Bacterial dominance in subseafloor sediments characterized by methane hydrates

FEMS Microbiology Ecology
By: , and 



The degradation of organic carbon in subseafloor sediments on continental margins contributes to the largest reservoir of methane on Earth. Sediments in the Andaman Sea are composed of ~ 1% marine-derived organic carbon and biogenic methane is present. Our objective was to determine microbial abundance and diversity in sediments that transition the gas hydrate occurrence zone (GHOZ) in the Andaman Sea. Microscopic cell enumeration revealed that most sediment layers harbored relatively low microbial abundance (103–105 cells cm−3). Archaea were never detected despite the use of both DNA- and lipid-based methods. Statistical analysis of terminal restriction fragment length polymorphisms revealed distinct microbial communities from above, within, and below the GHOZ, and GHOZ samples were correlated with a decrease in organic carbon. Primer-tagged pyrosequences of bacterial 16S rRNA genes showed that members of the phylum Firmicutes are predominant in all zones. Compared with other seafloor settings that contain biogenic methane, this deep subseafloor habitat has a unique microbial community and the low cell abundance detected can help to refine global subseafloor microbial abundance.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Bacterial dominance in subseafloor sediments characterized by methane hydrates
Series title FEMS Microbiology Ecology
DOI 10.1111/j.1574-6941.2012.01311.x
Volume 81
Issue 1
Year Published 2015
Language English
Publisher Federation of European Microbiological Societies (FEMS)
Contributing office(s) Pacific Coastal and Marine Science Center
Description 11 p.
First page 88
Last page 98
Other Geospatial Andaman Sea
Online Only (Y/N) N
Additional Online Files (Y/N) N