Factors controlling atmospheric DMS and its oxidation products (MSA and nssSO 4 2- ) in the aerosol at Terra Nova Bay, Antarctica

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Becagli, Silvia, Barbaro, Elena, Bonamano, Simone, Caiazzo, Laura, Di Sarra, Alcide, Feltracco, Matteo, Grigioni, Paolo, Heintzenberg, Jost, Lazzara, Luigi, Legrand, Michel, Madonia, Alice, Marcelli, Marco, Melillo, Chiara, Meloni, Daniela, Nuccio, Caterina, Pace, Giandomenico, Park, Ki-Tae, Preunkert, Suzanne, Severi, Mirko, Vecchiato, Marco, Zangrando, Roberta, Traversi, Rita
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU]Sciences of the Universe [physics]; Antarc*; Antarctic; Antarctica; Sea ice
• Online Access: https://insu.hal.science/insu-03839375; https://insu.hal.science/insu-03839375/document; https://insu.hal.science/insu-03839375/file/acp-22-9245-2022.pdf; https://doi.org/10.5194/acp-22-9245-2022

International audience This paper presents the results of simultaneous high time-resolution measurements of biogenic aerosol (methane sulfonic acid (MSA), non-sea salt sulfate nssSO 4 2- ) with its gaseous precursor dimethylsulfide (DMS), performed at the Italian coastal base Mario Zucchelli Station (MZS) in Terra Nova Bay (MZS) during two summer campaigns (2018-2019 and 2019-2020). Data on atmospheric DMS concentration are scarce, especially in Antarctica. The DMS maximum at MZS occurs in December, one month earlier than at other Antarctic stations. The maximum of DMS concentration is connected with the phytoplanktonic senescent phase following the bloom of Phaeocystis antarctica that occurs in the polynya when sea ice opens up. The second plankton bloom occurs in January and, despite the high dimethylsufoniopropionate (DMSP) concentration in seawater, atmospheric DMS remains low, probably due to its fast biological turnover in seawater in this period. The intensity and timing of the DMS evolution during the two years suggest that only the portion of the polynya close to the sampling site produces a discernible effect on the measured DMS. The closeness to the DMS source area and the occurrence of air masses containing DMS and freshly formed oxidation products allow us to study the kinetic of biogenic aerosol formation and the reliable derivation of the branch ratio between MSA and nssSO 4 2- from DMS oxidation that is estimated to be 0.84±0.06. Conversely, for aged air masses with low DMS content, an enrichment of nssSO 4 2- with respect to MSA, is observed. We estimate that the mean contribution of freshly formed biogenic aerosol to PM 10 is 17 % with a maximum of 56 %. The high contribution of biogenic aerosol to the total PM 10 mass in summer in this area highlights the dominant role of the polynya on biogenic aerosol formation. Finally, due to the regional and year-to-year variability of DMS and related biogenic aerosol formation, we stress the need for long-term measurements of seawater and atmospheric ...