抄録
The rates of sulfate reduction and methane production in surface sediment were surveyed with some environmental factors at four different sites in the inner part of Tokyo Bay from May to October, 1990. Dissolved oxygen in bottom water was almost depleted in August and September at the sites where the bottom has been dredged down, while at the sites of natural sea bed there was mostly more than 1mg O2·l-1. The sulfate reduction rate was measured by a radiotracer method. The rate was much higher at the dredged sites compared with the sites of natural bed. The sulfate reduction rate per area at the dredged site increased from May and reached the highest rate, 4.2 mmol m-2·d-1 in September. On the other hand, at the sites of natural bed the rate was nearly constant and less than 0.8 mmol m-2·d-1. The relatively high rate per area of methane production was observed only at the dredged site and its seasonal change was very similar to that of sulfate reduction. These showed that sulfate reduction and methane production were active in the sediments where the bottom water was apt to be stagnant and thereby was deoxygenated.
