Distribution of Microbial Community in the Sediments of the Daliao River Water System, China

Fluorescence in situ hybridization (FISH) method was used to investigate the phylogenetic composition of river sediment from the Daliao River and near estuary (China). For surface sediments from different locations of the river and estuary, the total cell determined by DTAF (5-([4, 6-Dichlorotriazin-2-yl]amino) fluorescein) staining ranged 4.2 times 10⁸ - 16.2 times 10⁸ cell cm^-3, bacteria number determined by FISH with EUB 338 probe ranged 3.2 times 10 - 9.5 times 10⁸ cell cm^-3. Up to 58-82% of DTAF counts can be identified by domain bacteria, among which, alpha-, alpha- and gamma-protebacteria summed up to 40%. Vertical distributions of microbial population and composition was also investigated in a core sediment sample (43 cm) taken from the estuary. Relative higher total cell number was found in the upper (0-5 cm) and middle part of the core sediment (23.5-29.5 cm). Total cell count ranged 7.9 times 10⁸-20.1 times 10⁸ cell cm^-3. About 62-85% of the total cell could be affiliated to domain bacteria. alpha-, beta- and gamma-protebacteria widely distributed in the core sediment, with gamma-protebacteria as the most abundant group which made up 9.8-40.8% of total cell count. Archaea was detected at all sediment depths, and it account for 1.0-11.8% of total DTAF cell count.