Application of the Microbial Population Analysis Methods for the Investigation of Sediment Transfer and Materials Conversion Functions

研究了微生物种群对泥沙迁移现象的适用性。样品主要取自有莱克湾。2005年和2006年，在阿里亚克湾的23个采样点采集样品，用T-RFLP方法研究了β-变形杆菌氨氧化细菌的水平分布。研究发现，部分运行分类单元(OTUS)沿赤阁河进水逆时针方向分布，另一些运行分类单元(OTUS)更多地分布在阿里亚克湾中部。据其他研究人员报道，奇库戈河的进水呈逆时针方向流动，本研究也得出了同样的结果。2007年，于9月29日在5个地点进行了密集抽样，采取了多时间点抽样。采用T-RFLP方法对底泥和底层水样中的细菌群落进行分析。在研究之前，开发了一种新的超声提取DNA的方法，以最少的样本量提高分析的吞吐量。用建立的方法，大部分样品只需超声和稀释即可获得扩增产物。以同样的方法，从样品中的悬浮固体中获得PCR产物。采用聚合酶链式反应-T-RFLP方法对采样日短时间内底水中微生物的行为进行调查。用该方法对底水及其悬浮物样品中微生物种群的动态行为进行了观察。但遗憾的是，在目前的研究中，没有发现底泥迁移与微生物种群变化之间的明确关系。可能有必要找到适合作为示踪剂的关键细菌种类。综上所述，我们开发了一种利用微生物种群结构来监测沉积物行为及其迁移的方法。

The applicability of microbial population to investigate the sediment transfer phenomena was investigated. Samples were obtained mainly from Ariake Bay. In 2005 and 2006, samples were obtained from 23 points in Ariake Bay, and horizontal distribution of beta proteobacterial ammonia oxidizing bacteria was studied by the T-RFLP method. It was found that some of the OTUs (operational taxonomic units) distributed along the counter-clockwise flow of influent from Chikugo-River, and others were found more in the central part of the Ariake-Bay. It has been reported by other researchers that the influent from Chikugo-River has a counterclockwise flow, and the present study gave the same outcome. In 2007, an intensive sampling was done on 29th September at 5 locations with a multiple-time-point sampling. The whole bacterial community in the sediment samples and the bottom water samples were analyzed by the T-RFLP method. Prior to the study, a new DNA extraction method using sonication was developed, to enhance the throughput of the analysis with minimum amount of sample. By the developed method, PCR products were obtained from most of the samples only by sonication and dilution. In the same way, PCR products were obtained from suspended solids in the samples. PCR-T-RFLP method was applied to investigate the behavior of microorganisms in the bottom water within the short period of time on the sampling day. The dynamic behavior of the microbial population in the bottom water and its suspended solids samples were observed by the developed method. But unfortunately, in the present study, clear relationship between the sediment transfer and the microbial population change could not be found. It may be necessary to find key bacterial species that are suitable as a tracer. In conclusion, we developed a method to use microbial population structure to monitor the behavior of sediment and its transfer.