Microbial Colonization of Plastics in the South Shetland Islands: Insights into Emerging Anthropogenic Niches in Polar Marine Ecosystems

Plastics are increasingly recognized as a novel substrate shaping microbial community structure in marine environments, yet their ecological impact in polar regions remains poorly understood. The South Shetland Islands -characterized by rapid environmental change, expanding human presence, and proximity to Antarctic research stations- represent a critical area for investigating the emergence of plastic-associated microbial assemblages. Funded by the Italian National Antarctic Research Programme (PNRA), the project STORAGE (PNRA22_0000040) aims at investigating the microbial colonization on plastic debris in coastal areas of the South Shetland archipelago, through an experiment involving the deployment of artificial panels at selected sites of Deception and Livingston islands. The studied parameters integrate microbial community composition and function, focusing on total prokaryotic abundance, living and actively metabolizing cell fractions, enzyme activity rates, biofilmproducing cells, microbial community diversity through high‑throughput sequencing and culture methods for the search of antibiotic-resistant bacteria, together with environmental data and chemical characterization. Understanding colonization dynamics is essential, as the formation of a “plastisphere” in the Antarctic could alter local biogeochemical cycles, promote the introduction or dispersal of non-native microorganisms, and provide vectors for microbial exchange between increasingly impacted coastal zones. Given the South Shetland Islands’ role as a gateway for Antarctic marine systems, insights into plastic colonization processes are fundamental for assessing ecological risks and informing conservation and waste‑management strategies in one of Earth’s most vulnerable regions.