Community composition and metabolic potential of subseafloor sediment in the Tonga Trench differ with sedimentary patterns

Hadal environments, in particular deep trenches, are largely under studied and microorganisms that thrive in these ecosystems, under such extreme conditions, are not well understood. Studies done to date suggest that largely unexplored metabolic potential of deep-sea microbes may have both physiological and biogeochemical importance. Here we present the metagenomic analysis of deep trench sediment samples collected at surface, 1 meter below the seafloor (mbsf) and 2 mbsf. Results to date suggest that the microbial community is largely dominated by bacteria (>90%) at all depths, although community structure is not constant through out the sediment column. Patterns of community composition suggest a link between community structure and sedimentary environments. These analyses provide a better understanding of the drivers (e.g. sedimentary structure, low nutrients, high pressure) of microbial communities biogeography and their adaptive metabolic processes to such extreme environmental conditions.