The Gut Microbial Community Structure of the North American River Otter (Lontra canadensis) in the Alberta Oil Sands Region in Canada: Relationship with Local Environmental Variables and Metal Body Burden

Abstract

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 δ 15 N 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.

Characterizing the Gut Microbiota of Eurasian Otter (Lutra lutra chinensis) and Snub-Nosed Monkey (Rhinopithecus roxellana) to Enhance Conservation Practices in the Foping National Nature Reserve of China

“…We have also shown that the otter fecal microbiome is composed mainly of Firmicutes , Proteobacteria , and Bacteroidota . This gut bacterial structure is similar to that of the American mink and Eurasian river otter gut microbiota [ 20 ]. In wild Eurasian otter feces, Bacteroides were found to be more abundant [ 21 ].…”

The gut microbiome of wild American marten in the Upper Peninsula of Michigan

“…Here we present the first characterization of the gut microbiome in wild marten. In contrast to most mammalian gut microbiome studies, which have generally focused on omnivorous and herbivorous species with ceca, and similar to the findings of a study of the gut microbiome of North American river otters [ 75 ], the marten gut community is dominated by Firmicutes (52.35%) and Proteobacteria (45.31%). Further, the marten gut microbiome comprises only 12 major genera ( Table 2 ) that tend to be generalist bacteria previously associated with early stages of succession in the gastrointestinal tract ( Clostridium sensu stricto 1 and Lactobacillus ; [ 76 ]) or disease ( Clostridium sensu stricto 1 [ 77 ]; Escherichia-Shigella [ 78 ]; Mycoplasma [ 79 ]).…”

Non-invasive biomonitoring of polar bear feces can be used to estimate concentrations of metals of concern in traditional food

“…Wildlife biomonitoring has long been used to quantify levels of contaminants in the environment and ascribe risk using key sentinel species [12][13][14]. While invasive or destructive samples are used, as is the case for the collection of liver or muscle samples, there have recently been initiatives to move towards non-lethal and non-invasive biomonitoring techniques, including the use of fur [15,16] and feces [17].…”