IODP Expedition 330 enrichments

The aquifer in subseafloor igneous basement is a massive, continuous microbial substrate, yet sparingly little is known about life in this habitat. The work to date has focused largely on describing microbial diversity in young basement (65 Ma, and that seamounts can act as mid-plate conduits for fluids into and out of the subsurface aquifer in older crustal settings. Here we test the hypothesis that microbial life exists in subseafloor basement >65Ma using samples collected from the Louisville Seamount Chain via seafloor drilling. Bacterial 16S rRNA genes were amplified for the V4V6 region from enrichment incubations started during Expedition 330 targeting general heterotrophs (with 1% and 10% marine broth media), heterotrophic sulfur oxidizers, and heterotrophic and autotrophic iron reducers.