Multifactorial drivers of antibiotic resistance gene spatial distribution at basin scale: The interplay of selection pressure, host community, and ecological cascades

Antibiotic resistance genes (ARGs), as emerging contaminants, pose significant risks to human and ecological health. However, their basin-scale drivers and mechanisms remain unclear. Using metagenomic sequencing, this study analyzed ARGs in China's Fenhe River Basin. Results revealed a general decrease in ARGs abundance from upstream to downstream, with a notable increase at the Yellow River estuary. ARGs distributions strongly correlated with antibiotic resistant bacteria (ARB), mobile genetic elements (MGEs), and horizontal gene transfer functional genes. ARGs spatial patterns were dually influenced by abiotic and biotic factors. Elevated magnesium (Mg) and molybdenum (Mo) levels increased bacterial and protistan diversity, therebye strengthening competitive and predatory interactions that reduced ARB abundance ( p