1 23 Polar Biology ISSN 0722-4060 Polar Biol DOI 10.1007/s00300-015-1697-9 Mercury accumulation in gentoo penguins Pygoscelis papua: spatial, temporal and sexual intraspecific variations Sara Pedro, José C. Xavier, Sílvia Tavares, Phil N. Trathan, Norman Ratcliffe, Vitor H. Paiva, Renata Medeiros, Rui P. Vieira, et al.