Diversity of microorganisms in sediments of the Jiaojiang Estuary as estimated by Biolog and PCR-DGGE
Biolog和PCR-DGGE技术解析椒江口沉积物微生物多样性

Biolog and PCR-DGGE methods were used to estimate the catabolic and genetic diversity of microorganisms in the surface sediments at six sites in the Jiaojiang Estuary. The package CANOCO was used to determine the correlation between microbial diversity and physiochemical parameters. It was shown by Biolog that the microbial metabolic activity was in the order of intertidal zone and mouth of the estuary>within the mouth>outside the mouth.The values of Shannon-Wiener index for microbial carbon sources ranged from 2.09 to 3.25 in the order of intertidal zone and mouth of the estuary>within the river course > near the mouth > outside the mouth. The use efficiency of different carbon sources for microorganisms was similar in the intertidal zone, mouth of the estuary and within the estuary. However, different use efficiencies of carbon sources were observed near and outside the mouth, where the use efficiency of polymers for microorganisms was much higher than those of amino acids or amine. The DGGE results indicated high spatial heterogeneity of bacterial community structures along the salinity gradient and high similarity (82.27%) of the bacterial community structure between the two sampling sites in the intertidal zone. The values of Shannon-Wiener index for bacterial community structure ranged from 1.68 to 2.87 in the order of intertidal zone > mouth of the estuary > outside the mouth > near the mouth > within the river course. Redundancy gradient analysis (RDA) showed that the distribution of organic matter and nitrobenzene mainly explained the change of microbial catabolism. On the other hand, Canonical correspondence analysis (CCA) showed that the bacterial community structure might be significantly influenced by nitrobenzene and PAHs. Therefore, we concluded that the diversity of microbial catabolism and community structure in the surface sediments of Jiaojiang Estuary was influenced by both the estuarine physicochemical conditions and anthropogenic pollution.