Marine biomarkers deposited on coastal land by the 2011 Tohoku-oki tsunami

Tetsuya Shinozaki, Shigehiro Fujino, Minoru Ikehara, Yuki Sawai, Toru Tamura, Kazuhisa Goto, Daisuke Sugawara, Tomoya Abe

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

To determine how and what kind of marine-sourced biomarkers are transported and deposited on land by tsunami, we collected and analyzed samples of the 2011 Tohoku-oki tsunami deposits and the underlying and overlying soil at Sendai and Odaka, in northeast Japan. Characteristic hydrocarbons, such as short-chain n-alkanes, pristane, and phytane, were detected only in soil layers 0–2 cm below the tsunami deposits at both sites. Dinosterol originated from dinoflagellates was detected in a mud layer overlying sand deposits in Odaka. Such characteristic biomarkers were not detected in soil layers deeper than 2 cm beneath the tsunami deposits at either site, and none was found in the surface soil layer overlying the tsunami deposit in Odaka. Therefore, it is probable that the biomarkers were transported and deposited by the tsunami. The sand layer was highly permeable and low in clay or organic matter to which biomarkers could bind. Any biomarkers deposited with the sand probably leached into the underlying soil or were found in sediments richer in clay and organic matter such as tsunamigenic mud. Sediment samples were collected more than 2 years after the tsunami, indicating that the marine-sourced biomarkers were preserved for at least 2 years in the soil. In addition, a comparative analysis of sediment samples collected earlier indicated that characteristic biomarkers did not remain in the sand layer 3 months after the tsunami. These findings show the potential of using biomarkers as proxies to identify marine-sourced deposits on coastal land.

Original languageEnglish
Pages (from-to)445-460
Number of pages16
JournalNatural Hazards
Volume77
Issue number1
DOIs
Publication statusPublished - 2015 May 1

Keywords

  • 2011 Tohoku-oki tsunami
  • Biomarker
  • Dinosterol
  • Hydrocarbon
  • Northeast Japan
  • Tsunami deposits

ASJC Scopus subject areas

  • Water Science and Technology
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)

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