Takuro NunouraManabu NishizawaMiho HiraiShigeru ShimamuraPhurt HarnvoravongchaiOsamu KoideYuki MoronoToshiaki FukuiFumio InagakiJunichi MiyazakiYoshihiro TakakiKen TakaiTokyo Institute of TechnologyMahidol UniversityJapan Agency for Marine-Earth Science and TechnologyJapan Agency for Marine-Earth Science Technology (JAMSTEC)2019-08-232019-08-232018-01-01Microbes and Environments. Vol.33, No.2 (2018), 186-19413474405134263112-s2.0-85049657646https://repository.li.mahidol.ac.th/handle/20.500.14594/44881© 2018, Japanese Society of Microbial Ecology. All rights reserved. The Challenger Deep is the deepest ocean on Earth. The present study investigated microbial community structures and geochemical cycles associated with the trench bottom sediments of the Challenger Deep, the Mariana Trench. The SSU rRNA gene communities found in trench bottom sediments were dominated by the bacteria Chloroflexi (SAR202 and other lineages), Bacteroidetes, Planctomycetes, “Ca. Marinimicrobia” (SAR406), and Gemmatimonadetes and by the archaeal α subgroup of MGI Thaumarchaeota and “Ca. Woesearchaeota” (Deep-sea Hydrothermal Vent Euryarchaeotic Group 6). The SSU rRNA gene sequencing analysis indicated that the dominant populations of the thaumarchaeal α group in hadal water and sediments were similar to each other at the species or genus level. In addition, the co-occurrence of nitrification and denitrification was revealed by the combination of pore water geochemical analyses and quantitative PCR for nitrifiers.Mahidol UniversityAgricultural and Biological SciencesArticleSCOPUS10.1264/jsme2.ME17194