# Review of the Effects of Antibiotics on Nitrogen Cycle and Greenhouse Gas Emissions in Aquaculture Water

## TL;DR

This review explores how antibiotics in aquaculture disrupt nitrogen cycles and increase greenhouse gas emissions, highlighting the need for better pollution control strategies.

## Contribution

The paper synthesizes recent findings on how various antibiotics affect microbial processes and greenhouse gas emissions in aquaculture systems.

## Key findings

- Antibiotics reduce nitrogen-removal efficiency by 25–55% and promote toxic intermediate accumulation.
- Antibiotics enhance emissions of nitrous oxide (N2O) and methane (CH4).
- Environmental factors and co-contaminants like heavy metals and microplastics amplify ecological risks by 20–40%.

## Abstract

Aquaculture systems face escalating ecological risks due to the widespread use and persistence of antibiotics, which disrupt microbial-mediated nitrogen cycling and exacerbate greenhouse gas (GHG) emissions. This review synthesizes the recent research on how common antibiotics, such as sulfonamides, quinolones, tetracyclines, and macrolides, with the concentration ranging from μg/L to mg/L, alter microbial community structure, functional gene expression (e.g., amoA, nirK, and nosZ), and key nitrogen transformation processes. These disruptions inhibit nitrogen-removal efficiency by 25–55%, promote the accumulation of toxic intermediates (e.g., NH4+ and NO2−), and enhance emissions of potent GHGs of nitrous oxide (N2O) and methane (CH4). The effects are influenced by antibiotic type; concentration; environmental conditions; and interactions with co-contaminants such as heavy metals (Cu2+ and Pb2+ at 50–200 μg/L) and microplastics (0.1–10 mg/L), which can synergistically amplify ecological risks by 20–40%. The research in this field has largely focused on the toxicity of individual antibiotics, so significant gaps remain regarding combined pollution effects, long-term microbial adaptation, and molecular-scale mechanisms. This review synthesizes research on the impacts of aquaculture antibiotics on microbial nitrogen cycling and GHG emissions, identifying key mechanisms and research gaps. Its significance lies in laying a scientific foundation for integrated antibiotics pollution control strategies and bridging basic research with practical aquaculture management to advance the sustainability of aquaculture ecosystems.