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: Text
• Language: English
• Published: 2020
• Subjects: Amundsen Sea; Austral; Southern Ocean; Antarc*; Antarctica
• Online Access: https://doi.org/10.5194/acp-20-5405-2020; https://www.atmos-chem-phys.net/20/5405/2020/

To investigate the characteristics of particulate methanesulfonic acid (MSA (p) ), non-sea-salt sulfate (nss <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="74b4be02f6bf1e477b176a208786a61b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-20-5405-2020-ie00001.svg" width="29pt" height="17pt" src="acp-20-5405-2020-ie00001.png"/></svg:svg> ) 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 µ g m −3 ), whereas its concentration increased sharply up to 0.57 µ g 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 <math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="97cb19aa5ca8b26a6d7fd7d4bad307d2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-20-5405-2020-ie00002.svg" width="29pt" height="17pt" src="acp-20-5405-2020-ie00002.png"/></svg:svg> 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 µ gC m −3 , with averages of 0.087±0.038 and 0.097±0.038 µ gC 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 µ gC m −3 , varying from 0.083 to 0.49 and 0.12 to 0.38 µ gC 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. <math xmlns="http://www.w3.org/1998/Math/MathML" id="M25" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">WSOC</mi><mo>/</mo><msup><mi mathvariant="normal">Na</mi><mo>+</mo></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="62pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="12dae9807fce924696370d5f814c6d36"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-20-5405-2020-ie00003.svg" width="62pt" height="14pt" src="acp-20-5405-2020-ie00003.png"/></svg:svg> and <math xmlns="http://www.w3.org/1998/Math/MathML" id="M26" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><mi mathvariant="normal">WIOC</mi><mo>/</mo><msup><mi mathvariant="normal">Na</mi><mo>+</mo></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="58pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="65d1d9da7da5fef8d6eccf2d81244993"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-20-5405-2020-ie00004.svg" width="58pt" height="14pt" src="acp-20-5405-2020-ie00004.png"/></svg:svg> 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.