Microbial cell densities of ODP Leg 119 samples (Table 1)

A feasibility study was made of the shipboard determination of living microbial cell densities in deep-sea sediments using fluorescence microscopy and the DAPI staining technique. In sediments down to 38 m below seafloor the number of living bacterial cells per milliliter of sediment ranged from near 0 to near 10**6, which is well within the range of microbial densities reported from aquatic and sedimentary environments elsewhere. We suggest that this method be used on future ODP drilling cruises, where recovery of carbon-enriched ancient sediments is expected, to verify the long-term diagenetic influence of living microbes in black shale sequences.