Census of Deep Subseafloor Life: Biogeographical distribution of microbial life in Earth's interior

2017 Fiscal Year Final Research Report

• Project/Area Number: 26251041
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Biodiversity/Systematics
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: INAGAKI Fumio 国立研究開発法人海洋研究開発機構, 海洋掘削科学研究開発センター, 研究開発センター長代理 (50360748)
• Co-Investigator(Kenkyū-buntansha): 星野 辰彦 国立研究開発法人海洋研究開発機構, 高知コア研究所, 主任研究員 (30386619)
• Project Period (FY): 2014-06-27 – 2017-03-31
• Keywords: 海底下生命圏 / アーキア / 微生物群集構造 / デジタルPCR

Outline of Final Research Achievements

To elucidate biogeographical distribution of deep microbial life in the global subseafloor sedimentary environment which accounts for ~70% of the Earth's surface, we extracted environmental genomic DNA from frozen core samples obtained by multiple scientific ocean drilling expeditions in the past decade and performed the comprehensive quantification and sequence analysis of 16S rRNA genes. Consequently, the proportion of Archaea in the global subseafloor sedimentary biosphere was estimated at ~37%, which is nearly consistent with archaeal abundance in the overlying marine environment. In addition, analysis of microbial community structure and taxonomic composition demonstrated that the deep subseafloor biosphere can be categorized into two types: the aerobic microbial ecosystem in the open ocean and the anaerobic microbial ecosystem in the marginal ocean, which populations are persisting vertically into deeper sedimentary habitats.

Free Research Field

地球微生物学　生物地球化学