Demographical effects of toxic contamination on Arctic seabirds

Descrizione del progetto

Gli effetti del mercurio sulla piccola alca dell’Artico

Dall’inizio della rivoluzione industriale i livelli di mercurio (Hg) negli strati superiori dell’oceano sono triplicati. Il mercurio presente in fiumi, laghi e oceani costituisce il rischio maggiore. Una volta convertito in una sostanza tossica da esso derivata chiamata metilmercurio, viene assorbito dagli animali e risale la filiera alimentare fino a raggiungere gli esseri umani. Il selenio (Se) è in grado di fornire una protezione efficace dalla tossicità legata all’Hg. Il progetto DeToxSea, finanziato dall’UE, valuterà l’interazione tra Se e Hg concentrando l’attenzione sulla piccola alca, un uccello nidificante che vive nell’Artico. Il progetto verificherà l’ipotesi secondo cui le concentrazioni di Se/Hg influenzano la capacità riproduttiva di questo animale. I risultati chiariranno gli effetti a livello demografico della contaminazione tossica di Se/Hg nella fauna selvatica dell’Artico.

Obiettivo

Mercury (Hg) concentrations in the oceans have tripled in the last centuries, even in remote areas such as the Arctic. Hg is bioaccumulated in food webs and can produce toxic effects affecting breeding and survival probabilities in wildlife. Selenium (Se) has been proved to have a protective effect against Hg toxicity, but no long-term studies have been carried out to evaluate reproductive output and population dynamics in relation to Se or the interaction Se-Hg. Using as a population model the most abundant breeding bird in the Arctic, the little auk (Alle alle), I aim to 1) evaluate the temporal trends of Se/Hg and on which intrinsic/extrinsic factors they depend on; 2) investigate if Se/Hg concentrations affect the reproductive output of little auks (i.e. at the individual level); and 3) evaluate the effects of Se/Hg at the population levels in the context of climate change (i.e. considering environmental conditions). To do so, I will use data of 15 years of monitoring on little auks from west Greenland (Kape Høegh). I will analyse pollutants on blood samples at the host laboratory, and I will perform different statistical approaches to investigate our objectives. In particular, we will look for functional relationships to evaluate pollutants temporal/environmental trends and their toxic effects on the reproductive output of little auks; and demographic models (multistate mark-recapture models and matrix population models) to evaluate the projected population growth rate and its sensitivity to Hg/Se and environmental conditions. This research program will gather knowledge from a large interdisciplinary team, with expertise in ecotoxicology and demography. We anticipate major public interest for the results of DeToxSea: the unique long-term study about demographic effects of Se/Hg toxic contamination in Arctic wildlife, that will give light to one of the Challenges of Horizon 2020 about Climate Action, Environment, Resource Efficiency and Raw Materials.