and physics of sea ice as well as the effects of sea ice retreat on the entire ocean system from the surface to the deep sea. Eleven years ago, Antje Boetius was part of the largest ever sea ice minumum in [...] set off from Tromsø, Norway, towards the North Pole. For two months, a good fifty scientific expedition participants will explore the Arctic in transition as sea ice extent reaches its annual minimum in [...] in the Arctic and its consequences for life in the deep sea. Now she is returning with her team to compare the state of the Arctic today - also with the data from the MOSAiC expedition 2019/20.