Microbial Sulfur Cycle in Two Hydrothermal Chimneys on the Southwest Indian Ridge

Huiluo Cao, Yong Wang, On On Lee, Xiang Zeng, Zongze Shao, Pei-Yuan Qian

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67 Scopus citations

Abstract

Sulfur is an important element in sustaining microbial communities present in hydrothermal vents. Sulfur oxidation has been extensively studied due to its importance in chemosynthetic pathways in hydrothermal fields; however, less is known about sulfate reduction. Here, the metagenomes of hydrothermal chimneys located on the ultraslow-spreading Southwest Indian Ridge (SWIR) were pyrosequenced to elucidate the associated microbial sulfur cycle. A taxonomic summary of known genes revealed a few dominant bacteria that participated in the microbial sulfur cycle, particularly sulfate-reducing Deltaproteobacteria. The metagenomes studied contained highly abundant genes related to sulfur oxidation and reduction. Several carbon metabolic pathways, in particular the Calvin-Benson-Bassham pathway and the reductive tricarboxylic acid cycles for CO $^{2} fixation, were identified in sulfur-oxidizing autotrophic bacteria. In contrast, highly abundant genes related to the oxidation of short-chain alkanes were grouped with sulfate-reducing bacteria, suggesting an important role for short-chain alkanes in the sulfur cycle. Furthermore, sulfur-oxidizing bacteria were associated with enrichment for genes involved in the denitrification pathway, while sulfate-reducing bacteria displayed enrichment for genes responsible for hydrogen utilization. In conclusion, this study provides insights regarding major microbial metabolic activities that are driven by the sulfur cycle in low-temperature hydrothermal chimneys present on an ultraslow midocean ridge. IMPORTANCE There have been limited studies on chimney sulfides located at ultraslow-spreading ridges. The analysis of metagenomes of hydrothermal chimneys on the ultraslow-spreading Southwest Indian Ridge suggests the presence of a microbial sulfur cycle. The sulfur cycle should be centralized within a microbial community that displays enrichment for sulfur metabolism-related genes. The present study elucidated a significant role of the microbial sulfur cycle in sustaining an entire microbial community in low-temperature hydrothermal chimneys on an ultraslow spreading midocean ridge, which has characteristics distinct from those of other types of hydrothermal fields.
Original languageEnglish (US)
JournalMBIO
Volume5
Issue number1
DOIs
StatePublished - 2014
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2021-11-24
Acknowledged KAUST grant number(s): SA-C0040/UK-C0016
Acknowledgements: This study was supported by a grant from the National Basic Research Program of China (973 Program, no. 2012CB417304), a grant (DY125-15-R-01) from the China Ocean Mineral Resources Research & Development Association (COMRRDA12SC02), and awards from the Sanya Institute of Deep-sea Science and Engineering of (SIDSSE-201206), Chinese Academy of Science (CAS), and the King Abdullah University of Science and Technology in Saudi Arabia to P.-Y.Q. (SA-C0040/UK-C0016).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • Virology
  • Microbiology

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