Characteristics of bacterial communities in aquatic ecosystems near the Collins glacial (Fildes Peninsula, Antarctica)

Abstract

Bacteria are vital for maintaining ecosystem function in the rapidly changing environment, but limited data was reported regarding the characteristics of bacterial communities along the regional-scale in aquatic ecosystems on the Fildes Peninsula (Antarctica), where vulnerable aquatic habitats have been affected by the dramatic retreat of the Collins glacier. This study revealed differences and hidden connections of bacterial communities in two aquatic ecosystems (periglacial lakes and coves) near Collins glacier using amplicon sequencing. The results showed periglacial lakes and coves harbored 568 and 388 unique OTUs, respectively, but also shared 199 common OTUs, which meant there existed some linkages connections between the two ecosystems. Compared to periglacial lakes, communities in coves exhibited decreased richness and Shannon index (P < 0.05) and were dominated by Proteobacteria, Cyanobacteria, and Bacteroidota, while periglacial lakes were dominated by Bacteroidota, Actinobacteria, and Proteobacteria. Periglacial lakes and coves harbored significantly distinct bacterial communities, while their β-diversity were both dominated by turnover. Indicator species identified in coves, such as Polaribacter and Sulfitobacter, were predicted more involved in S cycle. FAPROTAX and PICRUSt2 analysis revealed significantly higher metabolic potential for N and S cycles in the coves. pH was a common environmental factor influencing community variation in both habitats. As indicated by network analysis, the periglacial lake network exhibited greater complexity and stability, with higher robustness value and smaller shifts in natural connectivity. It could be concluded that there were some linkages and similar influencing factors in the two aquatic ecosystems, but that there were significant differences in bacterial community diversity and co-occurrence networks, as influenced by habitat differentiation. These results further deepen our understanding of bacterial community characteristics in the two typical aquatic habitats near the Collins glacier, providing new insights into the impact of glacier retreat on downstream ecosystems.

Keywords

• Bacterial communities
• Diversity
• Network complexity and stability
• Aquatic ecosystem
• Fildes Peninsula