The distributions and variations of sulfide and redox potential in the sediments of Rushan Bay

Three voyage investigations were conducted in the east flow area of Rushan Bay in June, August and October of 2004, respectively. The results showed that this sea area belonged to the environment of weak redox. The sulfide contents in the surface sediment basically tended to be high in the north and to be low in the south, while the redox potential presented the opposite change tendency. The sulfide contents, in terms of vertical distribution, increased generally with the increase of sediment depth, whereas the redox potential fell with the increase of sediment depth. However, there still existed some more exceptions owing to the effects produced by shellfish culture. In addition, the sulfide contents and redox potentials varied obviously with seasons, the sulfide contents in the three months being in the sequence of AugustJuneOctober, while the redox potential values in the three months being in the sequence of OctoberJuneAugust. Shellfish culture had significant effect on sulfide contents and redox potentials in sediment, resulting in the fact that the sulfide contents in culture area were higher than those in uncultured area, while the redox potentials in culture area were lower than those in uncultured area.