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dc.contributor.authorBourgeon, Sophie
dc.contributor.authorRiemer, Astrid Kolind
dc.contributor.authorTartu, Sabrina
dc.contributor.authorAars, Jon
dc.contributor.authorPolder, Anuschka
dc.contributor.authorJenssen, Bjørn Munro
dc.contributor.authorRoutti, Heli Anna Irmeli
dc.date.accessioned2018-03-06T12:49:52Z
dc.date.available2018-03-06T12:49:52Z
dc.date.issued2017-06-11
dc.description.abstractAs apex predators, polar bears (Ursus maritimus) are among the most heavily polluted organisms in the Arctic. In addition to this anthropogenic stressor, climate warming has been shown to negatively affect their body condition, reproductive output and survival. Among potential underlying physiological mechanisms, thyroid hormones (THs), which control thermoregulation, metabolism and reproduction, can be affected by a variety of both natural and anthropogenic factors. While THs have been extensively used as proxies for pollution exposure in mammals, including polar bears, there is a lack of knowledge of their natural variations. In this context, we examined seasonal variations in body condition and circulating TH concentrations in free-ranging female polar bears. Females with variable reproductive status (i.e., solitary, with cubs of the year or with yearlings) were sampled from locations with contrasted sea ice conditions. Furthermore, we studied THs in relation to levels of organo-halogenated contaminants. As predicted, solitary females were in better condition than females caring for offspring, especially in spring. In addition, TH levels were lower in autumn compared to spring, although this seasonal effect was mainly observed in solitary females. Finally, the negative relationships between organochlorine and perfluoroalkyl substances and some THs suggest a possible alteration of homeostasis of THs. Since the latter relationships were only observed during spring, we emphasize the importance of considering the ecological factors when using THs as proxies for pollution exposure. Yet, the combined effects of natural and anthropogenic stressors on THs might impair the ability of polar bears to adapt to ongoing climate changes.en_US
dc.descriptionAccepted manuscript version. Published version available in <a href=https://doi.org/10.1016/j.envres.2017.05.034> Environmental Research 2017, 158: 94-104. </a>en_US
dc.identifier.citationBourgeon, S., Riemer, A. K., Tartu, S., Aars, J., Polder, A., Jenssen, B. M. & Routti, H. A. I. (2017). Potentiation of ecological factors on the disruption of thyroid hormones by organo-halogenated contaminants in female polar bears (Ursus maritimus) from the Barents Sea. Environmental Research,158:94-104.en_US
dc.identifier.cristinIDFRIDAID 1475304
dc.identifier.doi10.1016/j.envres.2017.05.034
dc.identifier.issn0013-9351
dc.identifier.issn1096-0953
dc.identifier.urihttps://hdl.handle.net/10037/12267
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalEnvironmental Research
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/POLARPROG/216568/NORWAY/Synergistic effects of sea ice-free periods and contaminant exposure on energy metabolism in polar bears//en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økotoksikologi: 489en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecotoxicology: 489en_US
dc.subjectBreeding statusen_US
dc.subjectClimate changeen_US
dc.subjectFastingen_US
dc.subjectOrganochlorinesen_US
dc.subjectPerfluoroalkyl substancesen_US
dc.titlePotentiation of ecological factors on the disruption of thyroid hormones by organo-halogenated contaminants in female polar bears (Ursus maritimus) from the Barents Sea.en_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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