Investigating unexplored ocean currents to the north of Greenland

The 50 scientific participants of the expedition took measurements with the aim of mapping the circulation of Arctic Atlantic water and polar surface water on the shelf and the continental slope north of Greenland. The team also wanted to determine how they connected to the East Greenland Current located further south. At the same time, they studied how circulation and stratification patterns relate to the marine ecosystems by sampling the distributions and connections between nutrients, algae and zooplankton. Another key aspect of the measurement programme was to determine how Atlantic water influences the ocean-driven melting of retreating glaciers, and how the glacial meltwater influences coastal circulation and the export of carbon to the open ocean.

“Our measurement programme was extremely successful. Initial results show that there is a current band at depths of a few hundred metres along the shelf break north and northeast of Greenland. This transports the warm Atlantic water south, out of the Arctic Ocean,” reports the expedition’s chief scientist. There were initial indications that this water had taken different paths through the Arctic Ocean before reaching the northern coast of Greenland. Torsten Kanzow explains further: “When considering currents at the ocean’s surface, which transport cold and fairly fresh polar water masses, the picture was less clear: in the southern section of the survey area, we found distinct currents flowing southwards (so, towards the Fram Strait), as expected. However, interestingly, in the northern section, we observed currents flowing in the opposite direction (so, towards the Nares Strait between Greenland and the Canadian Arctic Archipelago). Subsequent analyses will provide information on what causes this current, and whether it represents part of a current band that transports the polar water masses west from Greenland to the Arctic Ocean. Based on these initial findings, we have been able to install continuous measuring devices, which we will hopefully recover next summer. These will enable us to assess whether the initial insights from this expedition hold true over an entire year.”

The Polarstern's 150th expedition – named EGC-Sources – began on 4 September 2025 in Longyearbyen (Svalbard) and is expected to end on the evening of 24 October 2025 in Bremerhaven. Before this, the German research icebreaker was used on the CONTRASTS expedition in the Central Arctic, led by Dr Marcel Nicolaus, sea ice physicist at the Alfred Wegener Institute – this began on 2 July in Tromsø, Norway, and ended on 1 September in Longyearbyen. This year's Arctic season began with an expedition to the AWI-HAUSGARTEN observatory, led by biologist Dr. Jennifer Dannheim, starting in Bremerhaven on 29 May and ending in Tromsø on 29 June. The Polarstern will now spend around three weeks at the Lloyd Werft shipyard in its home port of Bremerhaven to undergo standard maintenance and repair work, before setting off for Antarctica in mid-November.