Degradation of organic matterin the sediments of Hongfeng Reservoir

In this work, the distribution of organic carbon, DNA and lipids in the sediments of Hongfeng Reservoir were described in addition to SO42? profile in pore water. The con- tents of organic carbon in the sediments range from 23.3 to 76.8 mg·g?1, with the peak value appearing at the depth of 8 cm bellow the sediments water interface (SWI), and tend to decrease gradually with sedimentation depth. The concentra- tions of SO42? decreased from 40.50 mg·L?1 to 12.00 mg·L?1 at SWI in top 4 cm sediment, and was kept at 12.0 mg·L?1 bel- low that depth. Newly produced organic carbon can be con- served as long as 14 years in the sediments. The contents of DNA were relatively high in top 9 cm surface sediments, as revealed by agarose gel images, close to those of organic car- bon and sulphate reduction index (SRI). This study shows that bacteria played an important role in organic matter degradation; SO42? is the primary electron acceptor under anaerobic condition in this reservoir; DNA in the lake sedi- ments can provide important information for the study of cycling of nutrient elements in the lake.