Responses of Southern Ocean Seafloor Habitats and Communities to Global and Local Drivers of Change

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. Citation: 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. Front. Mar. Sci. 8:622721. doi: 10.3389/fmars.2021.622721