The “Ice Station POLarstern” (ISPOL) drift experiment was an interdisciplinary study within the perennial sea ice of the western Weddell Sea that brought together scientists from 11 countries. The primary goal was the monitoring of physical and biogeochemical interactions between atmosphere, ice and ocean at the transition from austral winter to summer. Special emphasis was set on the processes controlling sea-ice melting and the onset of phytoplankton bloom. The ISPOL observations complement the study of the seasonal sea ice–ocean cycle in the western Weddell Sea, initiated by the summer to winter drift of Ice Station Weddell-1 (ISW-1) in 1992. This volume contains a collection of papers that range from the atmosphere to the deep ocean, from micro- to macro-scales, from physics to biology with their interactions investigated during the 36 days of the ISPOL experiment.