Shipborne measurements of Antarctic submicron organic aerosols: an NMR perspective linking multiple sources and bioregions

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Decesari, S., Paglione, Marco, Rinaldi, Matteo, Dall'Osto, Manuel, Simó, Rafel, Zanca, Nicola, Volpi, Francesca, Facchini, M.C., Hoffmann, Thorsten, Götz, Sven, Kampf, Johannes, O'Dowd, Colin D., Ceburnis, Darius, Ovadnevaite, Jurgita, Tagliavini, Emilio
• Other Authors: European Commission, Ministerio de Economía y Competitividad (España), Consiglio Nazionale delle Ricerche, Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: European Geosciences Union 2020
• Subjects: Antarctic; Antarc*; Antarctica; Sea ice
• Online Access: http://hdl.handle.net/10261/211369; https://doi.org/10.5194/acp-20-4193-2020; https://doi.org/10.13039/501100003329; https://doi.org/10.13039/501100000780; https://doi.org/10.13039/501100004462; https://doi.org/10.13039/501100011033

Special issue Marine organic matter: from biological production in the ocean toorganic aerosol particles and marine clouds (ACP/OS inter-journalSI).-- 15 pages, 8 figures, 1 table, supplement https://doi.org/10.5194/acp-20-4193-2020 The concentrations of submicron aerosol particles in maritime regions around Antarctica are influenced by the extent of sea ice. This effect is two ways: on one side, sea ice regulates the production of particles by sea spray (primary aerosols); on the other side, it hosts complex communities of organisms emitting precursors for secondary particles. Past studies documenting the chemical composition of fine aerosols in Antarctica indicate various potential primary and secondary sources active in coastal areas, in offshore marine regions, and in the sea ice itself. In particular, beside the well-known sources of organic and sulfur material originating from the oxidation of dimethylsulfide (DMS) produced by microalgae, recent findings obtained during the 2015 PEGASO cruise suggest that nitrogen-containing organic compounds are also produced by the microbiota colonizing the marginal ice zone. To complement the aerosol source apportionment performed using online mass spectrometric techniques, here we discuss the outcomes of offline spectroscopic analysis performed by nuclear magnetic resonance (NMR) spectroscopy. In this study we (i) present the composition of ambient aerosols over open-ocean waters across bioregions, and compare it to the composition of (ii) seawater samples and (iii) bubble-bursting aerosols produced in a sea-spray chamber onboard the ship. Our results show that the process of aerosolization in the tank enriches primary marine particles with lipids and sugars while depleting them of free amino acids, providing an explanation for why amino acids occurred only at trace concentrations in the marine aerosol samples analyzed. The analysis of water-soluble organic carbon (WSOC) in ambient submicron aerosol samples shows distinct NMR fingerprints for three bioregions: (1) ...