Seabirds reveal mercury distribution across the North Atlantic.

Mercury (Hg) is a heterogeneously distributed toxicant affecting wildlife and human health. Yet, the spatial distribution of Hg remains poorly documented, especially in food webs, even though this knowledge is essential to assess large-scale risk of toxicity for the biota and human populations. Here, we used seabirds to assess, at an unprecedented population and geographic magnitude and high resolution, the spatial distribution of Hg in North Atlantic marine food webs. To this end, we combined tracking data of 837 seabirds from seven different species and 27 breeding colonies located across the North Atlantic and Atlantic Arctic together with Hg analyses in feathers representing individual seabird contamination based on their winter distribution. Our results highlight an east-west gradient in Hg concentrations with hot spots around southern Greenland and the east coast of Canada and a cold spot in the Barents and Kara Seas. We hypothesize that those gradients are influenced by eastern (Norwegian Atlantic Current and West Spitsbergen Current) and western (East Greenland Current) oceanic currents and melting of the Greenland Ice Sheet. By tracking spatial Hg contamination in marine ecosystems and through the identification of areas at risk of Hg toxicity, this study provides essential knowledge for international decisions about where the regulation of pollutants should be prioritized.

An ecologically sound and participatory monitoring network for pan-Arctic seabirds.

In a warming Arctic, circumpolar long-term monitoring programs are key to advancing ecological knowledge and informing environmental policies. Calls for better involvement of Arctic peoples in all stages of the monitoring process are widespread, although such transformation of Arctic science is still in its infancy. Seabirds stand out as ecological sentinels of environmental changes, and priority has been given to implement the Circumpolar Seabird Monitoring Plan (CSMP). We assessed the representativeness of a pan-Arctic seabird monitoring network focused on the black-legged kittiwake (Rissa tridactyla) by comparing the distribution of environmental variables for all known versus monitored colonies. We found that with respect to its spatiotemporal coverage, this monitoring network does not fully embrace current and future environmental gradients. To improve the current scheme, we designed a method to identify colonies whose inclusion in the monitoring network will improve its ecological representativeness, limit logistical constraints, and improve involvement of Arctic peoples. We thereby highlight that inclusion of study sites in the Bering Sea, Siberia, western Russia, northern Norway, and southeastern Greenland could improve the current monitoring network and that their proximity to local populations might allow increased involvement of local communities. Our framework can be applied to improve existing monitoring networks in other ecoregions and sociological contexts.

Una red de monitoreo participativa y ecológica para las aves marinas del Ártico Resumen En un Ártico cada vez más cálido, los programas circumpolares de monitoreo a largo plazo son importantes para potenciar el conocimiento ecológico e informar las políticas ambientales. Existe un llamado generalizado para involucrar de mejor manera a los pueblos árticos en el proceso de monitoreo, aunque dicha transformación de la ciencia ártica todavía está en desarrollo. Las aves marinas resaltan como centinelas del cambio ambiental y se ha priorizado implementar el Plan Circumpolar de Monitoreo de Aves Marinas (CSMP). Comparamos la distribución de las variables ambientales de todas las colonias conocidas de la gaviota tridáctila (Rissa tridactyla) contra las colonias monitoreadas para evaluar la representación de una red pan­ártica de monitoreo enfocada en esta especie. Encontramos que esta red de monitoreo no considera del todo los gradientes ambientales actuales y futuros con respecto a la cobertura espaciotemporal. Para mejorar el esquema actual, diseñamos un método para identificar las colonias cuya inclusión en la red de monitoreo mejorará su representación ecológica, limitará las restricciones logísticas e incrementará la participación de los pueblos árticos. Por lo tanto, resaltamos que la inclusión de los sitios de estudio en el Mar de Bering, Siberia, Rusia occidental, el norte de Noruega y el sureste de Groenlandia mejorarían la red actual de monitoreo. También destacamos que la proximidad de los sitios de estudio con las poblaciones locales podría permitir una mayor participación de estas. Nuestro marco puede aplicarse para mejorar las redes de monitoreo existentes en otros contextos socioecológicos y ecoregiones.