The Alberta Oil Sands Region in Canada is home to one of the largest oil bitumen deposits in the world. The North American river otter (Lontra canadensis) is a top predator with a small home range and is sensitive to disturbances; it has been designated as a sentinel species for the potential impacts of the natural resource exploitation on freshwater ecosystems in the Alberta Oil Sands Region. With an increasing interest in noninvasive biomarkers, recent studies suggest that gut microbiota can be used as a potential biomarker of early biological effects on aquatic wildlife. The goal of the present study was to determine the river otter gut microbial structure related to environmental variables characterizing mining activities and metal body burden. We obtained 18 trapped animals from and surrounding the surface mineable area of the Alberta Oil Sands Region. The gut microbial community structure was characterized using high‐throughput sequencing of 16S rRNA gene amplicon analyses. Trace metal concentrations in the liver were measured by inductively coupled plasma–mass spectrometry. Our study revealed that the gut bacteria of river otters in the Alberta Oil Sands Region clustered in 4 groups dominated by Peptostreptococcaceae, Carnobacteriaceae, Enterobacteriaceae, Clostridiaceae, and Nostocaceae. We show that arsenic, barium, rubidium, liver‐body weight ratio, and δ¹⁵N were associated with each cluster. When comparing affected versus less affected sites, we show that river otter gut bacterial community and structure are significantly related to trophic level of the river otter but not to Alberta Oil Sands Region mining activities. Our study reveals that the gut bacterial dynamics can provide insights into the diet and habitat use of river otters but that more work is needed to use it as a pollution biomarker. Environ Toxicol Chem 2020;39:2516–2526. © 2020 SETAC

中文翻译：

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加拿大亚伯达省油砂地区的北美水獭（Lontra canadensis）的肠道微生物群落结构：与当地环境变量和金属体负担的关系。

加拿大的艾伯塔省油砂地区是世界上最大的石油沥青矿床之一。北美水獭（Lontra canadensis）是家境较小的顶级捕食者，对干扰敏感；由于自然资源开发对艾伯塔省油砂地区的淡水生态系统的潜在影响，它已被指定为前哨物种。随着对非侵入性生物标记物的兴趣日益增加，最近的研究表明，肠道菌群可以用作早期生物对水生野生生物的潜在生物标记物。本研究的目的是确定与水獭肠道微生物结构有关的环境变量，这些环境变量表征了采矿活动和金属矿体的负担。我们从艾伯塔省油砂地区的地表可开采区域及其周围地区捕获了18只被困动物。使用16S rRNA基因扩增子分析的高通量测序来表征肠道微生物群落结构。肝脏中的痕量金属浓度通过电感耦合等离子体质谱法测定。我们的研究表明，艾伯塔省油砂地区的水獭肠道细菌聚集在4个类群中，其中以肽链球菌科，食肉杆菌科，肠杆菌科，梭菌科和野菌科为主。我们显示出砷，钡，rub，肝体重比和δ每个群集关联^15N。当比较受灾地区和受灾较少的地区时，我们发现水獭肠道细菌群落和结构与水獭的营养水平显着相关，而与艾伯塔省油砂地区的采矿活动无关。我们的研究表明，肠道细菌的动力学可以提供有关水獭饮食和栖息地使用的见解，但需要更多的工作才能将其用作污染生物标志物。2020年《环境毒理学》； 39：2516–2526。©2020 SETAC