新垣 雄光 (アラカキ タケミツ)

Arakaki Takemitsu

写真a

職名

教授

科研費研究者番号

80343375

現在の所属組織 【 表示 / 非表示

  • 専任   琉球大学   理学部   海洋自然科学科   教授  

留学歴 【 表示 / 非表示

  • 1991年08月
    -
    1996年12月

    デューク大学(Duke University)米国  

取得学位 【 表示 / 非表示

  • デューク大学 -  Ph.D  その他 / その他

  • デューク大学 -  M.A (理学)  理学

職歴 【 表示 / 非表示

  • 2005年06月
     
     

      - , University of the Ryukyus, Faculty of Science, Department of Chemistry, Biology, and Marine Science, Marine Chemistry, Associate Professor  

  • 2005年06月
    -
    2010年12月

      琉球大学 理学部 海洋自然科学科 海洋化学講座 准教授  

  • 2011年01月
     
     

      - , 琉球大学 理学部 海洋自然科学科 海洋化学講座 教授  

研究キーワード 【 表示 / 非表示

  • 地球化学

  • 環境化学

  • 大気化学

  • 光化学

  • 環境化学

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研究分野 【 表示 / 非表示

  • 環境・農学 / 環境動態解析

主たる研究テーマ 【 表示 / 非表示

  • 大気エアロゾルに含まれる化学成分の挙動解明

  • 沖縄島における過酸化物(過酸化水素および有機過酸化物)の計測と挙動について

論文 【 表示 / 非表示

  • Heterogeneity and potential aquatic toxicity of hydrogen peroxide concentrations in selected rivers across Japan.

    Sunday MO, Jadoon WA, Ayeni TT, Iwamoto Y, Takeda K, Imaizumi Y, Arakaki T, Sakugawa H

    Science of the Total Environment ( Science of the Total Environment )  733   139349   2020年09月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

     概要を見る

    Hydrogen peroxide (H2O2) is a reactive oxygen species formed in natural water. It is reportedly toxic to aquatic organisms with a predicted no-effect concentration (PNEC) of about 380 nM. In this study, a countrywide investigation of H2O2 concentrations in selected rivers across Japan was conducted to identify rivers that pose toxicity concerns. Twelve rivers with a total catchment area of 13,646 km(2) were selected from different prefectures. Spatial and temporal variation studies showed that the H2O2 concentrations (avg. 320 nM, n = 111) varied by two orders of magnitude (range 212929 nM) across the rivers. The Yamato River in Osaka and Nara prefectures and the Kokubu River in Chiba Prefecture had the highest concentrations at 276669 nM and 2362929 nM, respectively. >75% of the data from the two rivers were either close to or exceeded the PNEC. Most of the results for the other rivers were less than the PNEC. There was a clear seasonal variation in the H2O2 concentrations, with the highest values obtained in summer because of high solar irradiation. The H2O2 concentration had the highest positive correlation (r = 0.61, p < 0.01, n = 111) with the product of dissolved organic carbon and solar radiation intensity, which suggests that these two factors in combination are important in determining the H2O2 concentrations in river water. It was also observed that bigger rivers had lower H2O2 concentration and vice-versa. This shows that the size of a river may influence its H2O2 concentration. This study is the first countrywide survey of H2O2 concentrations in different rivers and evaluation of their relationship with the PNEC. The data provide insight on the factors influencing the concentrations of H2O2 in river water.

  • Preparation of standard materials of aerosol particles for X-ray fluorescence analysis using a small chamber sampling unit

    Nakano, K, Y. Oshiro, S. Azechi, Y. Somada, D. Handa, Y. Miyagi, A. Tanahara, T. Arakaki, A. Itoh

    X-Ray Spectrometry   47   450 - 458   2018年10月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

  • Long-Term Monitoring of Metal Elements in the Total Suspended Particle Aerosols Simultaneously Collected at Three Islands in Okinawa, Japan

    Itoh, A. Y. Oshiro, S. Azechi, Y. Somada, D. Handa, Y. Miyagi, K. Nakano, A. Tanahara, T. Arakaki

    Asian Journal of Atmospheric Environment   12 ( 4 ) 326 - 337   2018年10月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

  • Role of the Fenton Reaction in Coastal Seawater Samples Collected in Okinawa, Japan

    Hamdun Asha M., Higaonna Yumi, Uehara Hiroyuki, Arakaki Takemitsu

    Chemistry Letters ( 公益社団法人 日本化学会 )  46 ( 1 ) 42 - 44   2017年 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

     概要を見る

    <p>We studied the Fenton reaction (Fe(II) + H<sub>2</sub>O<sub>2</sub> → OH + OH<sup>−</sup> + Fe(III)) in coastal seawater samples by measuring Fe(II) and OH radical concentrations during photochemical experiments. Under coastal seawater conditions, the Fenton reaction was found to be an important pathway for H<sub>2</sub>O<sub>2</sub> decomposition in comparison to direct photolysis, but only a minor source of OH. Experimentally observed H<sub>2</sub>O<sub>2</sub> destruction rate constants (<i>k</i>'<sub>H<sub>2</sub>O<sub>2</sub></sub>) could be accounted for by reactions of H<sub>2</sub>O<sub>2</sub> with Fe<sup>2+</sup> and FeOH<sup>+</sup>.</p>

  • Reviews and Syntheses: Ocean acidification and its potential impacts on marine ecosystems

    Mostofa K.

    Biogeosciences ( Biogeosciences )  13 ( 6 ) 1767 - 1786   2016年03月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

     概要を見る

    Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO2 that adds up with dissolved inorganic carbon (dissolved CO2, H2CO3, HCO3-, and CO32-) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The aquatic processes leading to inorganic carbon are substantially affected by increased DOM and nutrients via terrestrial runoff, acidic rainfall, increased PP and algal blooms, nitrification, denitrification, sulfate reduction, global warming (GW), and by atmospheric CO2 itself through enhanced photosynthesis. They are consecutively associated with enhanced ocean acidification, hypoxia in acidified deeper seawater, pathogens, algal toxins, oxidative stress by reactive oxygen species, and thermal stress caused by longer stratification periods as an effect of GW. We discuss the mechanistic insights into the aforementioned processes and pH changes, with particular focus on processes taking place with different timescales (including the diurnal one) in surface and subsurface seawater. This review also discusses these collective influences to assess their potential detrimental effects to marine organisms, and of ecosystem processes and services. Our review of the effects operating in synergy with ocean acidification will provide a broad insight into the potential impact of acidification itself on biological processes. The foreseen danger to marine organisms by acidification is in fact expected to be amplified by several concurrent and interacting phenomena.

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学術関係受賞 【 表示 / 非表示

  • Excellence in Reviewing

    2016年07月   エルゼビア  

    受賞者: 新垣 雄光

科研費獲得情報 【 表示 / 非表示

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その他研究費獲得情報 【 表示 / 非表示

  • 沖縄辺戸岬におけるエアロゾルのサンプリングと無機成分の分析

    研究費種類: 財団・社団法人等の民間助成金  参画方法: その他

    研究種別: 受託研究  事業名: -

    研究期間: 2009年06月  -  2010年03月 

    代表者: 新垣 雄光  資金配分機関: 国立大学法人北海道大学

    直接経費: 2,400,375(円)  間接経費: 719,625(円)  金額合計: 3,120,000(円)