home > bioproject > PRJDB2548
identifier PRJDB2548
type bioproject
sra-study  DRP001073
organism marine sediment metagenome
title Metabolically active microbial communities in marine sediment under high-CO2 and low-pH extremes
description Sediment-hosting hydrothermal systems in the Okinawa Trough maintain a large amount of liquid, supercritical and hydrate phases of CO2 in the seabed. The emission of CO2 may critically impact the geochemical, geophysical and ecological characteristics of the deep-sea sedimentary environment. So far it remains unclear whether microbial communities that have been detected in such high-CO2 and low-pH habitats are metabolically active, and if so, what the biogeochemical and ecological consequences for the environment are. In this study, RNA-based molecular approaches and radioactive tracer-based respiration rate assays were combined to study the density, diversity and metabolic activity of microbial communities in CO2-seep sediment at the Yonaguni Knoll IV hydrothermal field of the southern Okinawa Trough. In general, the number of microbes decreased sharply with increasing sediment depth and CO2 concentration. Phylogenetic analyses of community structure using reverse-transcribed 16S ribosomal RNA showed that the active microbial community became less diverse with increasing sediment depth and CO2 concentration, indicating that microbial activity and community structure are sensitive to CO2 venting. Analyses of RNA-based pyrosequences and catalyzed reporter deposition-fluorescence in situ hybridization data revealed that members of the SEEP-SRB2 group within the Deltaproteobacteria and anaerobic methanotrophic archaea (ANME-2a and -2c) were confined to the top seafloor, and active archaea were not detected in deeper sediments (13–30 cm in depth) characterized by high CO2. Measurement of the potential sulfate reduction rate at pH conditions of 3–9 with and without methane in the headspace indicated that acidophilic sulfate reduction possibly occurs in the presence of methane, even at very low pH of 3. These results suggest that some members of the anaerobic methanotrophs and sulfate reducers can adapt to the CO2-seep sedimentary environment; however, CO2 and pH in the deep-sea sediment were found to severely impact the activity and structure of the microbial community.
data type DDBJ SRA Study
external link
sra-run  DRR012964DRR012965DRR012966DRR012967DRR012968
sra-submission  DRA001031
biosample  SAMD00012547SAMD00012551SAMD00012550SAMD00012548SAMD00012549
sra-study  DRP001073
sra-sample  DRS011696DRS011697DRS011698DRS011699DRS011700
sra-experiment  DRX011854DRX011855DRX011856DRX011857DRX011858
distribution JSONJSON-LD
status public
visibility unrestricted-access
dateCreated 2014-05-12T00:46:27+0000
dateModified 2014-05-12T00:46:27+0000
datePublished 2014-05-12T00:46:27+0000