Affiliations 

  • 1 Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China; Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia. Electronic address: nyukling@umt.edu.my
  • 2 Aarhus University, Department of Environmental Science, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: martin.hansen@envs.au.dk
  • 3 Aarhus University, Department of Bioscience, Grenåvej 14, DK-8410 Rønde, Denmark. Electronic address: oth@bios.au.dk
  • 4 Aarhus University, Department of Bioscience, Grenåvej 14, DK-8410 Rønde, Denmark. Electronic address: tk@bios.au.dk
  • 5 Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: rst@bios.au.dk
  • 6 Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
  • 7 Christiansø Scientific Field Station, Christiansø 97, DK-3760 Gudhjem, Denmark
  • 8 Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China
  • 9 Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP) & Institute of Tropical Biodiversity and Sustainable Development (Bio-D Tropika), Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia. Electronic address: lam@umt.edu.my
  • 10 University of Copenhagen, Faculty of Health and Medical Sciences, Department of Veterinary Clinical Sciences, Dyrlægevej 16, DK-1870 Frederiksberg C, Denmark. Electronic address: akrk@sund.ku.dk
  • 11 University of Copenhagen, Faculty of Health and Medical Sciences, Department of Veterinary Clinical Sciences, Dyrlægevej 16, DK-1870 Frederiksberg C, Denmark. Electronic address: emilie.ranberg@sund.ku.dk
  • 12 Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: js@bios.au.dk
  • 13 Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: ffr@bios.au.dk
  • 14 Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: rdi@bios.au.dk
  • 15 Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark; Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou 450002, China. Electronic address: cs@bios.au.dk
Environ Int, 2020 09;142:105866.
PMID: 32590281 DOI: 10.1016/j.envint.2020.105866

Abstract

The Baltic/Wadden Sea Flyway of common eiders has declined over the past three decades. Multiple factors such as contaminant exposure, global warming, hunting, white-tailed eagle predation, decreased agricultural eutrophication and infectious diseases have been suggested to explain the decline. We collected information on body mass, mercury (Hg) concentration, biochemistry and untargeted metabolomics of incubating birds in two colonies in the Danish Straits (Hov Røn, n = 100; Agersø, n = 29) and in one colony in the Baltic proper (Christiansø, n = 23) to look into their metabolisms and energy balance. Body mass was available from early and late incubation for Hov Røn and Christiansø, showing a significant decline (25-30%) in both colonies with late body mass at Christiansø being the lowest. Whole blood concentrations of total mercury Hg were significantly higher in birds at Christiansø in the east compared to Hov Røn in the west. All birds in the three colonies had Hg concentrations in the range of ≤1.0 μg/g ww, which indicates that the risk of effects on reproduction is in the no to low risk category for wild birds. Among the biochemical measures, glucose, fructosamine, amylase, albumin and protein decreased significantly from early to late incubation at Hov Røn and Christiansø, reflecting long-term fastening as supported by the decline in body mass. Untargeted metabolomics performed on Christiansø eiders revealed presence of 8,433 plasma metabolites. Of these, 3,179 metabolites changed significantly (log2-fold change ≥1, p ≤ 0.05) from the early to late incubation. For example, smaller peptides and vitamin B2 (riboflavin) were significantly down-regulated while 11-deoxycorticosterone and palmitoylcarnitine were significantly upregulated. These results show that cumulative stress including fasting during incubation affect the eiders' biochemical profile and energy metabolism and that this may be most pronounced for the Christiansø colony in the Baltic proper. This amplify the events of temperature increases and food web changes caused by global warming that eventually accelerate the loss in body weight. Future studies should examine the relationship between body condition, temperature and reproductive outcomes and include mapping of food web contaminant, energy and nutrient content to better understand, manage and conserve the populations.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.