资源环境科技发展态势分析平台

Antarctica has long been considered biologically isolated'. Global warming will make parts of Antarctica more habitable for invasive taxa, yet presumed barriers to dispersal-especially the Southern Ocean's strong, circumpolar winds, ocean currents and fronts-have been thought to protect the region from non-anthropogenic colonizations from the north(1,2). We combine molecular and oceanographic tools to directly test for biological dispersal across the Southern Ocean. Genomic analyses reveal that rafting keystone kelps recently travelled >20,000 km and crossed several ocean-front 'barriers' to reach Antarctica from mid-latitude source populations. High-resolution ocean circulation models, incorporating both mesoscale eddies and wave-driven Stokes drift, indicate that such Antarctic incursions are remarkably frequent and rapid. Our results demonstrate that storm-forced surface waves and ocean eddies can dramatically enhance oceanographic connectivity for drift particles in surface layers, and show that Antarctica is not biologically isolated. We infer that Antarctica's long-standing ecological differences have been the result of environmental extremes that have precluded the establishment of temperate-adapted taxa, but that such taxa nonetheless frequently disperse to the region. Global warming thus has the potential to allow the establishment of diverse new species-including keystone kelps that would drastically alter ecosystem dynamics-even without anthropogenic introductions.