[A-CC37] [EJ] アイスコアと古環境変動

[ACC37-P07] A year-round observation of sulfur stable isotopic compositions of atmospheric sulfate at Dumont d’Urville, coastal Antarctica

*石野 咲子¹、服部 祥平¹、サバリノ ジョエル²、ルグラン ミシェル²、プリウンカート スザンヌ²、ジュールダン ブルーノ²、吉田 尚弘^1,3 (1.東京工業大学物質理工学院、2.Univ. Grenoble Alpes, CNRS, IRD, IGE, F-38000 Grenoble, France、3.地球生命科学研究所)

キーワード：安定同位体、南極、硫酸

Sulfur stable isotopic compositions (³⁴S/³²S, ³³S/³²S and ³⁶S/³²S) of sulfate in the Antarctic snow and ice cores have been used to investigate the contribution of its sources such as marine biogenic activity and volcanic emissions, as well as its formation pathways (e.g., Patris et al., 2000; Uemura et al., 2016; Baroni et al., 2007). However, temporal variability of those signatures in the present Antarctic atmosphere has never been examined. Here we report a year-round observation of sulfur isotopic compositions of sulfate in aerosol samples collected at Dumont d’Urville (66°40’S, 140°01’E), coastal Antarctica, throughout the year 2011. In summer months, ³⁴S/³²S ratios were similar to the values observed in dimethyl sulfide (DMS) produced by marine biota (Amrani et al., 2013; Oduro et al., 2012), in contrast to ³⁴S depletion during winter, which suggest the contribution of other sources or unknown processes. Throughout the year, ³³S/³²S and ³⁶S/³²S ratios suggested no significant contribution of reactions causing mass independent fractionation.