Penguin guano shapes Antarctic environmental microbiomes: insights from DNA metabarcoding

Introduction: Antarctic soils are characterized by extreme environmental conditions, including low temperatures, limited liquid water, and a scarcity of organic nutrients, fostering unique bacterial communities vital for biogeochemical cycling and ecosystem functioning. This study investigates the influence of penguin guano on microbial diversity in ornithogenic environments compared to non-ornithogenic environments on King George Island, Antarctica. Material and methods: We sampled lake sediments receiving continuous penguin guano input, soil from an Adélie penguin rookery, and soil without penguin influence. The microbial communities within these samples were then analyzed using high-throughput sequencing of the 16S rRNA gene. Results: Sequencing revealed that ornithogenic soils exhibited higher microbial diversity and distinct community compositions. Notably, Actinobacteria, Proteobacteria, and Bacteroidota were simultaneously prevalent in guano-influenced environments, while the detection of predatory Myxococcota suggests complex trophic interactions in rookery soils. In contrast, Actinobacteria was dominant in non-ornithogenic soils. Uniquely, two bacterial phyla, Planctomycetota and Sumerlaeota, were identified for the first time in Antarctica microhabitats, highlighting its unexplored microbial diversity. Conclusions: Our findings provide comparative baseline insights into the critical role of penguin activity in shaping microbial communities in extreme ecosystems and underscore the need for further research into the functional roles of these communities in the context of ongoing environmental changes in Antarctica.