Polar atmosphere-ice-ocean Interactions : Impact on Climate and Ecology

Séminaire de Manuel Dall´Osto (Institute of Marine Sciences), mardi 6 mars à 10h en salle 105 OSUG-B

Titre : Polar atmosphere-ice-ocean Interactions : Impact on Climate and Ecology

Résumé : Climate warming affects the development and distribution of sea ice, but at present the evidence of polar ecosystem feedbacks on climate through changes in the atmosphere is sparse. In this presentation, I will show main results carried out at the ICM-CSIC Barcelona (Spain) with interdisciplinary collaborations from UK, USA, Ireland, Spain, Sweden and Korea. Both Polar regions are considered. (1) By means of synergistic atmospheric and oceanic measurements in the Southern Ocean near Antarctica, we present evidence that the microbiota of sea ice and sea ice-influenced ocean are a previously unknown significant source of atmospheric organic nitrogen, including low molecular weight alkyl-amines. Given the keystone role of nitrogen compounds in aerosol formation, growth and neutralization, our findings call for greater diversity in modeling efforts linking the marine ecosystem to aerosol-mediated climate effects in the Southern Ocean. (2) Atmospheric new particle formation and growth significantly influences climate by supplying new seeds for cloud condensation and brightness. Currently, there is a lack of understanding of whether and how marine biota emissions affect aerosol-cloud-climate interactions in the Arctic. Here, the aerosol population was categorised via cluster analysis of aerosol size distributions taken at Mt Zeppelin (Svalbard) during a 11 year record (2000-2010) and at Station Nord (Greenland) during a 7 year period (2010-2016). Overall results are discussed (Figure 1). Briefly, air mass trajectory analysis and atmospheric nitrogen and sulphur tracers link these frequent nucleation events to biogenic precursors released by open water and melting sea ice regions. The occurrence of such events across a full decade was anti-correlated with sea ice extent. During the last part of the presentation I aim also to present possible collaborations on sea ice-ocean-atmosphere biogeochemistry.

Par : Manuel Dall´Osto, chercheur à l’Institut des Sciences Maritimes (ICM-CSIC), Spanish National Research Council (Barcelona, Spain)
Email : dallosto icm.csic.es
Animation : Aurélien Dommergue

PNG Figure 1. Schematic illustrations of the seasonal cycle of sea-ice, microbiota, sea-to-air emissions and ultrafine aerosols in the Arctic. © Dall’Osto, 2018.