Long-term effects of environmental changes on ArctiC seabirds: effeCts of seasonal distribUtion and contaMination on popULATION dynamics

Emissions of pollutants in the Arctic are low but high concentrations of Persistent Organic Pollutants (POPs) and mercury (Hg) have been measured in Arctic seabirds during their breeding season. Pollutants are transported over large distances from southern region to the Arctic through rivers, oceanic and atmospheric currents, where they are deposited on sea ice and glaciers. Melting of sea ice and glaciers has been increasing over time with climate change, which also releases contaminants in the Arctic. Seabirds are contaminated by pollutants during their breeding season in the Arctic, with negative effects on reproduction or behavior. As migratory species, seabirds do not stay in the Arctic and winter in southern oceans, where they get more contaminated than during summer. The long-term effects of both summer and winter contamination on seabird survival and reproduction is still understudied. We aim at filling this knowledge gap to better manage the risk of long-term contamination of pollutants on sensitive species of Arctic birds. Our work will be important for bird conservation. We will study three species of seabirds (common eiders (Somateria mollissima), Arctic skua (Stercorarius parasiticus) and great skuas (S. skua) that breed in Kongsfjorden in Svalbard, but feed on different preys and winter in different regions that affects their exposure to pollutants. In Kongsfjorden, they have been monitored for pollutants for 14-16 years and two years of additional fieldwork are planned. Contaminants will be analyzed in collaboration with the Littoral, Environment and Society institute (La Rochelle University, France), the ARCTOX network and NILU (Norway). Wintering grounds will be determined in collaboration with the SEATRACK program. ACCUMULATION is a project that combine modern tools in bird migration, ecotoxicology (ecology, pollutants), and population demography (survival, reproduction) in relation to climate change.

The Arctic has become a sink for pollutants like Persistent Organic Pollutants (POPs) and mercury (Hg), exacerbated by climate change. As POPs and Hg increase in individuals (i.e., bioaccumulation) and into marine food chains (i.e. biomagnification), top-predators like seabirds present some of the highest wildlife concentrations, making them particularly sensitive to the pollutants toxicity. The long-term effects of contaminants on Arctic seabird population dynamics are still scarcely explored but the few studies found that those pollutants had deleterious effects on adult survival or breeding success for the most contaminated species. However, those studied focused on breeding period contamination only, that just represent a part of their annual cycle. With this project, we aim to study the influence of seasonal (i.e., breeding and non-breeding period) and spatial variations in distribution and contamination by POPs and Hg on population dynamics of Arctic seabirds. More specifically, we will study the influence on the population survival of 1/ long-term contaminant exposure during breeding periods and the relationship with climate change, 2/ non-breeding distribution and long-term contaminant exposure. To do so, we will study common eiders (Somateria mollissima), Arctic- (Stercorarius parasiticus) and great skuas (S. skua) breeding sympatrically at Kongsfjorden (Svalbard), where they have been monitored for ~17 years. Ultimately, this research will be essential to better acknowledge the risk of long-term and acute contamination to pollutants on already sensitive Arctic seabird species. Dr Albert will 1/ lead two additional field seasons to collect blood and feathers samples, and deploy geotracking devices 2/ do the laboratory analyses and 3/ perform population dynamics analyses. We will work with an interdisciplinarity team to investigate for the first time spatial ecology, ecotoxicology, climate change and population dynamics.