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The redox cycle of iron and manganese is a major geochemical process at the boundary layers of lake sediments. Lake Aha, which lies in the suburbs of Guiyang City,Guizhou Province, China, is a medium-sized artificial reservoir with seasonally anoxic hypolimnion. Long-term sedimentary accumulation of iron and manganese resulted in their enrichment in the upper sediments. In the anoxic season, Fe2+ and Mn2+, formed by biological oxidation, would diffuse up to overlying waters from sedlments. However, the concentration of Fe2+ increased later and decreased earlier than that of Mn2+. Generally, sulfate reduction occurred at 6 cm below the sediment-water interface. Whereas, in the anoxic season, the reduction reached upper sediments, inhibiting the release of Fe2+. The Fe concentration of anoxic water is quickly decreased from high to low as a result of reduction Of the sulphur system.
The redox cycle of iron and manganese is a major geochemical process at the boundary layers of lake sediments. Lake Aha, which lies in the suburbs of Guiyang City, Guizhou Province, China, is a medium-sized artificial reservoir with seasonally anoxic hypolimnion. Long -term sedimentary accumulation of iron and manganese resulted in their enrichment in the upper sediments. In the anoxic season, Fe2 + and Mn2 +, formed by biological oxidation, would diffuse up to overlying waters from sedlments. However, the concentration of Fe2 + increased later Early than that of Mn2 +. Generally, sulfate reduction occurred at 6 cm below the sediment-water interface. Whereas, in the anoxic season, the reduction reached upper sediments, inhibiting the release of Fe2 +. The Fe concentration of anoxic water is rapidly decreased from high to low as a result of reduction Of the sulfur system.