Laboratory of Environment Biomonitoring, University of Carthage, Faculty of Sciences of Bizerta (FSB), 7021 Zarzouna, Bizerta, Tunisia.
Laboratory of Environment Biomonitoring, University of Carthage, Faculty of Sciences of Bizerta (FSB), 7021 Zarzouna, Bizerta, Tunisia.
Sci Total Environ. 2021 May 20;770:145251. doi: 10.1016/j.scitotenv.2021.145251. Epub 2021 Jan 20.
Trophic web structuring in aquatic sediments is dependent on the biological interactions between metazoans and microbial communities. The presence of pollutants in these biotas can therefore impact the meiofauna structure via the modification of the microbial communities. The current study examined in a laboratory bioassay the response of meiobenthic communities, particularly marine nematode taxa from the Bizerte Lagoon to the effect of the most detected polybrominated diphenyl ether in this aquatic environment, BDE-47. Four doses [D1 (2.5 ppb Dry weight (DW)), D2 (25 ppb DW), D3 (50 ppb DW), and D4 (100 ppb DW)] were gradually applied and sediment microcosms were incubated for 30 days in the presence or absence of meiofauna. Our results show that BDE-47-enriched sediments decreased the meiofaunal taxa and bacterial abundance. A lower taxonomic diversity of the nematodes' general structure was observed with all doses used. The numerical analysis of the two dimensional (2D) non-metric multidimensional scaling (nMDS) plots and the evolution of the relative abundances of each functional group of nematode genus assemblages revealed that the abundance of all biological traits was modified. Nevertheless, only three of the functional traits, adult length, feeding group, and amphid shape, showed a clear difference between the control and the treated microcosms. The similarity percentage analysis (SIMPER) revealed that the average dissimilarity between nematode genera communities and biological traits increased with BDE-47-enriched sediments. The nMDS second-stage ordination of inter-matrix rank correlations for matrices including genera and biological traits showed that the amphid shape was the functional trait closest to the generic distribution. Finally, the Principal Component Analysis (PCA) for the nematode biological traits and bacteria indicated a positive correlation of these microbes with the functional groups [1A, Cr, and ef], and a negative correlation only with the "cla"-type tail shape.
水生沉积物中的营养级结构依赖于后生动物和微生物群落之间的生物相互作用。因此，这些生物群中的污染物的存在可以通过改变微生物群落来影响小型底栖动物的结构。本研究在实验室生物测定中检查了海洋线虫类群等小型底栖动物群落对该水生环境中最检测到的多溴二苯醚（BDE-47）的影响，该群落来自比塞大泻湖。四个剂量[D1（2.5 ppb 干重（DW）），D2（25 ppb DW），D3（50 ppb DW）和 D4（100 ppb DW）]逐渐施加，在存在或不存在小型底栖动物的情况下，将沉积物微宇宙孵育 30 天。我们的结果表明，富含 BDE-47 的沉积物减少了小型底栖动物的类群和细菌丰度。使用所有剂量观察到线虫一般结构的分类多样性较低。二维（2D）非度量多维尺度（nMDS）图的数值分析和线虫属组合的每个功能群相对丰度的演变表明，所有生物特征的丰度都发生了变化。然而，只有三个功能特征，即成虫长度、摄食组和乳突形状，在对照和处理微宇宙之间表现出明显差异。相似性百分比分析（SIMPER）显示，随着富含 BDE-47 的沉积物，线虫属群落和生物特征之间的平均差异增加。包括属和生物特征的矩阵之间的矩阵内等级相关的 nMDS 第二阶段排序表明，乳突形状是最接近属分布的功能特征。最后，线虫生物特征和细菌的主成分分析（PCA）表明，这些微生物与功能组[1A、Cr 和 ef]呈正相关，仅与“cla”-型尾形状呈负相关。
