Variability in tissue-specific trophic discrimination factors (∆13C and ∆15N) between Antarctic krill Euphausia superba and free-ranging Pygoscelis penguins

• Published in: Polar Biology
• Main Authors: Ceia, Filipe, Cherel, Yves, Seco, José, Barbosa, Andrés, Chipev, Nesho, Xavier, José
• Other Authors: Marine and Environmental Sciences Centre (MARE UC), Universidade de Coimbra Coimbra, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), CESAM & Department of Chemistry, Universidade de Aveiro, Departamento de Ecología Evolutiva (Museo Nacional de Ciencias Naturales), Museo Nacional de Ciencias Naturales Madrid (MNCN), Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC)-Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC), Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences (BAS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Carbon; Nitrogen; Stable isotopes; Chinstrap; Gentoo; Isotopic variability; [SDE]Environmental Sciences; Antarctic; Livingston Island; Antarc*; Antarctic Krill; Antarctica; Euphausia superba; Polar Biology; Pygoscelis antarctica
• Online Access: https://hal.science/hal-03292361; https://doi.org/10.1007/s00300-021-02889-2

International audience For top consumers in marine environments, trophic discrimination factors (Δ13C and Δ15N) between food and consumers’tissues are expected to be similar among related species. However, few studies conducted in the laboratory indicate a largevariability among species, which should be potentially higher in free-ranging animals. Here, we test for differences in tissuespecificΔ13C and Δ15N values of two wild penguin species (Chinstrap Pygoscelis antarctica and Gentoo P. papua) breedingin sympatry at Livingston Island, Antarctica. A total of 41 adults and 28 chicks, and food items comprised exclusively byAntarctic krill (Euphausia superba, n = 22) in Chinstraps and almost exclusively in Gentoos, were sampled for stable isotopeanalyses. Overall, Δ13C values varied between -1.8 and 4.0 ‰ and Δ15N values ranged from 1.2 to 6.1 ‰, and thesediffered between species, tissues and age-classes. Δ13C in adult penguins differed between species for feather and blood.Species-specific differences in Δ13C and Δ15N were seen in chick nail and muscle, while only Δ13C values differed betweenspecies in feathers. Our results show that trophic discrimination factors can differ substantially between closely related speciesconsuming similar prey, especially in Δ13C value. Variation in Δ13C was driven by species, tissue and age-class, whilevariation in Δ15N was mostly driven by tissue type. Trophic discrimination factors may be associated to physiological and/or stress factors which may fluctuate in the wild, and this was particularly evident on chicks. This study highlights the useof diet-specialised species for the determination of trophic discrimination factors in the wild.