Spatial distribution of airborne antibiotic resistance genes over the Pacific ocean: ocean-atmosphere transfer

Abstract

Antibiotic resistance genes (ARGs) are increasingly recognized as global determinants within the ‘One Health’ framework; however, the diversity of ARGs and their transmission mechanisms across the ocean-atmosphere interface remain poorly understood. In this study, we simultaneously quantified airborne and seawater-derived ARGs along a 3868 km transect covering Korean coastal waters, the North Pacific Ocean, and the Bering Sea. The normalized relative abundance of ARGs (copies/16S rRNA gene) varied across 10 targeted ARG subtypes, with average values of 1.1 × 10−4 ± 5.5 × 10−4 copies/16S rRNA gene in aerosol and 1.7 × 10−4 ± 1.1 × 10−3 copies/16S rRNA gene in seawater. The blaTEM and tetBP genes were dominant subtypes in both matrices, reflecting their roles as core components of the marine resistome. Furthermore, specific genes, including tetA, tetZ, ermB, qnrD, and oqxA, showed proportional enrichment in aerosols, indicating matrix-specific distribution patterns. Exploratory partial canonical correspondence analysis (pCCA) revealed that air mass origin (oceanic vs. terrestrial) and meteorological variables (e.g., air temperature, solar radiation, wind speed, and atmospheric pressure) significantly influence the spatial distribution of airborne ARGs. In addition, Polaribacter sp. and Sediminibacterium sp. were identified as putative microbial hosts potentially facilitating the mobilization of airborne ARGs across the ocean. Strong correlations between intI1 and certain ARGs (e.g., oqxA, ermB, and blaTEM) further suggest the potential role of horizontal gene transfer in resistance dissemination. Our findings provide a critical baseline indicating that airborne ARGs are widely disseminated in remote marine environments, emphasizing the need for global monitoring of the atmospheric resistome