Peru Margin subseafloor biosphere
Metagenomic signatures of the Peru Margin subseafloor biosphere
The subseafloor marine biosphere may be one of the largest reserviors of microbial biomass on Earth and has recently been the subject of debate in terms of the composition of its microbial inhabitants, particularly on sediments from the Peru Margin. A metagenomic analysis was made using whole genome amplification and pyrosequencing of sediments from Ocean Drilling Program Site 1229 on the Peru Margin to further explore the microbial diversity and overall community composition within this environment. A total of 61.9 Megabases of genetic material was sequenced from sediments at horizons 1, 16, 32 and 50 meters below seafloor. These depths include sediments from both primarily sulfate-reducing and also methane-generating regions of the sediment column. Many genes of the annotated genes, including those encoding ribosomal proteins, corresponded to those from the Chloroflexi and Euryarchaeota. However, analysis of the 16S small subunit ribosomal genes suggests that Crenarchaeota are the abundant microbial member. Quantitative PCR confirms that uncultivated Crenarchaeota are indeed a major microbial group in these subsurface samples. These findings show that the marine subsurface is a distinct microbial habitat and is different than environments previously studied by metagenomics, especially due to the predominance of uncultivated archaeal groups.
A metagenomic analysis was made using whole genome amplification and pyrosequencing of sediments from Ocean Drilling Program Site 1229 on the Peru Margin to further explore the microbial diversity and overall community composition within this environment.