A method of the Warburg's manometry was reported by C. FURUSAKA for the evaluation of the activity of a sulfate reducer in paddy field soil. It was found that this method could be applied for sea bottom mud, if the mud were washed thrice in advance with a non-oxygen 3% sodium chloride solution in order to remove the sulfate present in the sample.
According to his definition, the activity of hydrogen uptake was designated as a hydrogenase activity of mud (HA value in Table 1). In addition of a sulfite solution to the mud a significant increase in the rate of hydrogen uptake was further observed, the increment caused by the addition of the sulfite solution was designated as a sulfate reducing activity of mud (SRA value in Table 2), which is caused by the action of sulfate reducing bacteria in the mud.
The mud samples collected from a fish farm bottom in the Seto Inland Sea were determined by a modified method. Considering the results in Table 2, there was no activity (SRA) at the layer from 0 to 2 cm mud depth, but considerable activity at the 10 cm mud depth. Moreover, it was suggested that the activities varied seasonally, rather higher in autumn than in summer and null in winter.