Comparative analysis of microbial communities in iron-dominated flocculent mats in deep-sea hydrothermal environments

Hiroko Makita, Sakiko Kikuchi, Satoshi Mitsunobu, Yoshihiro Takaki, Toshiro Yamanaka, Tomohiro Toki, Takuroh Noguchi, Kentaro Nakamur, Mariko Abe, Miho Hirai, Masahiro Yamamoto, Katsuyuki Uematsu, Junichi Miyazaki, Takuro Nunoura, Yoshio Takahashi, Ken Takai

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


It has been suggested that iron is one of the most important energy sources for photosynthesis-independent microbial ecosystems in the ocean crust. Iron-metabolizing chemolithoautotrophs play a key role as primary producers, but little is known about their distribution and diversity and their ecological role as submarine iron-metabolizing chemolithotrophs, particularly the iron oxidizers. In this study, we investigated the microbial communities in several iron-dominated flocculent mats found in deep-sea hydrothermal fields in the Mariana Volcanic Arc and Trough and the Okinawa Trough by culture-independent molecular techniques and X-ray mineralogical analyses. The abundance and composition of the 16S rRNA gene phylotypes demonstrated the ubiquity of zetaproteobacterial phylotypes in iron-dominated mat communities affected by hydrothermal fluid input. Electron microscopy with energy-dispersive X-ray microanalysis and X-ray absorption fine structure (XAFS) analysis revealed the chemical and mineralogical signatures of biogenic Fe-(oxy)hydroxide species and the potential contribution of Zetaproteobacteria to the in situ generation. These results suggest that putative iron-oxidizing chemolithoautotrophs play a significant ecological role in producing iron-dominated flocculent mats and that they are important for iron and carbon cycles in deep-sea low-temperature hydrothermal environments.

Original languageEnglish
Pages (from-to)5741-5755
Number of pages15
JournalApplied and environmental microbiology
Issue number19
Publication statusPublished - 2016

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Ecology
  • Applied Microbiology and Biotechnology


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