Upper slope processes and seafloor ecosystems on the Sabrina continental slope, East Antarctica

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.