Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China.
CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Laboratory of Physical Chemistry, University of Abomey-Calavi, Republic of Benin, Cotonou 01 BP 4521, Benin.
Environ Int. 2023 Aug;178:108118. doi: 10.1016/j.envint.2023.108118. Epub 2023 Jul 26.
The influence of vertical changes in water depth on emerging pollutants distribution and microbial food web remains elusive. We investigated the influence of vertical transition in water depth on the environmental variables, antibiotics and antibiotic resistomes, and microbial community structures in estuary and marine ecosystems (0-50 m). Stepwise multiple linear regression model showed that among investigated environmental variables, change in water salinity was the most influential factor dictating the fluoroquinolone and macrolides concentrations, while dissolved oxygen and turbidity were the key influencers of sulfonamides and beta-lactam concentrations, respectively. Bacterial and eukaryotic diversity and niche breadth significantly increased with the increasing water depth. Ecosystem food web structure at the bottom depths was more stable than at the middle and surface depths. At the surface depth, the top 5 keystone genera were Cryothecomonas, Syndiniales, Achromobacter, Pseudopirsonia, and Karlodinium. Whereas Eugregarinorida, Neptuniibacter, Mychonastes, Novel_Apicomplexa_Class_1, Aplanochytrium and Dietzia, Halodaphnea, Luminiphilus, Aplanochytrium, Maullinia dominated the top 5 genera at the middle and the bottom depth, respectively. Absolute abundance of antibiotic resistance genes (ARGs) was drastically increased at the surface depth compared with the middle and bottom depths. Abundance of the top 10 ARGs and mobile genetic elements (MGEs) detected including tnpA-05, aadA2-03, mexF, aadA1, intI-1(clinic), qacEdelta1-02, aadA-02, qacEdelta1-01, cmlA1-01, and aadA-01 were amplified at the surface depth. This study demonstrated that ARGs abundance was disproportionate to bacterial diversity, and anthropogenic disturbances, confinement, MGEs, and ecosystem stability play primary roles in the fate of ARGs. The findings of this study also implicate that vertical changes in the water depth on environmental conditions can influence antibiotic concentrations and microbial community dramatically.
水深垂直变化对新兴污染物分布和微生物食物网的影响仍不清楚。我们调查了水深垂直变化对河口和海洋生态系统（0-50 m）中环境变量、抗生素和抗生素抗性组以及微生物群落结构的影响。逐步多元线性回归模型表明，在所研究的环境变量中，盐度变化是决定氟喹诺酮类和大环内酯类浓度的最主要影响因素，而溶解氧和浊度分别是磺胺类和β-内酰胺类浓度的关键影响因素。细菌和真核生物多样性和生态位宽度随水深的增加而显著增加。底部深度的生态系统食物网结构比中部和表面深度更稳定。在表面深度，前 5 个关键属是 Cryothecomonas、Syndiniales、Achromobacter、Pseudopirsonia 和 Karlodinium。而 Eugregarinorida、Neptuniibacter、Mychonastes、Novel_Apicomplexa_Class_1、Aplanochytrium 和 Dietzia、Halodaphnea、Luminiphilus、Aplanochytrium、Maullinia 则分别是中部和底部深度的前 5 个优势属。与中部和底部深度相比，表面深度的抗生素抗性基因（ARGs）绝对丰度急剧增加。检测到的前 10 个 ARGs 和移动遗传元件（MGEs）的丰度包括 tnpA-05、aadA2-03、mexF、aadA1、intI-1（临床）、qacEdelta1-02、aadA-02、qacEdelta1-01、cmlA1-01 和 aadA-01，在表面深度扩增。本研究表明，ARGs 的丰度与细菌多样性不成比例，人为干扰、限制、MGEs 和生态系统稳定性在 ARGs 的命运中起主要作用。本研究的结果还表明，水深的垂直变化对环境条件有很大影响，可以显著影响抗生素浓度和微生物群落。
