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Ziegler AF, Smith CR, Edwards KF, Vernet M
Glacial dropstones: islands enhancing seafloor species richness of benthic megafauna in West Antarctic Peninsula fjords
While soft-sediment megafaunal communities along the West Antarctic Peninsula fjords are deemed to be “biodiversity hotspots”, the contribution of hard-substrate fauna remained unexplored. Here, Ziegler and colleagues show that the inclusion of glacial dropstones enhanced species richness at 400-700 m depths on the West Antarctic Peninsula by 20%. Dropstones increased heterogeneity and their communities adhered to principles of Island Biogeography Theory, supporting their function as island habitats. A combination of island-like assembly processes and abiotic environment factors appear to shape these benthic communities, along with dispersal and recruitment-limitation. Dropstones were utilized by both sessile and mobile megafauna, many of which may be negatively impacted as climate warming increases sedimentation rates and dropstone burial.