Characteristics of methanesulfonic acid, non-sea-salt sulfate and organic carbon aerosols over the Amundsen Sea, Antarctica

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Jung, Jinyoung, Hong, Sang-Bum, Chen, Meilian, Hur, Jin, Jiao, Liping, Lee, Youngju, Park, Keyhong, Hahm, Doshik, Choi, Jung-Ok, Yang, Eun Jin, Park, Jisoo, Kim, Tae-Wan, Lee, SangHoon
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: article; Verlagsveröffentlichung; Amundsen Sea; Austral; Southern Ocean; Antarc*; Antarctica
• Online Access: https://doi.org/10.5194/acp-20-5405-2020; https://noa.gwlb.de/receive/cop_mods_00051460; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00051116/acp-20-5405-2020.pdf; https://acp.copernicus.org/articles/20/5405/2020/acp-20-5405-2020.pdf

To investigate the characteristics of particulate methanesulfonic acid (MSA(p)), non-sea-salt sulfate (nss SO42-) and organic carbon (OC) aerosols, aerosol and seawater samples were collected over the Southern Ocean (43–70∘ S) and the Amundsen Sea (70–75∘ S) during the ANA06B cruise conducted in the austral summer of 2016 aboard the Korean icebreaker IBR/V Araon. Over the Southern Ocean, the atmospheric MSA(p) concentration was low (0.10±0.002 µg m−3), whereas its concentration increased sharply up to 0.57 µg m−3 in the Amundsen Sea where Phaeocystis antarctica (P. antarctica), a producer of dimethylsulfide (DMS), was the dominant phytoplankton species. Unlike MSA(p), the mean nss SO42- concentration in the Amundsen Sea was comparable to that in the Southern Ocean. Water-soluble organic carbon (WSOC) concentrations over the Southern Ocean and the Amundsen Sea varied from 0.048 to 0.16 and 0.070 to 0.18 µgC m−3, with averages of 0.087±0.038 and 0.097±0.038 µgC m−3, respectively. For water-insoluble organic carbon (WIOC), its mean concentrations over the Southern Ocean and the Amundsen Sea were 0.25±0.13 and 0.26±0.10 µgC m−3, varying from 0.083 to 0.49 and 0.12 to 0.38 µgC m−3, respectively. WIOC was the dominant organic carbon species in both the Southern Ocean and the Amundsen Sea, accounting for 73 %–75 % of the total aerosol organic carbon. WSOC/Na+ and WIOC/Na+ ratios in the fine-mode aerosol particles were higher, especially in the Amundsen Sea where biological productivity was much higher than the Southern Ocean. The fluorescence properties of water-soluble organic aerosols investigated using a fluorescence excitation–emission matrix coupled with parallel factor analysis (EEM–PARAFAC) revealed that protein-like components were dominant in our marine aerosol samples, representing 69 %–91 % of the total intensity. Protein-like components also showed a significant positive relationship with the relative biomass of diatoms; however, they were negatively correlated with the relative biomass of P. antarctica. These results suggest that the protein-like component is most likely produced as a result of biological processes of diatoms in the Amundsen Sea.