于2010年7—10月,选择浙江省宁波市3个凡纳滨对虾覆膜养殖池塘进行水质、沉积物理化因子的研究,并采用磷脂脂肪酸谱图(PLFA)法研究了沉积微生物在不同养殖阶段的群落结构变化及其与环境因子的相关性。结果表明,在整个凡纳滨对虾养殖期间,沉积物PLFAs组成以饱和脂肪酸、支链脂肪酸和单不饱和脂肪酸为主,多不饱和脂肪酸与环丙烷脂肪酸含量较少。微生物总生物量、细菌生物量和真菌生物量伴随着养殖的进行都明显增加。虽然沉积物微生物是以细菌为主体,但真菌更适应沉积物的环境,因此细菌与真菌的比值在不断降低。G 细菌与G^-细菌的比值表现在养殖后期比中期有所下降,但在末期变化不明显。冗余分析(RDA)表明,微生物总生物量、细菌生物量和真菌生物量与总氮(TN)正相关性最为显著,G 细菌生物量和G^-细菌生物量与NO₂-N、NO₃-N呈现显著的正相关,这些微生物群落结构因子全部和透明度(SD)呈现显著负相关关系。

In order to better understand the important role of sediment microorganisms in material cycle and energy flow of aquaculture pond system,three shrimp(Litopenaeus vannamei)ponds covered with plastic sheet in the bottom in Hengshan,Ningbo were chosen and phospholipid fatty acid(PLFA)analysis methods were used to investigate the sediment microbial community structure and its relationship with physical-chemical factors during a three-month period(from June to September,2010).The results showed that the sediment PLFAs were mainly contributed by the saturated fatty acid,branched fatty acid and monounsaturated fatty acid; the amount of polyunsaturated fatty acid and cyclopropane fatty acid was relatively smaller.The total microbial biomass,bacterial biomass and fungi biomass increased significantly with culture time.The principal component analysis(PCA)of the characteristic PLFAs in different periods showed the total of PC1 and PC2 explained the composition of sediment microbial community structure of 81.4%.Although the majority of microorganisms in the sediment were bacteria,bacteria/fungi ratio decreased significantly with culture time due to the better adaptation of fungi to the sediment habitat.The ratios of G /G^- bacteria in the later culture period were smaller compared to the mid-period,but did not change obviously from later period to final-period.Redundancy analysis(RDA)showed that the total microbial biomass,bacterial biomass and fungi biomass were significantly correlated with the total nitrogen and G bacterium biomass, G^- bacterium biomass were significantly correlated with the NO₂-N,NO₃-N. All of them were negatively correlated with the secchi depth(SD).The experimental results indicated that throughout the whole culture process,environmental factors of this new model ponds showed good consistency and stability.Simultaneously,the diversity of the sediment microbial community and the coordination between the structure variation and the environment are also relatively reasonable.The results also demonstrated that the PLFA technique well explained the microbial community according to the variation of PLFAs’ composition in different periods,and overcame the shortcomings of traditional culturing analyzing methods to a certain extent.

国家科技支撑计划(2011BAD13B08);宁波大学教研项目(JYXMxzh200913)