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Arctic health: Investigating the gut microbiota and parasite diversity of Arctic species

Watson, Sophie Elizabeth 2020. Arctic health: Investigating the gut microbiota and parasite diversity of Arctic species. PhD Thesis, Cardiff University.
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The Arctic faces some of the most rapid and extreme climatic changes on earth, and within forthcoming years these changes are expected only to accelerate. The evolution of Arctic species has been shaped by a turbulent climatic history encompassing multiple cycles of glacial advance and retreat, and associated changes in sea-ice extent. As such, many Arctic species are well adapted to climatic extremes, but remain poorly adapted to secondary ecological stressors such as competition, contaminants, parasites and disease, leaving them vulnerable. Despite this, there remains a paucity of data addressing two major influencers of health, i) the composition of host gut microbiota and ii) parasitic infection. Here, these shortcomings are addressed using a whole-Arctic approach and two model apex species; the polar bear (Ursus maritimus) and the wolverine (Gulo gulo). Within this thesis, a combination of data mining, high-throughput sequencing, and traditional parasite count approaches are used to i) establish the parasite diversity and data deficient species across the whole Arctic, and ii) to determine the gut bacterial communities and parasite diversity of polar bears and wolverines in association with contaminant profiles, changes in land use and diet. Firstly, this thesis shows that humans and domestic dogs are hubs for parasites within the Arctic, while other species (even those which are ambassadors of the Arctic, e.g. polar bears) remain poorly studied. Secondly, this thesis is the first to conduct a full assessment of the gastrointestinal parasite diversity of Arctic wolverines, finding that the distribution of their predominant helminth infection, Baylisascaris devosi, although limited by latitude, is present in individuals from the Arctic tundra, which was previously unrecorded. Furthermore, we describe how the composition of bacterial communities within the gut of wolverines may reflect their ability to scavenge a wide variety of prey and tissue types. In polar bears, we show that the gut microbiota differs significantly in individuals using onshore coastal regions, compared to those that exhibit their typical behaviour of remaining offshore year-round. Finally, we demonstrate that differences in diet-driven mercury levels linked with on- versus offshore behaviour are associated with significant changes to polar bear microbiota. Composition and diversity of gut bacteria is deeply rooted in the evolution of the host. As such, although little is known of the gut microbiota of free ranging species, it is apparent that changes to the gut microbiota may influence health and ultimately survival. By establishing what constitutes typical polar bear and wolverine gut microbiota, this thesis provides a biomarker against which to measure the effects of current and future environmental and anthropogenic stressors. Furthermore, this thesis

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Biosciences
Subjects: Q Science > Q Science (General)
Funders: NERC
Date of First Compliant Deposit: 12 March 2021
Last Modified: 12 Mar 2021 16:35

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