Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS, France; Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS, France.
Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS, France.
Sci Total Environ. 2014 Nov 15;499:327-35. doi: 10.1016/j.scitotenv.2014.08.048. Epub 2014 Sep 6.
Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold(®) contaminated water (960 g L(-1) of the herbicide S-metolachlor, >80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was >40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93-97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p=0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems.
有关湿地细菌群落的知识，在农药污染和水文状况的背景下还很缺乏。我们研究了接收受 Mercantor Gold(®)污染水（960 g L(-1) 的除草剂 S-甲草氯，S-对映体 >80%）的人工湿地中的细菌组成，这些湿地采用连续流或批处理模式运行，以评估水力状况的影响。在连续流湿地中，S-甲草氯的去除率>40%，而在批处理湿地中，几乎完全去除了 S-甲草氯（93-97%）。乙磺酸和恶嗪酸降解产物的检测进一步表明了两种湿地中的 S-甲草氯生物降解。末端限制性片段长度多态性（T-RFLP）和 454 焦磷酸测序分析了主要细菌种群。细菌谱在实验的前 35 天发生了演变，从与进水相似的组成开始，利用硝酸盐，以及在较小程度上利用硫酸盐和锰作为微生物代谢的末端电子受体。变形菌门是最丰富的门，β-、α-和γ-变形菌分别占总细菌丰度的 26%、19%和 17%。在连续流湿地中，湿地水中的细菌组成随时间逐渐变化，而在批处理湿地中则更为突然。两个系统中总体细菌水结构的差异虽然不大但却很显著（p=0.008），S-甲草氯、硝酸盐和总无机碳浓度与细菌谱的变化相关。总之，这些结果强调了细菌组成谱及其动态可作为湿地系统中除草剂暴露和水力干扰的生物指标。
