Antibiotic-induced alterations of biogeochemical processes of nitrogen mediated by microorganisms in hyporheic zone and their environmental implications: A systematic review

Abstract

Antibiotics persist as critical pervasive pollutants within hyporheic zones, exerting selective pressures that disrupt the essential nitrogen (N) cycling. This systematic review synthesises the current evidence on how antibiotic contamination affects microbial community structure, facilitates antibiotic resistance gene (ARG) proliferation, and dictates biogeochemical consequences in these ecotones. Our analysis confirmed that environmentally relevant concentrations significantly inhibited key nitrifying and denitrifying communities, leading to reduced N-processing rates. Chronic exposure promotes ARG dissemination via horizontal gene transfer and alters community diversity, with prolonged persistence in hyporheic sediments driving nitrate accumulation and elevating the risks of downstream eutrophication and hypoxia. Furthermore, interactions with co-contaminants such as heavy metals and pesticides synergistically accelerate ARG propagation through co-selection mechanisms. Although microbial resilience was observed, chronic, long-term exposure induced significant, often irreversible, shifts in community composition and functional efficiency. This review identifies critical knowledge gaps impeding effective risk mitigation, specifically the limited validation of laboratory findings at the ecosystem scale and the need for a mechanistic understanding of the molecular connections between ARG proliferation and functional N-cycle genes. Future studies should employ integrated multi-omics and advanced biogeochemical-hydrological modelling to address these deficiencies and develop robust strategies to safeguard hyporheic ecological functions.