SFB754 Zooplankton and particle distribution from UVP5 measurements

To expand the ecological knowledge on fragile organisms (such as giant rhizaria, medusae, ctenophores, and siphonophores) in situ imaging techniques were employed in addition to net sampling. An Underwater Vision Profiler 5 (UVP5; Picheral et al., 2010) was routinely mounted on the CTD/rosette during most SFB 754 cruises since 2012. During the cruises in 2012 and 2013 a UVP5 was used that was kindly provided by the Laboratoire d'Océangraphie de Villefranche-sur-Mer. The instrument consists of one down facing HD camera in a steel pressure case and two red LED lights which illuminate a 0.88 to 0.93 l volume (depending on the actual set-up). During the downcast, the UVP5 takes 3-20 pictures of the illuminated field per second. For each picture, the particles are counted and sized immediately and the data is stored in the instrument for later analysis