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doi:10.2204/iodp.proc.347.105.2015

Microbiology

A Rumohr core was obtained from Hole M0061K to sample the uppermost 0–1 m of sediment specifically for cell counts and for onshore microbiology (DNA extraction and analysis). Counts of microbial cells were made on board the ship by fluorescence microscopy only using acridine orange direct count (AODC).

A total of 13 sediment samples were counted for microbial cell numbers on the ship (Table T10) using epifluorescence microscope counting techniques. Microbial cell abundance was very high (Fig. F20), with a maximum of 5.41 × 109 cells/cm3 at 0.04 mbsf decreasing linearly to a minimum of 6.90 × 108 cells/cm3 at 0.92 mbsf. This represents approximately an eight-fold decrease in cell numbers over 88 cm. All cell counts of this hole, apart from the uppermost sample at 0.01 mbsf, were very high, with all data values above the upper prediction limit of the global regression of prokaryote cells with depth.