Interactive effects of pollutants and climate on seabirds in Arctic Coastal ecosystems (ClimACTox)

Environmental pollutants can be harmful to wild animals. The extent of the harm depends on the levels, but it can worsen if animals are already facing difficulties, such as weather and climate phenomena that periodically lead to increased energy consumption or reduced food resources. Additionally, environmental pollutants are not evenly distributed worldwide. Some areas have higher levels and different compositions of pollutants than other areas. With few exceptions, Svalbard's birds are summer visitors that migrate south after the breeding season is over. Their destination will influence the quantity and types of pollutants they encounter. Their position in the food chain is also crucial, as pollutant levels increase higher up the food chain. By collecting feathers and blood samples, we obtain data on the types and levels of pollutants present in each individual. Additionally, by attaching a tracker to the leg ring, we can folow the birds' positions throughout the year. This allows us to examine how pollutants, weather/climate, and wintering areas impact the viability of three different seabird species in Svalbard and Northern Norway. The Common Eider feeds on shellfish and bottom-dwelling organisms, the Arctic Skua prefers fish, while the Great Skua is a predatory scavenger that also consume other birds. Consequently, these species represent different levels in the food chain, with the Great Skua at the top and the Common Eider at the bottom. We anticipate observing an increase in pollutant burden among species higher up in the food chain. Our aim is to understand how wintering area influences the levels and composition of pollutants. Through this approach, we may identify marine areas with more pollutants. We wish to illustrate which pollutants become more concentrated higher in the food chain. We also aim to determine whether the detrimental effects of pollutants are more pronounced during unfavorable weather conditions.

Rapid warming of oceans in recent decades combined with increased contaminant inputs and habitat disruption at higher latitudes (AMAP 2011) creates multiple pressures on Arctic and North temperate areas’ wildlife. Organisms are exposed to multiple stressors that may have additive or even synergistic effects on life-history traits. Climate is one of the most important factors affecting seabirds globally. Seabirds have been found to be less flexible in adapting their reproductive timing in response to increasing sea surface temperatures. This increased climate stress may be further emphasized by negative effects of pollutants. Once in the marine environment, organic pollutants and Hg (under its toxic and methylated form Me-Hg) enter the food chains where they bioaccumulate and biomagnify by increasing at higher trophic levels. Therefore, long-lived species at the top of the food chains, like seabirds, exhibit some of the highest wildlife concentrations of pollutants, making them particularly sensitive to the pollutants’ toxicity. The few available studies indicate that pollutants can have deleterious effects on adult survival or breeding success for the most contaminated species, and in concert with other stressors such a climate change, negative effects of pollutants may become increasingly severe. This project goal is to study long-term effects of seasonal spatial distributions and contamination with POPs and Hg of three species of seabirds, common eiders, arctic skuas and great skua, from high arctic Kongsfjorden (Svalbard, Norway) and mainland Norway. Theses species differ in their trophic ecology, life-history, and migratory movements, with wintering areas spanning from the southern hemisphere to Iceland and the coast of north Norway. Their migration expose individual seabirds to different concentrations of pollutants and a wide range of climatic zones and weather events.