© Esther Horvath
30. October 2023
The chang­ing Arctic Ocean

Antje Boetius on a research expedi­tion in the Arctic

On Septem­ber 30, 2023, the research vessel Polarstern returned to Bremer­haven. Hector Fellow Antje Boetius, Direc­tor of the Alfred Wegener Insti­tute, Helmholtz Centre for Polar and Marine Research (AWI), partic­i­pated in the Polarstern expedi­tion named ArcWatch‑1, which started on August 3 in Tromsø, Norway. The team of almost 100 crew and scien­tists measured sea ice thick­ness and proper­ties, recorded the currents and chemi­cal proper­ties of the ocean and inves­ti­gated life in and under the ice, in the open water and at the bottom of the deep sea. Their data show signif­i­cant changes compared to previ­ous expeditions.

The large-scale deploy­ment of the EM-Bird, a sensor system deployed from the Polarstern helicopter, as well as paral­lel aircraft campaigns showed: the thick­ness of the level sea ice was still 1.2 metres at the begin­ning of Septem­ber — more than in the summer of the MOSAiC expedi­tion in 2020 or at the largest sea ice minimum in 2012. “Accord­ingly, we found hardly any ice algae on the under­side of the sea ice. Especially Melosira arctica was missing, which can form metre-long chains and is an impor­tant nutri­ent supplier for the entire ecosys­tem. The ice looked rather dead this year. Due to the darken­ing by snow, algae floated up from the water and formed a film under the ice, to get some light,” reports chief scien­tist Antje Boetius. The physi­cal oceanog­ra­phers on board also discov­ered changes in the upper­most ocean layer, which was saltier than in previ­ous years. The compar­i­son with the previ­ous survey years 2012 and 2020 also showed differ­ences for the plank­tonic life float­ing in the water.

The scien­tists of the research expedi­tion "AWIs4Future", a regional group of Scien­tists for Future, took the oppor­tu­nity to appeal on social media to take the climate crisis seriously with an image from the Arctic and called for partic­i­pa­tion in the global climate strike.

Inter­ested parties can get further insights into the expedi­tion as early as the turn of the year: A documen­tary, produced by UFA Documen­tary, with the working title ARCWATCH — HOFFNUNG IM EIS will be broad­cas on Decem­ber 29 at 9:45 p.m. on the German TV channel ARD and will be avail­able in the ARD-Mediathek.