Vertical profiles of arsenic and arsenic species transformations in deep-sea sediment, Nankai Trough, offshore Japan

Harue Masuda*, Haruka Yoshinishi, Shigeshi Fuchida, Tomohiro Toki, Emilie Even

*この研究の対応する著者

研究成果: Article査読

2 被引用数 (Scopus)

抄録

Concentrations of arsenic (As) and its chemical forms were determined on deep-sea sediments drilled at three sites of Nankai Trough, off the Kii Peninsula, Japan. Those sediments were analyzed to document the behavior of As in relation to methane hydrate formation and the deep biosphere. The analytical results showed the total As concentration of interstitial water (IW) and squeezed cake (SC) ranged from 0.9 to 380 ppb and from 3 to 14 ppm (average, 6.4 ppm), respectively. The sediments from Site C0002, of which sediment column was the longest down to 2200 m below the seafloor (mbsf) among the studied three drilling sites, were analyzed for the host phase transformation of As. The total concentration of As of IW and SC from 200 to 500 mbsf, where methane hydrate zone was included, was higher than those from the uppermost 200 m. Concentration of As was ultimately controlled by pH. Also, organoarsenicals, such as methylarsonic acid (MMA) and arsenobetaine (AsB), were detected in the sediment column, implying that these organoarsenicals appeared in relation to the in situ microbial activities. These observations suggest that As becomes mobilized directly or indirectly as a result of microbial activity in deep-sea sediments. [Figure not available: see fulltext.]

本文言語English
論文番号28
ジャーナルProgress in Earth and Planetary Science
6
1
DOI
出版ステータスPublished - 2019 12月 1

ASJC Scopus subject areas

  • 地球惑星科学(全般)

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