Feathers as a Tool to Assess Mercury Contamination in Gentoo Penguins: Variations at the Individual Level.
Feathers have been widely used to assess mercury contamination in birds as they reflect metal concentrations accumulated between successive moult periods: they are also easy to sample and have minimum impact on the study birds. Moult is considered the major pathway for mercury excretion in seabirds. Penguins are widely believed to undergo a complete, annual moult during which they do not feed. As penguins lose all their feathers, they are expected to have a low individual-variability in feather mercury concentration as all feathers are formed simultaneously from the same somatic reserves. This assumption is central to penguin studies that use feathers to examine the annual or among-individual variation in mercury concentrations in penguins. To test this assumption, we measured the mercury concentrations in 3-5 body feathers of 52 gentoo penguins (Pygoscelis papua) breeding at Bird Island, South Georgia (54°S 38°W). Twenty-five percent of the penguins studied showed substantial within-individual variation in the amount of mercury in their feathers (Coefficient of Variation: 34.7-96.7%). This variation may be caused by differences in moult patterns among individuals within the population leading to different interpretations in the overall population. Further investigation is now needed to fully understand individual variation in penguins' moult.
Centre of Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
Sara
S
Pedro
MARE-Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal; British Antarctic Survey, Cambridge, United Kingdom.
José C
JC
Xavier
Centre of Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
Sílvia
S
Tavares
British Antarctic Survey, Cambridge, United Kingdom.
Phil N
PN
Trathan
British Antarctic Survey, Cambridge, United Kingdom.
Norman
N
Ratcliffe
MARE-Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
Vitor H
VH
Paiva
Cardiff School of Biosciences, Cardiff University, Cardiff, South Glamorgan, Wales, United Kingdom.
Renata
R
Medeiros
Centre for Environmental and Marine Studies, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
Eduarda
E
Pereira
Centre of Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
Miguel A
MA
Pardal
D000818:Animals; D004784:Environmental Monitoring; D005241:Feathers / Q000737:chemistry / Q000166:cytology*; D008628:Mercury / Q000302:isolation & purification* / Q000633:toxicity; D046429:Spheniscidae
D008628:Mercury