Anthropogenic PAHs reshape sedimentary microbiomes and ecotoxicological risks in polar regions: A...

The analysis of the composition and functional gene responses of sedimentary microbial communities to polycyclic aromatic hydrocarbons (PAHs) is essential for evaluating the pollution status of PAHs in polar regions. PAH concentrations and microbiome characteristics are quantified using advanced instrumental detection combined with metagenomic analysis. Overall, PAHs exhibit relatively high levels of contamination in polar regions, whereas variations in the abundance of functional genes indicate potential degradation propensities among different sedimentary microbial communities. The PAHs in the study area are primarily attributed to fossil fuel combustion, with local anthropogenic emissions considered the main drivers of contaminant accumulation. Sedimentary bacterial communities and their functions are significantly influenced by PAH contamination. Correlation analysis identifies 4H-Naphthalene, Naphthalene, 1-Indanone, Anthracene, Benzo[c]phenanthrene and 1,4-Naphthoquinone as the most critical compounds affecting microbial communities. The co-occurrence of PAH degradation genes with nitrogen- and sulfur-cycling genes in several MAGs suggests that PAH biodegradation may be enhanced through the utilization of nitrate and sulfate as electron acceptors. Within a pan-Arctic and Antarctic framework, the responses of sedimentary microbiomes to PAH contamination are examined, providing novel insights into the comprehensive evaluation of PAH pollution levels and associated ecological risks in polar regions.