandwich consisting of a glass fiber filter (0.7 µm) and a poly carbonate membrane (0.2 µm). Filters were kept frozen at -80°C.