Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears

Thesis (M.S.) University of Alaska Fairbanks, 2006 Dietary pathways expose polar bears to a variety of contaminant profiles and concentrations, ranging from bowhead whale (Balaena mysticetus) as one of the least contaminated marine mammals to the more highly contaminated upper trophic level ringed s...

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Main Author: Bentzen, Torsten W.
Format: Thesis
Language:English
Published: 2006
Subjects:
Online Access:http://hdl.handle.net/11122/5509
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record_format openpolar
spelling ftunivalaska:oai:scholarworks.alaska.edu:11122/5509 2023-05-15T15:36:01+02:00 Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears Bentzen, Torsten W. 2006-12 http://hdl.handle.net/11122/5509 en_US eng http://hdl.handle.net/11122/5509 Department of Biology and Wildlife Thesis ms 2006 ftunivalaska 2023-02-23T21:36:27Z Thesis (M.S.) University of Alaska Fairbanks, 2006 Dietary pathways expose polar bears to a variety of contaminant profiles and concentrations, ranging from bowhead whale (Balaena mysticetus) as one of the least contaminated marine mammals to the more highly contaminated upper trophic level ringed seal (Phoca hispida) which represent the majority of their annual diet. We used stable isotopes [delta]¹⁵N and [delta]¹³C to estimate trophic status of 139 free-ranging polar bears sampled along Alaska's Beaufort Sea coast in spring 2003 and 2004. The [delta]¹⁵N values of polar bear packed blood cells ranged from 18.2% to 21.4% with a mean of 19.5% (SD=0.7) in 2003 and 19.9% (SD=0.7) in 2004. Two-element three-source mixing models indicated that lower trophic level prey, such as scavenged bowhead whale carcasses, may have composed 11-26% (95% CI) of the diet in 2003, and -2-14% (95% CI) of the diet in 2004. Organochlorine (OC) concentrations in subcutaneous adipose tissue were determined for 47 of the polar bears sampled in 2003 and compared to trophic position ([delta]¹⁵N). Although many OCs appear not to biomagnify in polar bears, we found positive relationships with [delta]¹⁵N in both sexes between concentrations of several highly recalcitrant OCs in models incorporating age, lipid content, and [delta]¹³C. [Delta]¹⁵N was important in explaining variation in OC concentrations, indicating structural differences in food webs and biomagnification of OCs among polar bears related to their sex, age, and the apparent use of lower trophic level prey. 1. Variation in winter feeding ecology of southern Beaufort Sea polar bears inferred from stable isotope analysis -- 2. Dietary biomagnification of organochlorine contaminants in Alaskan polar bears. Thesis Balaena mysticetus Beaufort Sea bowhead whale Phoca hispida ringed seal Alaska University of Alaska: ScholarWorks@UA Fairbanks
institution Open Polar
collection University of Alaska: ScholarWorks@UA
op_collection_id ftunivalaska
language English
description Thesis (M.S.) University of Alaska Fairbanks, 2006 Dietary pathways expose polar bears to a variety of contaminant profiles and concentrations, ranging from bowhead whale (Balaena mysticetus) as one of the least contaminated marine mammals to the more highly contaminated upper trophic level ringed seal (Phoca hispida) which represent the majority of their annual diet. We used stable isotopes [delta]¹⁵N and [delta]¹³C to estimate trophic status of 139 free-ranging polar bears sampled along Alaska's Beaufort Sea coast in spring 2003 and 2004. The [delta]¹⁵N values of polar bear packed blood cells ranged from 18.2% to 21.4% with a mean of 19.5% (SD=0.7) in 2003 and 19.9% (SD=0.7) in 2004. Two-element three-source mixing models indicated that lower trophic level prey, such as scavenged bowhead whale carcasses, may have composed 11-26% (95% CI) of the diet in 2003, and -2-14% (95% CI) of the diet in 2004. Organochlorine (OC) concentrations in subcutaneous adipose tissue were determined for 47 of the polar bears sampled in 2003 and compared to trophic position ([delta]¹⁵N). Although many OCs appear not to biomagnify in polar bears, we found positive relationships with [delta]¹⁵N in both sexes between concentrations of several highly recalcitrant OCs in models incorporating age, lipid content, and [delta]¹³C. [Delta]¹⁵N was important in explaining variation in OC concentrations, indicating structural differences in food webs and biomagnification of OCs among polar bears related to their sex, age, and the apparent use of lower trophic level prey. 1. Variation in winter feeding ecology of southern Beaufort Sea polar bears inferred from stable isotope analysis -- 2. Dietary biomagnification of organochlorine contaminants in Alaskan polar bears.
format Thesis
author Bentzen, Torsten W.
spellingShingle Bentzen, Torsten W.
Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears
author_facet Bentzen, Torsten W.
author_sort Bentzen, Torsten W.
title Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears
title_short Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears
title_full Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears
title_fullStr Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears
title_full_unstemmed Winter feeding ecology and biomagnification of organochlorine contaminants in Alaska polar bears
title_sort winter feeding ecology and biomagnification of organochlorine contaminants in alaska polar bears
publishDate 2006
url http://hdl.handle.net/11122/5509
geographic Fairbanks
geographic_facet Fairbanks
genre Balaena mysticetus
Beaufort Sea
bowhead whale
Phoca hispida
ringed seal
Alaska
genre_facet Balaena mysticetus
Beaufort Sea
bowhead whale
Phoca hispida
ringed seal
Alaska
op_relation http://hdl.handle.net/11122/5509
Department of Biology and Wildlife
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