The German research vessel Polarstern has charted a previously unrecorded island in the Weddell Sea, adding it to official nautical maps. Scientists from the Alfred‑von‑Kleist‑Institut (AWI) used the Hybrid Antarctic Float Observing System (HAFOS) to track water masses from deep sea to continental shelf. This work dovetails with physical oceanography teams aboard the ship.

Tracking these water masses revealed a sharp decline in Antarctic deep water since 2002, while the outflow from the Larsen Ice Shelf narrows. Prof. Dr. Christian Haas noted that northern Weddell Sea ice thinned to 1.5 m east of the shelf and up to 4 m west, with strong tidal deformation. Melt ponds appeared only sparingly, yet surface melting mirrored Arctic conditions.

New turbulence and biological probes measured sweet meltwater beneath the ice, altering heat exchange and influencing biological colonisation. The data will feed models that quantify the Southern Ocean’s carbon cycle, as researchers plan post‑expedition analyses after the ship docks at the Falkland Islands on 9 April 2026. Polarstern will then head across the Atlantic, returning to Bremerhaven mid‑May.

These observations underscore how Antarctic sea‑ice dynamics drive global currents and sea‑ice melt. By integrating long‑term HAFOS data with real‑time field measurements, the team delivers a more complete picture of ocean‑ice interactions. The updated charts will aid navigation and climate modelling, solidifying Polarstern’s role in polar science.