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Distinct gut microbiomes in two polar bear subpopulations inhabiting different sea ice ecoregions

January 11, 2022

Gut microbiomes were analyzed by 16S rRNA gene metabarcoding for polar bears (Ursus maritimus) from the southern Beaufort Sea (SB), where sea ice loss has led to increased use of land-based food resources by bears, and from East Greenland (EG), where persistent sea ice has allowed hunting of ice-associated prey nearly year-round. SB polar bears showed a higher number of total (940 vs. 742) and unique (387 vs. 189) amplicon sequence variants and higher inter-individual variation compared to EG polar bears. Gut microbiome composition differed significantly between the two subpopulations and among sex/age classes, likely driven by diet variation and ontogenetic shifts in the gut microbiome. Dietary tracer analysis using fatty acid signatures for SB polar bears showed that diet explained more intrapopulation variation in gut microbiome composition and diversity than other tested variables, i.e., sex/age class, body condition, and capture year. Substantial differences in the SB gut microbiome relative to EG polar bears, and associations between SB gut microbiome and diet, suggest that the shifting foraging habits of SB polar bears tied to sea ice loss may be altering their gut microbiome, with potential consequences for nutrition and physiology.

Citation Information

Publication Year 2022
Title Distinct gut microbiomes in two polar bear subpopulations inhabiting different sea ice ecoregions
DOI 10.1038/s41598-021-04340-2
Authors Megan Franz, Lyle White, Todd C. Atwood, Kristin L. Laidre, Denis Roy, Sophie Watson, Esteban Gongora, Melissa McKinney
Publication Type Article
Publication Subtype Journal Article
Series Title Scientific Reports
Series Number
Index ID 70230318
Record Source USGS Publications Warehouse
USGS Organization Alaska Science Center Biology MFEB

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