Evidence of atmospheric nanoparticle formation from emissions of marine microorganisms

K. Sellegri (1) , J. Pey (2) , C. Rose (1) , A. Culot (3) , H.L. Dewitt (2) , S. Mas (4) , A.N. Schwier (1) , B. Temime-Roussel (2) , B. Charrière (5) , A. Saiz-Lopez (6) , A. S. Mahajan (7) , D. Parin (4) , A. Kukui (8) , R. Sempéré (9) , B. d'Anna (10) , Nicolas Marchand (2)

1 LaMP - Laboratoire de météorologie physique
2 LCE - Laboratoire Chimie de l'environnement
3 LACy - Laboratoire de l'Atmosphère et des Cyclones
4 OSU OREME - Observatoire de REcherche Méditerranéen de l'Environnement
5 CEFREM - Centre de Formation et de Recherche sur les Environnements Méditérranéens
6 Laboratory for Atmospheric and Climate Science
7 IITM - Indian Institute of Tropical Meteorology
8 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
9 LMGEM - Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines
10 CARE - IRCELYON-Catalytic and Atmospheric Reactivity for the Environment

Earth, as a whole, can be considered as a living organism emitting gases and particles into its atmosphere, in order to regulate its own temperature. In particular, oceans may respond to climate change by emitting particles that ultimately will influence cloud coverage. At the global scale, a large fraction of the aerosol number concentration is formed by nucleation of gas-phase species, but this process has never been directly observed above oceans. Here we present, using semicontrolled seawater-air enclosures, evidence that nucleation may occur from marine biological emissions in the atmosphere of the open ocean. We identify iodine-containing species as major precursors for new particle clusters’ formation, while questioning the role of the commonly accepted dimethyl sulfide oxidation products, in forming new particle clusters in the region investigated and within a time scale on the order of an hour. We further show that amines would sustain the new particle formation process by growing the new clusters to larger sizes. Our results suggest that iodine-containing species and amines are correlated to different biological tracers. These observations, if generalized, would call for a substantial change of modeling approaches of the sea-to-air interactions.

Keywords: ChArMEx

Domains: Sciences of the Universe [physics]; Ocean, Atmosphere

K. Sellegri, J. Pey, C. Rose, A. Culot, H.L. Dewitt, et al.. Evidence of atmospheric nanoparticle formation from emissions of marine microorganisms. Geophysical Research Letters, 2016, 43 (12), pp.6596-6603. ⟨10.1002/2016GL069389⟩. ⟨insu-01344534⟩