日本地球惑星科学連合2018年大会

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[JJ] Eveningポスター発表

セッション記号 A (大気水圏科学) » A-OS 海洋科学・海洋環境

[A-OS19] 海洋化学・海洋生物学

2018年5月22日(火) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:小埜 恒夫(国立研究開発法人 水産研究・教育機構)、山田 奈海葉(国立研究開発法人 産業技術総合研究所)、齊藤 宏明(東京大学大気海洋研究所、共同)、伊藤 進一(東京大学大気海洋研究所)

[AOS19-P03] Potential influence of ocean acidification on deep-sea Fe-Mn nodules: An assessment by using artificial seawater

*王 権1,2,3川幡 穂高1,2,3山岡 香子3鈴木 淳3 (1.東京大学 大気海洋研究所、2.東京大学 理学系研究科、3.産業技術総合研究所 地質情報研究部門)

With the continuous rise in CO2 emissions, the pH of seawater may decrease extensively in the coming centuries. Deep-sea environments are more vulnerable to decreasing pH since sediments in deep oceans below the carbonate compensation depth (CCD) are often completely devoid of carbonate particles. In order to assess the potential risk of metal release from deep-sea sediments, the mobility of elements from ferromanganese (Fe-Mn) nodules and pelagic clays was examined. We adjusted the pH of seawaters into predicted values by CO2-induced pH regulation system. Two geochemical reference samples (JMn-1 and JMS-2) were treated with these seawaters to investigate the possible metal releasing from deep-sea sediments in response to pH changes. We found that the solid phases in JMn-1 and JMS-2 affect the pH of the ASW through the reaction between the surface hydroxyl groups and the charged ions/complexes in the ASW. According to our result, the variation in the element concentrations in seawater were mainly affected by sorption-desorption processes, which are primarily determined by changes in the surface charge of the solid phase of deep-sea sediments and ion species in seawaters. The possible releasing of heavy metal such as Mn, Cu, Zn, Cd and toxic elements such as As and Ag should be taken into consideration when assessing the influence of pH changing on deep-sea Fe-Mn nodules and red clays.