Comparative analysis of trace element deposition in adult Gentoo penguin feathers across different Antarctic...

Segmental analysis of the feather provides a chronological and physiological resolution that whole-feather measurements lack. Despite their crucial ecological importance, trace element (TEs) accumulation along the feathers in penguins from Antarctica has remained understudied. This study utilized feathers as a non-destructive bioindicator to assess the concentrations of twenty-four TEs (via ICP-MS) and stable isotopes (δ¹⁵N, δ¹³C, and δ³⁴S) in adult Gentoo penguins (Pygoscelis papua). Samples were selected from four sites across the Antarctic Peninsula area (Kopaitic Island, Ardley Island, Base O'Higgins, and Gonzalez Videla Station), during the austral summer of 2011. About 300 feathers were collected across individuals within a site, and then the samples were divided into three groups (100 feathers each) for pooling; then feathers were cut into three distinct segments (A: calamus, B: middle, and C: tip) to achieve a pooled mass of 0.33 g per segment. To evaluate deposition patterns, measurements were conducted along three distinct sections of each feather. A greater accumulation of Al, Sr, Ba, Mn, Ag, As, Cd, Cr, Rb, V, Tl, and U was observed in the tips relative to the calamus at all locations. The highest TE concentrations are in feather's tip from O'Higgins Base (with human activity), whereas the lowest levels occurred at Ardley Island and Gonzalez Videla Station, both of which poses low human presence. Isotopic data showed that these adult specimens are generalist predators, with diets shifting according to local prey availability. TE levels may pose significant health risks to penguins, highlighting a need for further research into the long-term toxicological impacts on the population of this emblematic seabird.