Microbial Community Characteristic of Soils with Different Vegetation in Tidal Flat in Hangzhou Bay

Microbial functional diversity in tidal flat in Hangzhou Bay were investigated to study the possible influences of vegetation on soil microbial community in October, 2011. Surface(0-10 cm) and subsurface(10-20 cm) soils from Scirpus mariqueter, Phragmites australis, Spartina alterniflora tidal flat as well as the soil from bare tidal flat were collected and analyzed in laboratory. Spread-Plate and the Biolog-Eco technique were utilized together for microbial community analysis. The numbers of 3 major groups(bacteria, fungi and actinomycetes) in soils were counted separately. The difference among 4 types of soils were analyzed via curve fitting, principal component analysis and variance analysis. The results showed that compared with the bare flat, the soils with vegetations had more microorganisms. For the surface soils, the number of bacteria and fungi in the soil of Spartina alterniflora tidal flat was the maximum, the other ones were Phragmites austra lis, Scirpus mariqueter and bare tidal flat, while for actinomycetes, the order was Phragmites australis, Spartina alterniflora, bare and Scirpus mariqueter tidal flat. For the subsurface soil, the order of bacteria number was Phragmites australis, Spartina alterniflora, bare and Scirpus mariqueter tidal flat; the order of fungi number was Scirpus mariqueter, Phragmites australis, Spartina alterniflora and bare tidal flat; and the order of actinomycetes number was Phragmites australis, bare, Scirpus mariqueter and Spartina alterniflora tidal flat. Therefore the vegetatation might facilated microbial community. In the soil microorganism profile, bacteria was most abundant and determined the number of the whole community in 4 types of soils, which accounted more than 98% in the soils. There some differences of microbial functional diversity were observed among different vegetation types. Significant differences in the microbial function diversity was found between soils of bare and the other soilsof tidal flat(p0.05). Difference of metabolic capacity between the soils from Spartina alterniflo ra and Scirpus mariqueter communities was significant. Soils in Spartina alterniflora tidal flat had the largest numbers and strongest growth activity, followed by Phragmites australis, Scirpus mariqueter and bare Flat. In contrast, soil microbial community in bare flat had higher richness indicated by McIntosh index. This suggested that soil microbial communities in bare flat soil may had more species than the soil with vegetation. Because of a very short succession time in Hangzhou Bay, vegetation development did not changed the microbial community species composition remarkably. It seemed that because the structure and species of microbial communities were not changed by the vegetation fundamentally, 4 kinds of soil microbial communities had similar dominant species. Sugars, amino acids and their derivatives were the major differentiation substrates for the microbial communities in soils intidal flat of Hangzhou Bay.