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Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape.
Environ Sci Technol. 2020 03 03; 54(5):2780-2789.ES

Abstract

Polar bears (Ursus maritimus) and ringed seals (Pusa hispida) have a strong predator-prey relationship and are facing climate-associated Arctic habitat loss and harmful dietary exposure to total mercury (THg) and other pollutants. However, little is known about whether both species inhabiting the same area exhibit similar temporal patterns in Hg concentration, niche dynamics, and body fat indices. We used THg, δ13C, and δ15N values of western Hudson Bay polar bear hair (2004-2016) and ringed seal muscle samples (2003-2015) to investigate temporal trends of these variables and multidimensional niche metrics, as well as body fat indices for both species. We found a decline in THg concentration (by 3.8% per year) and δ13C (by 1.5‰) in ringed seals suggesting a change in feeding habits and carbon source use over time, whereas no significant changes occurred in polar bears. In contrast, the polar bear 3-dimensional niche size decreased by nearly half with no change in ringed seal niche size. The δ13C spacing between both species increased by approximately 1.5× suggesting different responses to annual changes in sympagic-pelagic carbon source production. Ringed seal body fat index was higher in years of earlier sea ice breakup with no change occurring in polar bears. These findings indicate that both species are responding differently to a changing environment suggesting a possible weakening of their predator-prey relationship in western Hudson Bay.

Authors+Show Affiliations

University of Manitoba, Winnipeg, Manitoba MB R3T 2N2, Canada. Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada.Environment and Climate Change Canada, Winnipeg, Manitoba MB R3B 2B4, Canada.Environment and Climate Change Canada, Edmonton, Alberta AB T5J 0J4, Canada.Environment and Climate Change Canada, Burlington, Ontario ON L7S 1A1, Canada.University of Alberta, Edmonton, Alberta AB T6G 2R3, Canada.University of Alberta, Edmonton, Alberta AB T6G 2R3, Canada.Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada.Environment and Climate Change Canada, Montreal, Quebec QC H2Y 2E7, Canada.Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada.University of Manitoba, Winnipeg, Manitoba MB R3T 2N2, Canada.York University, Toronto, Ontario ON M3J 1P3, Canada.York University, Toronto, Ontario ON M3J 1P3, Canada.Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

32046488

Citation

Yurkowski, David J., et al. "Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape." Environmental Science & Technology, vol. 54, no. 5, 2020, pp. 2780-2789.
Yurkowski DJ, Richardson ES, Lunn NJ, et al. Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape. Environ Sci Technol. 2020;54(5):2780-2789.
Yurkowski, D. J., Richardson, E. S., Lunn, N. J., Muir, D. C. G., Johnson, A. C., Derocher, A. E., Ehrman, A. D., Houde, M., Young, B. G., Debets, C. D., Sciullo, L., Thiemann, G. W., & Ferguson, S. H. (2020). Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape. Environmental Science & Technology, 54(5), 2780-2789. https://doi.org/10.1021/acs.est.9b06656
Yurkowski DJ, et al. Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape. Environ Sci Technol. 2020 03 3;54(5):2780-2789. PubMed PMID: 32046488.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape. AU - Yurkowski,David J, AU - Richardson,Evan S, AU - Lunn,Nicholas J, AU - Muir,Derek C G, AU - Johnson,Amy C, AU - Derocher,Andrew E, AU - Ehrman,Ashley D, AU - Houde,Magali, AU - Young,Brent G, AU - Debets,Cassandra D, AU - Sciullo,Luana, AU - Thiemann,Gregory W, AU - Ferguson,Steven H, Y1 - 2020/02/21/ PY - 2020/2/13/pubmed PY - 2020/3/17/medline PY - 2020/2/13/entrez SP - 2780 EP - 2789 JF - Environmental science & technology JO - Environ Sci Technol VL - 54 IS - 5 N2 - Polar bears (Ursus maritimus) and ringed seals (Pusa hispida) have a strong predator-prey relationship and are facing climate-associated Arctic habitat loss and harmful dietary exposure to total mercury (THg) and other pollutants. However, little is known about whether both species inhabiting the same area exhibit similar temporal patterns in Hg concentration, niche dynamics, and body fat indices. We used THg, δ13C, and δ15N values of western Hudson Bay polar bear hair (2004-2016) and ringed seal muscle samples (2003-2015) to investigate temporal trends of these variables and multidimensional niche metrics, as well as body fat indices for both species. We found a decline in THg concentration (by 3.8% per year) and δ13C (by 1.5‰) in ringed seals suggesting a change in feeding habits and carbon source use over time, whereas no significant changes occurred in polar bears. In contrast, the polar bear 3-dimensional niche size decreased by nearly half with no change in ringed seal niche size. The δ13C spacing between both species increased by approximately 1.5× suggesting different responses to annual changes in sympagic-pelagic carbon source production. Ringed seal body fat index was higher in years of earlier sea ice breakup with no change occurring in polar bears. These findings indicate that both species are responding differently to a changing environment suggesting a possible weakening of their predator-prey relationship in western Hudson Bay. SN - 1520-5851 UR - https://www.unboundmedicine.com/medline/citation/32046488/Contrasting_Temporal_Patterns_of_Mercury_Niche_Dynamics_and_Body_Fat_Indices_of_Polar_Bears_and_Ringed_Seals_in_a_Melting_Icescape_ L2 - https://doi.org/10.1021/acs.est.9b06656 DB - PRIME DP - Unbound Medicine ER -