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 (517KB)
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17,412,000 Yen (FY1997; 5,739,000 Yen)
The East China Sea is located at the mouth of the Yangtze River. The huge Three Gorges Dam, being constructed in the middle of the river, is expected to lead to changes in river flow that will affect East China Sea water quality. Our aim in this study was to observe the microbial community structure of the East China Sea as a baseline for comparison with future changes. We studied bacterial diversity in East China Sea surface water based on both phenotypes and genotypes. Bacteria from three common marine groups, Alpha-proteobacteria, Gamma-proteobacteria and CFB, were dominant. Some other groups, including Low G+C gram posi.. High G+C gram posi. and relatives of Verrucomicrobium, were also observed. Dominant species in phenotype and genotype analysis were close relatives of Alteromonas macreodii. Phytoplankton diversity were determined using ultrastructural observation method using electro microscope, and flowcytometryanalysis (FCM) method. From ultrastructural observation, 4 different picophytoplankton,Micromonas pussila (Prasinophyceae), Nannochloris-like species (Chlorophyccae), Imantonia rotunda (Haptophyceae) and Synechococcus spp. (Cyanophyceae) were recognized. From FCM analysis, distribution of picophytoplankton were determined as follows; at stations A1, B1 and C1, close to the shore, the cell density ranged 200-700 cells/ml, while at stations B3, B5 and C5, furthest from the shore, the maximum number reached 16,800 cells/ml. From these results, the microflora seems to bedifferent in each site, and FCM and PCR methods could be useful for the routine study of microbial communities and biodiversity in the East China Sea.
Flow cytometry, Picoplankton, PCR, Phylogenetic tree