Hadal biosphere: Insight into the microbial ecosystem in the deepest ocean on Earth

• DOI: 10.1073/pnas.1421816112
• Publication Date: 2015-02-25T22:27:01Z
• Authors: Takuro Nunoura; Yoshihiro Takaki; Miho Hirai; Shigeru Shimamura; Akiko Makabe; Osamu Koide; Tohru Kikuchi; Junichi Miyazaki; Keisuke Koba; Naohiro Yoshida; Michinari Sunamura; Ken Takai
• Keywords: Salinity; 0303 health sciences; 550; Bacteria; Earth, Planet; Oceans and Seas; Molecular Sequence Data; Temperature; Heterotrophic Processes; 15. Life on land; Archaea; Nitrification; Ribosome Subunits, Small; 03 medical and health sciences; Prokaryotic Cells; RNA, Ribosomal; 13. Climate action; 14. Life underwater; Ecosystem

SignificanceAlthough many microbial explorations for hadal sediments began in the 1950s, the hadal water is the least-explored microbial biosphere. In this study, unexpected microbial ecosystems associated with the hadal trench water were discovered down to a 10,257-m water depth in the Challenger Deep of the Mariana Trench, which is the deepest ocean on Earth. We found the enrichment of heterotrophic population in the hadal water (6,000 ∼10,257 m) microbial communities, whereas the chemolithotrophic populations were more abundant in the upper abyssal waters. This observation suggested that the hadal microbial biosphere was supported by the endogenous recycling of organic matter in the hadal waters associated with the trench geomorphology.