Ecological consequences of environmental contaminants in a marine sentinel species: A multiple stressor approach

The marine environment is a sink and transport route for pollution, and marine top predators are characterized by relatively high levels of biomagnifying organic contaminants and mercury. As such, they represent good biological models to assess the impact of pollutants on ecosystem health. The project has explored potential impacts of pollutant exposure in a sentinel top predator : the white-tailed eagle, within a multi-stressor framework. The project has investigated the magnitude and composition of legacy and emerging contaminants, and identify biogeochemical proxies for underlying dietary pathways in different regions of the white-tailed eagle distribution. Moreover, we aimed to identify consistent biomarkers of stress in relation to pollutant exposure in different white-tailed eagle subpopulations. Finally, we have combined long-term population data on reproduction and density with multi-stressor data such as contaminant exposure, variability in dietary ecology, climate, and stress biomarkers, in central geographical white-tailed eagle subpopulations. Hence, statistical analyses of the above empirical data are integrated with theoretical models, where impacts at the individual level will be translated into wider population-level effects. This enables an approach where we can explore potential ecological effects of contaminants in a hierarchical fashion going from physiology through individual life-histories to population dynamics.

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The marine environment functions as a sink and transport route for contaminants, and marine top predators are characterised by relatively high levels of both emerging and legacy organohalogenated contaminants and mercury. As such, they represent good biological models to assess the impact of such environmentally persistent pollutants (EPPs) on ecosystem health. The aim of this project is to explore the role of EPP exposure within a multi-stressor framework that is hypothesised to cause ecologically relevant effects in a sentinel top predator in the Norwegian marine fauna: the white-tailed eagle (WTE: Haliaeetus albicilla). The project is divided into three interconnected work packages (WPs). WP1 will investigate for the first time the magnitude and composition of legacy and emerging EPP exposure, and identify biogeochemical proxies for underlying dietary pathways in different regions of the WTE distribution. WP2 will identify consistent biomarkers of stress in relation to EPP exposure in the different WTE subpopulations addressed in WP1. WP3 will combine long-term (1970s to present day) population data, i.e. reproduction and density, with multi-stressor data, i.e. EPP exposure, variability in dietary ecology and climate, and stress biomarkers, in central geographical WTE subpopulations. More importantly, statistical analyses of the above empirical data will be integrated with theoretical modelling exercises, where impacts at the individual level (e.g. reproduction and survival) will be translated into wider population-level effects. This opens up for an approach where we can explore potential ecological effects of EPPs in an hierarchical fashion going from physiology through individual life-histories (with an explicit link to demography) to spatiotemporal population-level dynamics. In the end, this project will provide valuable tools that will advance the ecotoxicology and conservation of WTE and other raptor populations.