Bacterial community and chemical contamination in high-latitude lake waters: a comparative study from the Svalbard and Antarctic Peninsula regions

Microorganisms play a key role in ecosystem functions and maintaining ecological balance, but their communities are sensitive to environmental stressors like climate change, eutrophication, and chemical pollution. This study investigated water samples from Arctic and Antarctic lakes to measure concentrations of persistent organic pollutants (POPs)-including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated naphthalenes (PCNs), chlorobenzenes (CBs)-and trace metals. Simultaneously, bacterial community composition was analyzed using 16S rRNA gene sequencing to explore correlations between contamination and microbial diversity. A comparative approach evaluated different environmental filtering in contaminant profiles and bacterial assemblages between the two poles, representing one of the first studies to combine chemical and microbial data in polar lacustrine ecosystems. Results showed notable differences in taxonomic richness and community composition, with both regions dominated by Proteobacteria and Bacteroidota, though most variation occurred at finer taxonomic levels. Contaminant profiles differed geographically: Antarctic lakes, especially near local human activities, had higher PCBs and PCNs, while Arctic lakes showed more PAHs and CBs, suggesting different contaminant sources or transport pathways. Trace metal distribution in Antarctic lakes varied spatially, influenced by local geology and potentially by biogeochemical effects of penguin populations. Preliminary observations reveal consistent and region-specific correlations between contaminant distribution patterns and bacterial community composition, pointing to potentially significant ecological linkages that merit deeper and systematic investigation. Understanding contaminant-microbe interactions is crucial for assessing ecosystem responses in these vulnerable polar environments.