Antarctic benthic ecological change

The benthic community around Antarctica is diverse and highly endemic. These cold-adapted species are under threat from local and global drivers, including warming, acidification and changes to the cryosphere. In this Review, we summarize observed, experimental and modelled Antarctic benthic ecological change. Warming, glacial melt and retreat, and reduced ice cover are causing regional benthic biomass to increase or decrease, depending on the additional influences of ice scour, turbidity and freshening. Additionally, the dominance of previously cold-restricted or light-restricted taxa is increasing, and several ecological tipping points have already been breached, leading to ecological phase shifts in some habitats. The largest changes have been observed in communities in the shallows of the West Antarctic Peninsula, notably change to distribution, biodiversity, biomass and trophic structure. Models based on observational and experimental evidence indicate that these changes will spread deeper and eastwards throughout this century. Available data are primarily limited to a handful of shallow-water taxa; thus, future work will need to involve multispecies observations and experiments encompassing multiple drivers to understand community and ecosystem responses, and autonomous monitoring techniques to fill geographical, bathymetric, seasonal and taxonomic gaps; advances in environmental DNA and artificial-intelligence-based techniques will help to rapidly analyse such data. The cold-adapted communities on the seafloor around Antarctica are vulnerable to environmental changes. This Review summarizes the regional variations in present and future benthic ecological changes driven by the impacts of climate change and acidification.