Data_Sheet_6_Taxon-Function Decoupling as an Adaptive Signature of Lake Microbial Metacommunities Under a Chronic Polymetallic Pollution Gradient.XLSX

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 copA, copB, czcA, cadR, cCusA, were correlated with trace metal content (mainly Cadmium) and acidity. Our findings highlight the impact of polymetallic pollution gradient at the lowest trophic levels.

微生物群落对人为胁迫因子的适应，可导致微生物多样性降低与生态系统服务功能失衡。这类适应可改变群落的分子特征，使其分类学与功能组成产生差异。阐明分类学变异与功能变异之间的关联，仍是微生物生态学领域的核心议题。本研究针对一处受60年慢性酸性矿山排水（AMD）污染形成的多金属污染梯度的湖泊集合群落系统，评估其分类学与功能多样性。本研究结果揭示了三类适应性特征：其一，在中度与重度污染湖泊的微生物群落中，检测到分类-功能解偶联特征；其二，污染与未污染湖泊的微生物群落分类学组成呈现平行分化格局；其三，功能模块丰度的变化表明，重度污染湖泊的生态系统服务（即光合作用）与次级代谢过程逐渐衰退。总体而言，类群丰度、功能丰度的变化，更关键的是copA、copB、czcA、cadR、cCusA等多金属抗性基因的丰度变化，与痕量金属（主要为镉）含量及水体酸度显著相关。本研究结果凸显了多金属污染梯度对最低营养级生物群落的影响。