Microbial Community Analysis of the Costa Rica Margin from a Metagenomic Perspective

The taxonomic distribution and metabolic capabilities of microbial communities in the subseafloor are poorly understood. In this study we aimed to analyze the microbial community of samples obtained from the Costa Rica margin in two different sites, one where three samples were collected at 2 meters below the sea floor (mbsf), 33 mbsf and 93 mbsf, and another from 22 mbsf to 45 mbsf. Whole community analysis of conserved gene markers show that the microbial community varies with depth, in composition as well as in average genome size. Genome sizes do not increase with depth and metabolic strategies change with streamlined functions at depth. Specific metabolic processes are found to be performed by distinct members of the microbial community. Changes within the microbial populations related to depth, age and geochemistry are able to be investigated.