This belongs to the set of ice tethered observatory (ITO) from the University of Tromsø. this one is installed on ice. An echosounder is put underwater through a hole in the ice while the topside unit drifts on the ice. The buoy is made to continue drifting even if the ice over which it was installed melts down or breaks appart. It is made thinking about polar bears in the neighborhood.

The acoustic zooplankton and fish profiler, by ASL Environmental  is a multifrequency , scientific echosounder with embedded batteries and data storage capacity. The buoy extracts regularly the data from the instrument and makes it available in the surface. Each buoy has a radio which is used to send the data wireless to another unit in the neighbourhood that can pick it up, for example a ship, an airplane or a drone.