Obieze Chinedu C, Wani Gowher A, Shah Manzoor A, Reshi Zafar A, Comeau André M, Khasa Damase P
Centre for Forest Research, Institute of Integrative Biology and Systems, Université Laval, Quebec, QC G1V0A6, Canada.
Centre for Forest Research, Institute of Integrative Biology and Systems, Université Laval, Quebec, QC G1V0A6, Canada; Department of Botany, University of Kashmir, Srinagar 190006, Jammu and Kashmir, India.
Sci Total Environ. 2022 Jun 20;826:154292. doi: 10.1016/j.scitotenv.2022.154292. Epub 2022 Mar 4.
Freshwater lakes are important reservoirs and sources of drinking water globally. However, the microbiota, which supports the functionality of these ecosystems is threatened by the influx of nutrients, heavy metals and other toxic chemical substances from anthropogenic activities. The influence of these factors on the diversity, assembly mechanisms and co-occurrence patterns of bacterial communities in freshwater lakes is not clearly understood. Hence, samples were collected from six different impacted lakes in Canada and India and examined by 454-pyrosequencing technology. The trophic status of these lakes was determined using specific chemical parameters. Our results revealed that bacterial diversity and community composition was altered by both the lake water chemistry and geographic distance. Anthropogenic activities pervasively influenced species distribution. Dispersal limitation (32.3%), homogenous selection (31.8%) and drift (20%) accounted for the largest proportions of the bacterial community assembly mechanisms. Homogenous selection increased in lakes with higher nutrient concentration, while stochasticity reduced. Community functional profiles revealed that deterministic processes dominated the assembly mechanisms of phylotypes with higher potential for biodegradation, while stochasticity dominated the assembly of phylotypes with potential for antimicrobial resistance. Bacteroidota (44%) and Proteobacteria (34%) were the most abundant phyla. Co-occurrence network analysis revealed that complexity increased in more impacted lakes, while competition and the nature of anthropogenic activity contributed to species sorting. Overall, this study demonstrates that bacterial community changes in freshwater lakes are linked to anthropogenic activities, with corresponding consequences on the distribution of phylotypes of environmental and human health interest.
淡水湖是全球重要的饮用水储备和水源。然而，维持这些生态系统功能的微生物群正受到来自人为活动的营养物质、重金属和其他有毒化学物质流入的威胁。这些因素对淡水湖细菌群落的多样性、组装机制和共现模式的影响尚不清楚。因此，从加拿大和印度的六个不同受影响湖泊采集了样本，并采用454焦磷酸测序技术进行检测。利用特定化学参数确定了这些湖泊的营养状态。我们的结果表明，湖水化学和地理距离都改变了细菌多样性和群落组成。人为活动对物种分布产生了普遍影响。扩散限制（32.3%）、同质选择（31.8%）和漂移（20%）在细菌群落组装机制中占比最大。在营养浓度较高的湖泊中，同质选择增加，而随机性降低。群落功能概况显示，确定性过程主导了具有较高生物降解潜力的系统发育型的组装机制，而随机性主导了具有抗微生物抗性潜力的系统发育型的组装。拟杆菌门（44%）和变形菌门（34%）是最丰富的门类。共现网络分析表明，受影响越大的湖泊，其复杂性越高，而竞争和人为活动的性质导致了物种分选。总体而言，本研究表明淡水湖中的细菌群落变化与人为活动有关，对具有环境和人类健康意义的系统发育型分布产生相应影响。
