[Bacterial flora analysis of sediment samples from Doukai Bay in Kitakyushu City]

The bacterial flora of 8 sediment samples taken from Doukai Bay in Kitakyushu City in May, 2006 was analyzed by using the culture-independent molecular method. The total bacterial numbers determined by epifluorescence microscopic method were in the range of 2.6 x 10(8) to 6.4 x 10(8) cells/g. The results of bacterial flora analysis suggested that unknown bacterium comprised over 80% of total bacterial flora in the sea sediment samples. Regarding the pathogenic bacteria, although 8 of the Vibrio species, 1 of the Staphylococcus species, and 2 of the Mycobacterium species were detected in the sediment samples, their frequency was low. A large proportion of bacteria related to sulfur circulation, such as sulfur-oxidizing bacteria (10.9 to approximately 30.5%) and sulfate-reducing bacteria (19.6 to approximately 25.1%), was detected in all of the samples from sea sediment. A remarkable difference in bacterial flora between ground soil and sea sediment was clarified by this experiment.