Jean et al. (2005) isolated and identified indigenous bacteria strains from the sediments of Holes 1202A and 1202D to a depth of 358 mbsf. The isolated sulfate-reducing bacteria show a strong phylogenetic affinity to Bacillus subtilis and Pseudomonas putida strains. Culturing experiments revealed that the isolated bacteria could survive extreme conditions including temperatures >45°C, salinities as high as 60
–65 and pH values as high as 10. Although these bacteria can be adapted to either aerobic or anaerobic conditions and were capable of consuming Fe, Cu2+, Na+, K+, Mg2+, Ca2+, and F–, no associated biogenic minerals have been identified in the sediments to date.
To assess fluid migration and water-sediment interactions at various depths in the drill hole, K.-F. Huang et al. (2005) measured major ions, boron concentrations, and boron isotopic ratios in pore water squeezed from Site 1202 cores. They found that the major ions and boron do not behave conservatively and are likely to be affected by sedimentary diagenetic processes. Apparently, boron released from clays is one of the most important boron sources in pore water, but other processes, such as precipitation of carbonates, low-temperature ash alteration, and interaction with terrigenous sediments also play important roles.
