Département de Géomatique Appliquée, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; Département de Géomatique Appliquée, CARTEL - Centre d'Applications et de Recherche en TELédétection, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; Département de Sciences Biologiques, GRIL - Groupement de Recherche Interuniversitaire en Limnologie, Université de Montréal, Campus MIL, Montréal, QC H3C 3J7, Canada.
Département de Sciences Biologiques, GRIL - Groupement de Recherche Interuniversitaire en Limnologie, Université de Montréal, Campus MIL, Montréal, QC H3C 3J7, Canada; Department of Biology, Concordia University, Montréal, QC H4B 1R6, Canada.
Water Res. 2023 Mar 1;231:119596. doi: 10.1016/j.watres.2023.119596. Epub 2023 Jan 9.
Lakes are sentinels of environmental changes within their watersheds including those induced by a changing climate and anthropogenic activities. In particular, contamination originating from point or non-point sources (NPS) within watersheds might be reflected in changes in the bacterial composition of lake water. We assessed the abundance of potentially pathogenic bacteria (PPB) sampled in 413 lakes within 8 southern Canadian ecozones that represent a wide diversity of lakes and watershed land use. The study objectives were (1) to explore the diversity of PPB; (2) to build a fecal multi-indicator from a cluster of co-occurring PPB; and (3) to predict the fecal multi-indicator over thousands of lakes. We identified bacterial taxa based on 16S rRNA amplicon sequencing and clustered 33 PPB matching taxa in the Canadian ePATHogen database using a Sørensen dissimilarity index on binary data across the sampled lakes. One cluster contained Erysipelothrix, Desulfovibrio, Bacteroides, Vibrio and Acholeplasma and was related to the NPS fraction of agriculture and pasture within the watershed as its main driver and thus it was determined as the fecal multi-indicator. We subsequently developed a fecal multi-indicator predictive model across 200 212 southern Canadian lakes which explained 55.1% of the deviance. Mapping the predictions showed higher fecal multi-indicator abundances in the Prairies and Boreal Plains compared to the other ecozones. These results represent the first attempt to map a potential fecal multi-indicator at the continental scale, which may be further improved in the future. Lastly, the study demonstrates the capacity of a multi-disciplinary approach leveraging both datasets derived from remote sensing and DNA sequencing to provide mapping information for public health governmental policies.
湖泊是其流域内环境变化的哨兵，包括由气候变化和人为活动引起的变化。特别是，流域内点源或非点源（NPS）的污染可能反映在湖水细菌组成的变化上。我们评估了在加拿大南部 8 个生态区的 413 个湖泊中采样的潜在致病细菌（PPB）的丰度，这些湖泊代表了广泛的湖泊和流域土地利用类型。研究目的是：（1）探索 PPB 的多样性；（2）从一组共存的 PPB 中构建粪便多指标；（3）预测数千个湖泊的粪便多指标。我们根据 16S rRNA 扩增子测序确定细菌分类群，并使用基于二进制数据的 Sørensen 不相似性指数对加拿大 ePATHogen 数据库中的 33 个与匹配分类群的 PPB 进行聚类。一个聚类包含红斑丹毒丝菌、脱硫弧菌、拟杆菌、弧菌和无壁菌，与流域内农业和牧场的 NPS 部分有关，是其主要驱动因素，因此被确定为粪便多指标。随后，我们在 200212 个加拿大南部湖泊上开发了粪便多指标预测模型，该模型解释了 55.1%的偏差。预测图显示，草原和北方森林平原的粪便多指标丰度较高，而其他生态区则较低。这些结果代表了首次在大陆尺度上绘制潜在粪便多指标的尝试，未来可能会进一步改进。最后，该研究展示了一种多学科方法的能力，该方法利用了遥感和 DNA 测序产生的两个数据集，为公共卫生政府政策提供制图信息。
