Microbially induced and disrupted memory phenomena during gas-hydrate occurrences in seafloor sediments.

摘要

Sediments collected from various cores in Mississippi Canyon 118 were tested to evaluate the abilities to promote natural gas hydrate formation. Hydrate memory effects of sediments with in-situ seawater were of a major concern. Their possible mechanisms were combined to give an overall hypothesis on the bioproducts-mineral-microorganism system. Unique permanent memory effects in the sediment were found. Temperatures from 50 to 65°C dissipated memory effects by disrupting microbial cell wall.;The catalytic effect of purified surfactin from Bacillus subtilis on hydrate formation was studied in the presence of smectite clays. The interlayer spacings of clays measured by X-ray powder diffraction indicated that hydrate formation and surfactin adsorption on the smectite clays have impacts on their structures.;Laboratory gas sequestering was also conducted by hydrate formation to study the factors that may affect the separation of its hydrate-forming gases. The effects of agitation, temperature, initial pressure and thermal conductors were explored.