Characteristics Of Soil Microbial Community In The Poyang Lake Wetland And Its Response To Environmental Change

Soil microorganism is an important component of the wetland ecosystem,and very sensitive to environmental change.Temperature,moisture and substrate availability are three important impact factors for soil microbes in wetland ecosystem.In this study,soil samples at 0-10 cm under depths of seven dominant plant communities were collected along the water table gradient in a typical Poyang Lake wetland.Moreover,soil samples of three dominant plant communities were incubated under different temperature and water treatment.The objectives of this study were(1)to clarify the characteristics of soil microbial communities,and(2)their response to environmental changes such as temperature,moisture and substrate availability in typical Poyang Lake wetland.The main results are were as follows:(1)Proteobacteria、Acidobacteria、Chloroflexi and Actinobacteria etc are the dominant microbial communities in Poyang Lake wetland.(2)The microbial community structure was more similar between soils which has moisture condition or closer spatial locations along the transition from the lakeside beaches to high submerged plant area.For example,the microbial community structure of Triarrhena lutarioriparia L Liu,Zizania latifolia,Phalaris arundinacea Linn and Hydrilla verticillata are similar,and the microbial community structure of Triarrhena lutarioriparia L Liu and Cynodondactylon(Linn.)Pers.are the biggest difference.There are some differences in the change of community types.(3)In the case where the substrate availability does not change significantly(early in the culture experiment),the temperature and water were the dominant environmental factors affecting the soil microbial community;Under different temperature conditions,the abundance and diversity of soil microbial community changed with soil moisture,but the trend was not consistent;In addition,temperature and moisture change does not change the kinds of microbial community,only changed the relative abundance of the microbial community.(4)With the decomposition of soil organic carbon from the early to the late,The decomposition of organic carbon was almost exhausted,and the decomposition of organic carbon was more and more concentrated,soil microbes rely on the survival of the substrate availability decreased,community structure changed greatly.Top 5bacteria of microbial richness from early and medium term “ Proteobacteria 、Acidobacteria 、 Chloroflexi 、 Nitrospirae and Planctomycetes ”turns into“Proteobacteria、Acidobacteria、Firmicutes、Chloroflexi and Nitrospirae”.In addition,Actinobacteria and Verrucomicrobia bacteria significantly increased.