At Site 1274 three rock and two fault gouge intervals were collected to characterize the microbial community inhabiting this environment. The rock samples are variably serpentinized peridotite (Samples 209-1274A-8R-2 [Piece 16, 89–99 cm] [75% alteration], 15R-2 [Piece 7, 54–63 cm] [96% alteration], and 27R-1 [Piece 6, 69–78 cm] [90% alteration]). The lower fault gouge consisted of serpentine, magnetite, and nontronite mud (interval 209-1274A-23R-2, 121–133 cm), whereas the upper fault gouge (interval 23R-2, 71–83 cm) was a serpentine and magnetite mud.
Both the rock and mud samples were prepared as described in "Igneous Rocks" in "Microbiology" in the "Explanatory Notes" chapter. Sample 209-1274A-27R-1 (Piece 6) was sealed in a nitrogen-filled container and stored in a 4°C refrigerator for 12 days before it was cultured. Additionally, internal fragments of the fault gouge (~0.5 g each) were inoculated into nutrient broth. These samples were incubated at room temperature and observed daily for signs of microbial growth. Two other fragments of the same size were dissolved in sterile artificial seawater (5 mL each) by shaking the samples for ~5 min. After allowing the clay to settle, 1 mL of each sample was stained with SYBR gold nucleic acid stain and observed for microbial presence via epifluorescent microscopy. No bacteria or viruses were observed in either of the samples.
The type and extent of contamination caused by drill fluids was evaluated as described in "Contamination Tests" in "Microbiology" in the "Explanatory Notes" chapter. Samples 209-1274A-8R-2 (Piece 16), 15R-2 (Piece 7), and 27R-1 (Piece 6) were rinsed in nanopure water, and the collected water (50, 41, and 38 mL) was filtered and examined under a fluorescence microscope. For Sample 209-1274A-8R-2 (Piece 16), microsphere concentration was ~340 microspheres/mL of wash. A 0.6-g interior piece of the sample was examined under a fluorescence microscope to detect microsphere penetration, and no microspheres were detected. For Sample 209-1274A-15R-2 (Piece 7), microsphere concentration was >140 microspheres/mL of wash. A 0.15-g piece of the interior of the sample contained no visible microspheres. For Sample 209-1274A-27R-1 (Piece 6), no microspheres were observed in the wash water sample in 20 random fields of view. Only a single microsphere was seen on the entire filter. We cannot determine if the single microsphere represents a very low concentration of microspheres reaching the core or inadvertent contamination during handling. In either case, we consider that the microsphere contamination test on this sample failed. Perfluorocarbon tracer was not used in this hole.
One liter of surface water and 1.2 L of bottom water were collected and prepared for deoxyribonucleic acid (DNA) analysis and direct counts as described in "Seawater and Water Samples" in "Microbiology" in the "Explanatory Notes" chapter. Results of direct counts of bacteria and viruses from the bottom water were 188.7 bacteria/mL of water and 1132.2 viruses/mL of water. The salinity of this water was 34 psu, which eliminates the possibility that the low counts were due to dilution from nanopure water in the WSTP.
Table T12 is a summary of atmospheric and surface water data for the period of 14–19 June 2003. For surface water direct count data, 1 mL of water was stained as described in "Seawater and Water Samples" in "Microbiology" in the "Explanatory Notes" chapter. One milliliter of funnel rinse water was used as a control. Salinity, temperature, and pH values for all surface water values varied; salinity ranged 36.5–37.0 psu, temperature 25.5°–26.1°C, and pH 7.96–7.98. Surface water samples were collected between 1225 and 1354 hr. Air samples were collected for culture-based studies between 0652 and 1845 hr. Air sample volumes ranged from 313.2 to 12,040.5 L per sample. Microbial growth (colony forming units) was for the total volume at 48 and >96 hr of incubation (Table T12). Air temperatures, humidity, wind speed, and wind direction ranged 25.6°–26.2°C, 68.1%–79.6%, 3.9–6.3 m/s, and 65°–105°, respectively. Samples for shore-based analysis of bacterial community DNA and bacteria and viral direct counts were collected daily and stored according to protocol.