The proposed on a new field of "submarine microbial geotechnics" for conservation and utilization of deep-sea areas

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K18909
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Civil engineering and related fields
• Research Institution: Hiroshima University (2019-2021); Toyama Prefectural University (2017-2018)
• Principal Investigator: Hata Toshiro 広島大学, 先進理工系科学研究科(工), 教授 (30435424)
• Co-Investigator(Kenkyū-buntansha): 千葉 元 大島商船高等専門学校, 商船学科, 教授 (20369961) ; 八木 光晴 長崎大学, 水産・環境科学総合研究科(水産), 准教授 (90605734)
• Project Period (FY): 2017-06-30 – 2022-03-31
• Keywords: 地盤工学 / 海洋環境 / 微生物固化 / マイクロプラスチック

Outline of Final Research Achievements

In this study, the creation of a new field of "seafloor microbial time engineering" is proposed that utilizes the functions of microorganisms already living in situ as a ground improvement technology applicable to the development of mineral and energy resources in the deep sea area, which is expected to be utilized in the near future. Specifically, we analyzed the microbial community structure of core samples collected from deep-sea areas at low temperatures and high pressures and evaluated the degradation characteristics of cement-improved soil using isolated microorganisms.The spread of the new coronavirus infection during the period of the project severely restricted sample installation and collection using the university's training ship. Therefore, we focused on microplastics, which are urgently needed, and proposed a method for detecting them in marine sediments using equipment commonly used in geotechnical engineering.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

海底に眠る未利用の鉱物・エネルギー資源の開発にあたっては原位置の生態系を可能な限り活用しつつ，環境への影響を最小限とした条件の下で必要とされる地盤強度等の機能強化が重要と考えられる．本研究では，このような観点を含めた「海底微生物地盤工学」の提案を目標とし，①深海底から回収した土壌サンプルから目的微生物を効率的に単離する方法，②セメントと微生物の組み合わせることによる長寿命化，③新たな環境問題として関心が高まっているマイクロプラスチックの堆積層内への蓄積状況の迅速評価法の提案，を行った．本検討の結果から，地盤工学的観点からの海洋微生物活用方法と，地盤工学的視点からのMP迅速検出法を提案できた．