Penguins as bioindicators of mercury contamination in the Southern Ocean: Birds from the Kerguelen Islands as a case study

• Main Authors: Alice Carravieri, Paco Bustamante, ⁎⁎ Carine Churlaud, Yves Cherel
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Indian; Kerguelen; Kerguelen Islands; Southern Ocean; Antarc*; Gentoo penguin; Rockhopper penguin
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1052.2487; http://www.cebc.cnrs.fr/publipdf/2013/CSTE454_2013.pdf

• Hg contamination was evaluated in 4 species of penguins at the Kerguelen Islands. • Adults displayed significantly higher Hg levels than chicks in all species. • Species and feeding habits (δ15N) were major determinants of Hg levels. • Dietary specialisation was essential in explaining Hg levels in gentoo penguins. • Penguins are reliable bioindicators of Hg contamination in the Southern Ocean. a b s t r a c t a r t i c l e i n f o Seabirds have been used extensively as bioindicators of mercury (Hg) contamination in the marine environment, although information on flightless species like penguins remains limited. In order to assess the use of penguins as bioindicators of Hg contamination in subantarctic and Antarctic marine ecosystems, Hg concentrations were evaluated in the feathers of the four species that breed on the Kerguelen Islands in the southern Indian Ocean. Compared to other seabirds, adult Kerguelen penguins had low to moderate feather Hg concentrations, with an average ranging from 1.96 ± 0.41 μg g −1 dry weight in the southern rockhopper penguin to 5.85 ± 3.00 μg g −1 dry weight in the gentoo penguin. The species was a major determinant of Hg contamination, with feather Hg concentrations being lower in the oceanic species (king and crested penguins) than in the coastal one (gentoo penguin). In all species however, feather Hg concentrations were higher in adults than in chicks, reflecting the different periods of Hg bioaccumulation in the internal tissues of the two age classes. The relationship between adult penguin trophic ecology and Hg burdens was investigated using stable isotopes. Feeding habits (reflected by δ 15 N values) had a greater effect on adult feather Hg concentrations when compared to foraging habitats (reflected by δ 13 C values), indicating Hg biomagnification in Kerguelen neritic and oceanic waters. Dietary preferences were crucial in explaining individual feather Hg concentrations, as highlighted by intra-specific variation in Hg levels of gentoo penguins sampled at two ...