文摘
In this work, enzymatic and microbial degradation of organic matter in Lake Hongfeng, Guizhou Province, is described in terms of variations in DNA, α-glucosidase and sulfatereduction bacteria (SRB). Organic matter is degraded by microbes and extracellular enzymes excreted by the former, to a relatively low content below the 11-cm sediment depth. The distribution of DNA indicated that microbes are very active at the 9-cm sediment depth, where organic matter is degraded by microbes intensively. The contents of α-glucosidase are highest in suspend layer (0.75 μmol · min?· g? dry sediments), showing that starch and hepatin in organic matter have been degraded intensively. α-glucosidase activity weakens with sediment depth. At the 11-cm depth where the degradation of organic matter started to slow down, α-glucosidase activity has been reduced to 0.17 μmol · min? · g? (dry sediment). Molecular biological research indicated that sulfate reduction bacteria (SRB) are distributed mainly at the upper 7-cm sediments in Lake Hongfeng. Combined with the results of research on the variations of organic matter and SO 4 2?/sup> , it is indicated that SO 4 2?/sup> is unlikely to become an important electron acceptor and sulfate reduction is not limited by the supply of organic matter in Lake Hongfeng.