Microbial diversity and interaction networks in polar Sediments: Insights from the Circum-Antarctic, Antarctic...

The unique environmental characteristics of polar regions highlighted the essential role of microorganisms in these environments. We analyzed microbial community composition in surface sediments from the Antarctic Peninsula (AP) and Circum-Antarctic (CA), and conducted a meta-analysis incorporating published microbial community data from AP, CA and the Arctic to explore differences in microbial composition, interactions, and community assembly processes. The results suggest that the relatively stable and homogeneous environmental conditions in the CA region may contribute to maintaining higher microbial diversity. In terms of community composition, AP was particularly enriched in sulfur-reducing bacteria, such as Sva1033 and Sva0485. Microbial co-occurrence network analysis revealed that CA exhibited the highest network complexity, followed by AP, with the Arctic showing the lowest complexity. Further robustness analysis demonstrated that CA had the lowest network stability. Both deterministic and stochastic processes jointly shaped the geographic distribution patterns of microorganisms across the three regions, with AP predominantly influenced by heterogeneous selection, CA by undominated processes, and the Arctic by dispersal limitation. This study provides important insights into the diversity and assembly processes of microbial communities in polar marine surface sediments.