Data report: microbial abundance in subseafloor sediments of the equatorial Pacific Ocean, Expedition 320/321

Abstract

Microbial cell abundances in sediment cores from Integrated Ocean Drilling Program Expedition 320/321 were quantified. Cell abundances varied between sites and with depth between >10 6 cells/cm 3 and <10 3 cells/cm 3 . Even when using cell separation to increase sensitivity, cell abundances fall below the minimum detection limit in the deeper parts of several sites. At many of the sites, cell distribution does not follow the generally observed trend of a continuous decline with depth. Only some of these deviations appear to be correlated with lithologic changes.