Publicly available bathymetry and geophysical data has been used to map geomorphic features of the Antarctic continental margin and adjoining ocean basins at scales of 1:1-2 million. The key bathymetry datasets used were GEBCO08 and ETOPO2 satellite bathymetry (Smith & Sandwell 1997), in addition to seismic lines in key areas. Twenty-seven geomorphic units were identified based on interpretation of the seafloor bathymetry with polygons digitised by hand in ArcGIS.

Publicly available bathymetry and geophysical data has been used to map geomorphic features of the Antarctic continental margin and adjoining ocean basins at scales of 1:1-2 million. The key bathymetry datasets used were GEBCO08 and ETOPO2 satellite bathymetry (Smith & Sandwell 1997), in addition to seismic lines in key areas. Twenty-seven geomorphic units were identified based on interpretation of the seafloor bathymetry with polygons digitised by hand in ArcGIS.

Our knowledge of life at the Antarctic sea-bed has increased in the past decades with increasing ship-based surveys and monitoring sites, new technologies and data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that limits our ability to assess the state of the Southern Ocean benthos on larger scales. The seafloor communities that inhabit the Antarctic shelf are often diversity hotspots. These habitats are important in the generation of ‘blue carbon’ and habitat for commercial fish species, for this reason we focus on these habitats. Many Southern Ocean seafloor habitats and their communities seem to be especially vulnerable to certain drivers of change including increasing ocean temperatures, iceberg scour, sea-ice melt, ocean acidification, fishing pressures, pollution and non-indigenous species. Some of the most vulnerable areas include those experiencing rapid regional warming and increased iceberg-scouring e.g. the West Antarctic Peninsula; where human activities and environmental conditions increase the potential for the establishment of non-indigenous species e.g. sub-Antarctic islands and tourist destinations and areas with fishing activities e.g. around South Georgia, Heard and MacDonald Islands. Vulnerable species include calcifying species susceptible to increasing ocean acidity as well as slow-growing habitat forming species that can be damaged by fishing gears e.g. sponges, bryozoan and coral species. Management regimes can protect seafloor habitats and key species from fishing activities but only if they consider specific traits, such as longevity, food availability, their physiological adaptation and rare or common occurrences. Ecosystem-based management practices and long-term protected areas may be the most effective in the preservation of vulnerable seafloor habitats. However, action is needed to reduce carbon emissions to limit the impact of increasing ocean temperatures and ocean acidification. We focus on outlining seafloor responses to drivers of change observed to date and projections for the future. We discuss the need for action to preserve seafloor habitats under climate change and fishing pressures. <b>Citation:</b> Brasier MJ, Barnes D, Bax N, Brandt A, Christianson AB, Constable AJ, Downey R, Figuerola B, Griffiths H, Gutt J, Lockhart S, Morley SA, Post AL, Van de Putte A, Saeedi H, Stark JS, Sumner M and Waller CL (2021) Responses of Southern Ocean Seafloor Habitats and Communities to Global and Local Drivers of Change. <i>Front. Mar. Sci.</i> 8:622721. doi: 10.3389/fmars.2021.622721

Publicly available bathymetry and geophysical data has been used to map geomorphic features of the Antarctic continental margin and adjoining ocean basins at scales of 1:1-2 million. The key bathymetry datasets used were GEBCO08 and ETOPO2 satellite bathymetry (Smith & Sandwell 1997), in addition to seismic lines in key areas. Twenty-seven geomorphic units were identified based on interpretation of the seafloor bathymetry with polygons digitised by hand in ArcGIS.

The East Antarctic slope on the Sabrina margin has been shaped by diverse processes related to repeated glaciation. Differences in slope along this margin have driven variations in sedimentation that explain the gully morphology. Areas of lower slope angles have led to rapid sediment deposition during glacial expansion to the shelf edge, and subsequent sediment failure. Gullies in these areas are typically extremely U-shaped, initiate well below the shelf break, are relatively straight and long, and have low incision depths. Areas of higher slope angles enhance the flow of erosive turbidity currents during glaciations associated with the release of sediment-laden basal meltwaters. The meltwater flows create gullies that typically initiate at or near the shelf break, are V-shaped in profiles, have high sinuosity, deep incision depths and a relatively short down slope extent. The short down slope extent reflects a reduced sediment load associated with increased seawater entrainment as the slope becomes more concave in profile. These differences in gully morphology have important habitat implications, associated with differences in the structure and beta-diversity of the seafloor communities. This upper slope region also supports seafloor communities that are distinct from those on the adjacent shelf, highlighting the uniqueness of this environment for biodiversity. <b>Citation:</b> A.L. Post, P.E. O'Brien, S. Edwards, A.G. Carroll, K. Malakoff, L.K. Armand, Upper slope processes and seafloor ecosystems on the Sabrina continental slope, East Antarctica, <i>Marine Geology</i>, Volume 422, 2020, 106091, ISSN 0025-3227, https://doi.org/10.1016/j.margeo.2019.106091.