Abstract
The factors of eutrophication in lakes are dependent on external loads of nutrients carried from inflowing rivers and internal loads of nutrients leached from bottom sediment. In this study, dissolution tests were conducted using the sediment obtained before and after a large-scale flood to understand the impact that floods have on sediment and water quality. In addition, microbial communities in the sediment were analyzed using new generation sequencer to determine the behavior of in situ materials and the condition of environment. The dissolution tests showed that the NH4-N dissolution rate under anaerobic condition had increased at the sampling site near the mouth of inflowing river after the flood. In contrast, the PO4-P dissolution rate had decreased. Microbial community analysis results at the sampling site showed no large difference between surface and deep layer of bottom sediment. This suggests that the bottom sediment was disturbed by high wind.
