| Summary: | Exposure to contaminants, such as Persistent Organic Pollutants (POPs), is currently considered a serious anthropogenic threat to marine predators and their food webs. Exposure to contaminants by marine wildlife is mainly related to their trophic ecology, distribution and movements. However, the contribution of these biological features to pollutant levels remains poorly understood in most marine predators, including seabirds. New methodologies, including dietary and geographic tracers, such as stable isotope analyses, and a wide array of devices to track movement at different spatial and temporal scales, can provide new light into this issue. Although stable isotope signatures in marine wildlife provide valuable information about their trophic ecology, isotopic baseline levels also show geographical differences. Therefore, to understand isotopic differences among separate wildlife populations we first need to evaluate the influence of spatial variability in stable isotope signatures. In the present dissertation, some ecological factors, mainly feeding ecology, breeding locality and movements, and their influence shaping the isotopic signatures and the contaminant burdens, were examined in most Procellariiformes breeding in the Northeast Atlantic Ocean and the Mediterranean Sea. In particular, the isotopic signatures of Carbon and Nitrogen (δ13C and δ15N) as well as burdens of polycyclic aromatic hydrocarbons (PAHs) and organochlorinated compounds (OCs), e.g., polychlorinated biphenyls (PCBs) and pesticides such as DDT, in seabirds were determined. In this study, firstly, we evaluate the relative influence of geographic origin, movements and trophic ecology in shaping stable isotope signatures and contaminant burdens in pelagic seabirds. Then, we show the spatial patterns in the isotopic signatures, OCs and PAHs that emerge among Mediterranean and northeast Atlantic seabirds and evaluate pollutant sources and the influence of long-range transport mechanisms on these basins. Secondly, we provide evidences that ...
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