Microbial communities in iron-silica-rich microbial mats at deep-sea hydrothermal fields of the Southern Mariana Trough
Article first published online: 22 APR 2009
© 2009 Society for Applied Microbiology and Blackwell Publishing Ltd
Volume 11, Issue 8, pages 2094–2111, August 2009
How to Cite
Kato, S., Kobayashi, C., Kakegawa, T. and Yamagishi, A. (2009), Microbial communities in iron-silica-rich microbial mats at deep-sea hydrothermal fields of the Southern Mariana Trough. Environmental Microbiology, 11: 2094–2111. doi: 10.1111/j.1462-2920.2009.01930.x
- Issue published online: 3 AUG 2009
- Article first published online: 22 APR 2009
- Received 5 December, 2008; accepted 14 March, 2009.
The abundance, diversity and composition of bacterial and archaeal communities in the microbial mats at deep-sea hydrothermal fields were investigated, using culture-independent 16S rRNA and functional gene analyses combined with mineralogical analysis. Microbial mats were collected at two hydrothermal areas on the ridge of the back-arc spreading centre in the Southern Mariana Trough. Scanning electron microscope and energy dispersive X-ray spectroscopic (SEM-EDS) analyses revealed that the mats were mainly composed of amorphous silica and contained numerous filamentous structures of iron hydroxides. Direct cell counting with SYBR Green I staining showed that the prokaryotic cell densities were more than 108 cells g−1. Quantitative polymerase chain reaction (Q-PCR) analysis revealed that Bacteria are more abundant than Archaea in the microbial communities. Furthermore, zetaproteobacterial cells accounted for 6% and 22% of the prokaryotic cells in each mat estimated by Q-PCR with newly designed primers and TaqMan probe. Phylotypes related to iron-oxidizers, methanotrophs/methylotrophs, ammonia-oxidizers and sulfate-reducers were found in the 16S rRNA gene clone libraries constructed from each mat sample. A variety of unique archaeal 16S rRNA gene phylotypes, several pmoA, dsrAB and archaeal amoA gene phylotypes were also recovered from the microbial mats. Our results provide insights into the diversity and abundance of microbial communities within microbial mats in deep-sea hydrothermal fields.