Cheaib Bachar, Le Boulch Malo, Mercier Pierre-Luc, Derome Nicolas
Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec, QC, Canada.
GenPhySE, Institut National de la Recherche Agronomique, Université de Toulouse, INPT, ENVT, Castanet-Tolosan, France.
Front Microbiol. 2018 May 3;9:869. doi: 10.3389/fmicb.2018.00869. eCollection 2018.
Adaptation of microbial communities to anthropogenic stressors can lead to reductions in microbial diversity and disequilibrium of ecosystem services. Such adaptation can change the molecular signatures of communities with differences in taxonomic and functional composition. Understanding the relationship between taxonomic and functional variation remains a critical issue in microbial ecology. Here, we assessed the taxonomic and functional diversity of a lake metacommunity system along a polymetallic pollution gradient caused by 60 years of chronic exposure to acid mine drainage (AMD). Our results highlight three adaptive signatures. First, a signature of taxon-function decoupling was detected in the microbial communities of moderately and highly polluted lakes. Second, parallel shifts in taxonomic composition occurred between polluted and unpolluted lakes. Third, variation in the abundance of functional modules suggested a gradual deterioration of ecosystem services (i.e., photosynthesis) and secondary metabolism in highly polluted lakes. Overall, changes in the abundance of taxa, function, and more importantly the polymetallic resistance genes such as , were correlated with trace metal content (mainly Cadmium) and acidity. Our findings highlight the impact of polymetallic pollution gradient at the lowest trophic levels.
微生物群落对人为压力源的适应可能导致微生物多样性降低和生态系统服务失衡。这种适应会改变群落的分子特征，导致分类学和功能组成上的差异。了解分类学变异与功能变异之间的关系仍然是微生物生态学中的一个关键问题。在此，我们沿着因60年长期暴露于酸性矿山排水（AMD）而形成的多金属污染梯度，评估了一个湖泊集合群落系统的分类学和功能多样性。我们的结果突出了三个适应性特征。首先，在中度和高度污染湖泊的微生物群落中检测到分类单元-功能解耦特征。其次，污染湖泊和未污染湖泊之间出现了分类组成的平行变化。第三，功能模块丰度的变化表明，在高度污染的湖泊中，生态系统服务（即光合作用）和次生代谢逐渐退化。总体而言，分类单元、功能丰度的变化，更重要的是诸如多金属抗性基因等的丰度变化，与痕量金属含量（主要是镉）和酸度相关。我们的研究结果突出了多金属污染梯度在最低营养级水平上的影响。
