Advanced stable isotope analyses of seabird feathers - ecological segregation and historical changes in trophic levels across four Antarctic and subantarctic seabird communities
Final Report Abstract
Nitrogen and carbon stable isotopes provide tools to investigate ecological segregation, prey choice and spatial distribution in seabirds. However, the interpretation of stable isotopes is frequently hampered by a lack of isotopic baseline data. In this study, two techniques proposed to overcome such shortages were tested: Compound-specific isotope analyses of amino acids (AA-CSIA) and the analysis of hydrogen stable isotope ratios (HSIA). Using two sympatric Antarctic storm-petrels as model species, we found that amino acid-specific stable isotope analyses were useful for estimating isotopic baselines and thus true trophic levels, whereas hydrogen isotopes were not. The present results suggest that differences in hydrogen ratios may be explained by these petrels moulting in different ocean zones. We then applied AA-CSIA to study interspecific differences, seasonal and historical changes in trophic levels of five seabird species, three penguins and two petrels, from a sub-Antarctic seabird community and foraging in temperate and polar waters. We found changes in trophic levels both among breeding stages and in comparison to historical samples. The methodological work in the present project now allows the application of these techniques to a variety of animal communities, not restricted to birds.
Publications
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(2017) Testing the usefulness of hydrogen and compound-specific stable isotope analyses in seabird feathers: a case study in two sympatric Antarctic storm-petrels. Marine Biology, 164, 192
Quillfeldt, P., Thorn, S., Richter, B., Nabte, M., Coria, N., Masello, J. F., Massaro, M., Neves, V.C. & Libertelli, M.
