The Weddell Sea and the ocean off Dronning Maud Land, constituting the Weddell Gyre, are representative of the high-latitude Southern Ocean due to its pronounced seasonality, circumpolar currents, deep-water formation and seasonal sea-ice cover. The Weddell Gyre connects water masses from the Antarctic Circumpolar Current with those shaped by the large ice shelves and sea-ice formation in the southern perimeter of the Weddell Gyre. Biological and biogeochemical processes are strongly influenced by these conditions and contribute to a unique Weddell Sea ecosystem.

A portion of the western Weddell Sea is already experiencing consequences of climate change, including the acceleration of mass loss from ice shelves, enhanced ocean warming and freshening, rising air temperatures, and changes in wind patterns. This likely has an emerging influence on the local biological and biogeochemical processes. The eastern part of the Weddell Gyre, off Dronning Maud Land, however, appears relatively stable but is expected to experience warming, sea-ice retreat and ice-shelf loss in the course of this century. The re-emergence of the Maud Rise Polynya, with a potentially significant impact on regional water masses and biogeochemistry, underscores the importance of observing and understanding this region. Establishing knowledge of the present biological and biogeochemical processes and coupling with physics prior to major changes in this region is essential.

This special issue emerged from an October 2020 workshop organized by the Southern Ocean Observing System (SOOS) Weddell Sea and Dronning Maud Land Regional Working Group that brought together numerous scientists across multiple disciplines. However, the issue is open to anyone and we welcome additional contributions.