Hydrographic stations sampled during the ASPIRE cruise are projected on the Amundsen Sea Polynya (ASP) bathymetry. Fe addition bioassay experiments were performed at red stations; the water column was sampled at all stations. The dashed line shows the sea ice edge on 1 January 2011; the Getz Ice Shelf (GIS), Dotson Ice Shelf (DIS), and Twaites Ice Tongue are shown in white. Inset shows the location of the ASP in Antarctica.