Scientists at University of Leeds are using a robotic submarine to study a deep channel that runs along the floor of the Black Sea. The underwater river is denser than the surrounding water and composed of sediment with a high salinity. There are similarities to land-based rivers but also major differences in how the mass flows. Study of the flow is being performed by a 7-metre torpedo-shaped robot called the Autosub3 because its accurate positioning system allows it to be programmed to stay just above the channel to prevent damage.