Blar i forfatter "Welker, Jeffrey Martin"

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    • Choose your poison – Space-use strategy influences pollutant exposure in Barents Sea polar bears 

      Tartu, Sabrina; Aars, Jon; Andersen, Magnus; Polder, Anuschka; Bourgeon, Sophie; Merkel, Benjamin; Lowther, Andrew D.; Bytingsvik, Jenny; Welker, Jeffrey Martin; Derocher, Andrew E.; Jenssen, Bjørn Munro; Routti, Heli (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-24)
      Variation in space-use is common within mammal populations. In polar bears, Ursus maritimus, some individuals follow the sea ice (offshore bears) whereas others remain nearshore yearlong (coastal bears). We studied pollutant exposure in relation to space-use patterns (offshore vs coastal) in adult female polar bears from the Barents Sea equipped with satellite collars (2000–2014, n = 152). First, ...

    • Diet and metabolic state are the main factors determining concentrations of perfluoroalkyl substances in female polar bears from Svalbard 

      Tartu, Sabrina; Bourgeon, Sophie; Aars, Jon; Andersen, Magnus; Lone, Karen; Jenssen, Bjørn Munro; Polder, Anuschka; Thiemann, Gregory W.; Torget, Vidar; Welker, Jeffrey Martin; Routti, Heli Anna Irmeli (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-03)
      Perfluoroalkyl substances (PFASs) have been detected in organisms worldwide, including Polar Regions. The polar bear (Ursus maritimus), the top predator of Arctic marine ecosystems, accumulates high concentrations of PFASs, which may be harmful to their health. The aim of this study was to investigate which factors (habitat quality, season, year, diet, metabolic state [i.e. feeding/fasting], breeding ...

    • Geographical area and life history traits influence diet in an Arctic marine predator 

      Tartu, Sabrina; Bourgeon, Sophie; Aars, Jon; Andersen, Magnus; Ehrich, Dorothee; Thiemann, Gregory W.; Welker, Jeffrey Martin; Routti, Heli (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-19)
      Global changes are thought to affect most Arctic species, yet some populations are more at risk. Today, the Barents Sea ecoregion is suffering the strongest sea ice retreat ever measured; and these changes are suspected to modify food access and thus diet of several species. Biochemical diet tracers enable investigation of diet in species such as polar bears (Ursus maritimus). We examined ...

    • Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition 

      Lippold, Anna; Bourgeon, Sophie; Aars, Jon; Andersen, Magnus; Polder, Anuschka; Lyche, Jan Ludvig; Bytingsvik, Jenny; Jenssen, Bjørn Munro; Derocher, Andrew E.; Welker, Jeffrey Martin; Routti, Heli (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-14)
      Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, <i>p,p′</i>-DDE, HCB, β-HCH, oxychlordane, BDE-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears (<i>Ursus maritimus</i>) from the Barents Sea subpopulation were examined over 20 years (1997–2017). All 306 samples were collected in the spring (April). Both stable isotope values ...