Study Of Hydrostatic Pressure Effects On Phosphorus Cycling And Transformation With Microorganism In The Sediment Of Reservoir

The release of internal phosphorus in reservoir is a key cause of eutrophication.This article on high hydrostatic pressure features,which is in the multi phase interface of the Heihe Jinpen Reservoir between water and sediment,applies tradtional dilution plating procedure and advanced molecular biology technology(the high-throughput sequencing technology and the fluorescence quantitative polymerase chain reaction)to discuss the changes of basic physical and chemical characters of phosphorus,the alkaline phosphatase activities,the abundance of phosphate solubilizing bacteria,microbial community composition and polyphosphate kinase expression under different hydrostatic pressure.The main results as follows:(1)Microorganisms effect the cycle and transformation of phosphorus in polyphase interfacial under hydrostatic pressure,which research result shows that soluble phosphate and total phosphorus presents non-sterile high above sterile in the overlying water,Meanwhile,total phosphorus presents sterile high above non-sterile in sediments.The cycle and transformations of phosphorus are mainly participated by microorganisms.Phosphorus which released from sediments into the overlying water,soluble phosphate and total phosphorus is significantly higher atmospheric pressure,results in the total phosphorus is the highest under atmospheric pressurem and it is decreased with hydrostatic pressure increasing in sediments.It proves that hydrostatic pressure promotes phosphorus transportation and transformation from sediments to the overlying water in the range of 0.1 to 1.0MPa hydrostatic pressure.Through correlation analysis reconfirms that internal phosphorus release is influenced by multiple environmental factors.Thereinto,hydrostatic pressure plays an important role in cycling and transforming of phosphorus.(2)Effects of hydrostatic pressure on the alkaline phosphatase activities and theabundance of phosphate solubilizing bacteria at the water-sediment interface,which research result shows high hydrostatic pressure can significantly enhanced the alkaline phosphatase activities.Compared with the amounts of phosphate solubilizing bacteria in the sediment under atmospheric pressure,the amounts of phosphate solubilizing bacteria increases in the sediment between 0.2 MPa and 1.0 MPa hydrostatic pressure,especially,there are distinctly difference in the amounts of organic phosphate solubilizing bacteria under different hydrostatic pressure.By determining the phosphate solubilizing capacity of phosphate solubilizing bacteria,found that the phosphate solubilizing capacity of phosphate solubilizing bacteria obviously under high hydrostatic pressure exceeds it which is under atmospheric pressure in the range of 0.1 ~1.0 MPa hydrostatic pressure.We can draw a conclusion from correlation: inorganic phosphate solubilizing bacteria that are widely propagated leaded to increase phosphate solubilizing capacity.However,the phosphate solubilizing capacity of organic phosphate solubilizing bacteria depend on alkaline phosphatase hydrolysis.(3)Effects of hydrostatic pressure on microbial community composition and polyphosphate kinase at the water-sediment interface,which research result shows that average groups of microorganism which have taxonomic significance at order family genus and species level and the diversity of microbial community increase with hydrostatic pressure increasing in the sediments.Proteobacteria are main microorganisms,the next are Bacteroidetes,Chloroflexi,Actinobacteria and so on which are common bacteria of aquatic ecosystem in Heihe Jinpen Reservoir.The hydrostatic pressure makes relative abundance of some bacteria change regularly,for example,Actinobacteria Bacteroidetes and Verrucomicrobi show regularity which have taxonomic significance at phylum level,there are corresponding correlations between those and hydrostatic pressure;Deltaproteobacteria are increase and Epsilonproteobacteria are decrease with hydrostatic pressure increasing,and so on.Polyphosphate kinase gene express in sediments under different hydrostatic pressure,the expression quantity of polyphosphate kinase from high to low is:0.2MPa,0.5MPa,1.0MPa,atmospheric pressure.