[Effect of environmental factors on bacterial community in Lake Dongping sediment]

In order to investigate the effect of environmental factors on the bacterial composition of Lake Dongping sediment.

We set six sampling points in Lake Dongping and sampled once in July and once October. Terminal Restriction Fragment Length Polymorphism (T-RFLP) method was used to analyze the bacterial diversity. Ammonium nitrogen (NH4(+)-N) , nitrate nitrogen (NO3(-)-N) , total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC) and water depth were measured.

T-RFLP profiles showed high similarity among samples. However, bacterial diversity indices were significant difference in various samples. The richness, diversity, and evenness in samples which were collected in dry season (October) were generally higher than those in wet season (July), and the bacterial species dominance was higher in wet season than that in dry season. Principal Component Analysis showed that the structure of bacterial communities in sample 2B was marked different from the other samples. The results of Canonical Correspondence Analysis suggested that the abundance of 558 bp T-RF was negatively correlated with NH4(+)-N, NO3(-)-N, TN, TP and TOC, but positively correlated with TOC/TN and the water depth; the abundance of 64.5, 164, 509, and 543 bp T-RFs were positively correlated with NH4(+)-N, NO3(-)-N, TN, TOC, TOC/TN and the water depth. The dominant bacteria in Lake Dongping sediments were Firmicutes and Proteobacteria.

Environmental factors affect bacterial diversity of Lake Dongping sediments, although affect less on indigenous bacteria.