Fig. 1: Map over the study area and temperature sections.

Temperature sections a west and b east of the Filchner Trough (purple/green line in c, respectively). The divergent colormap highlights the depth of the thermocline, with Winter Water above (in blue) and (modified) Warm Deep Water below (in red). c Map over the study area with bathymetry²⁷ in blue shading according to the color bar and the 500 m isobath highlighted in black. The circulation in the area is shown with blue (outflow of Ice Shelf Water) and red (the Antarctic Slope Current and the Antarctic Coastal Current) arrows^34,35. Dashed arrows indicate seasonal flow^35,36. Floating ice shelves are shown in dark gray and land in light gray. The location of Conductivity-Temperature-Depth (CTD) stations on the continental slope is marked with white dots. FT indicates the Filchner Trough, and FIS is the Filchner Ice Shelf. d Mean current from moorings listed in Table 1. Currents observed within the dense plume are shown in blue, and currents observed above/outside the plume are shown in red. The black arrow on the shelf gives the velocity scale. Note that there is a factor three difference between the blue and red scales. Isobaths are shown every 250 m with the 500 m isobath in bold, and the area is marked with a red rectangle in d. e A map showing the location of the study area in the southwestern Weddell Sea (red square).