【About Video】 CTD (Conductivity-Temperature-Depth) observations are fundamental to investigating the structure of the ocean. It measures the vertical profiles of salinity and temperature. Water sampling bottles are attached to a CTD- Rosette-system. In August 2019, we used the CTD- Rosette-system in the Funka Bay, Hokkaido, Japan, by a training ship Ushio-Maru (Hokkaido University). Listen to the sound when the lid of sampling bottle closes.