Evolution process of microbes in subseafloor

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03956
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental agriculture(including landscape science)
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: HOSHINO Tatsuhiko 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(高知コア研究所), 主任研究員 (30386619)
• Co-Investigator(Kenkyū-buntansha): 浦本 豪一郎 高知大学, 海洋コア総合研究センター, 特任助教 (70612901)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 海底下堆積物 / 微生物

Outline of Final Research Achievements

Below the seafloor, which accounts for 70% of the Earth's surface, there is a unique ecosystem that is different from the surface biosphere, including ocean and soil, and a huge number of microorganisms have been confirmed to exist. In this study, we investigated how the ecosystem was constructed in the low energy subseafloor environment by analyzing sediments from 0-600 m below the seafloor. Microbial community structure in subseafloor differed significantly between anaerobic-eutrophic and aerobic-oligotrophic environments, with the archaea/bacteria ratio in the former being significantly higher than in the latter. The proportion of archaeal cells in the total sediment was estimated to be about 37%, comparable to that in the ocean.

Free Research Field

環境微生物学

Academic Significance and Societal Importance of the Research Achievements

統一された高精度なDNA分析により、全地球レベルで海底下堆積物中の微生物群集の比較解析を世界で初めて行なった。我々の研究成果は、海底下の生態系がどのように構築されてきたのか、どの程度多様なのかという基礎的ではあるがこれまでに分かっていなかった問題の答えを与えるものである。また、本研究成果は、地上のエネルギーに満ちた環境とは全く異なる海底下という極限環境でどのように生命が進化・適応してきたのか明らかにするための進化学的研究の礎となるものである。