Research On Microbial Characteristics Of Oilfield Wetland Soil In The West Songnen Plain

Petroleum is the important energy around the world, however, itseriously pollutes the environment during the process of being exploited,transported and consumed. Studies on the impacts of petroleumcontamination on environment have been a research hotspot. Wetlands,which extend over vast areas in Songnen Plain, have great significancefor environment, ecology and economy. Among that, the western regionof Songnen Plain is the major rejoin of saline wetlands in our country,and with the improvement of oil development and other human activities,the area of wetlands is gradually shrinking and the salinization degree ismore and more serious. Therefore, the ecological destruction caused bypetroleum pollution in Songnen Plain needs to be urgently addressed.Microorganism has important significance for ecosystem, and it plays animportant role in degradation of pollutants, maintaining soil fertility andrestoring the ecological environment. In recent years, there have beenmany reports on the impacts of petroleum contamination onmicroorganism of wetland; however, there are few studies on themicrobial characteristics of higher salinity degree soil contaminated bypetroleum in wetlands. This study was aimed to analyse the characteristics of soilmicroorganism in marsh wetlands and wet meadow contaminated bypetroleum in the west Songnen Plain. The conventional plate culturemethod and Biolog Ecoplate were applied to investigate the changes inmicrobial quantity and metabolic function and reveal the influence ofpetroleum contamination on microbial community structure andmetabolic diversity. And by measuring the soil abiotic factors, wecompared the differences of soil physical and chemical propertiesbetween different degree petroleum pollution and studied the effects ofpetroleum on the physical and chemical properties of wetland soils. Inaddition, we compared the characteristics of microorganism insalina-alkalina meadow contaminated by different degree of oil pollutionto reveal the microbial adaptability to petroleum pollution.It was proved by field survey and sampling investigation that thewetland soils were polluted by petroleum to different degree in the westSongnen Plain. Soil organic matter content was positively related with thetotal petroleum hydrocarbons. The oil pollution had no significantinfluence on total phosphorus, pH, conductivity and water content ofwetland soils.The analysis of microbial community structure showed that thenumber of the bacteria was dominant, actinomycetes followed, andfungus was least in soil microorganism community structure of wetland soils in the west Songnen Plain. Microbial quantity of wet meadows washigher than marsh wetlands. There were different effects of petroleumcontamination on microbial quantity between the two types of wetlands.With the increase of total petroleum hydrocarbons, the number ofmicroorganism decreased in marsh wetlands, while increased in wetmeadows. There was certain correlation between the physical andchemical properties of wetland soils and microbial quantity.To reveal the impacts of the physical and chemical soil properties onmicrobial metabolic function, we found that microbial metabolic intensityof wetland soils in October was higher than that in May, and the types ofmicrobial carbon source utilization was changed by petroleum. With theincrease of total petroleum hydrocarbons, the ability of using polymerwas enhanced. The microbial metabolic intensity and diversity waspositively correlated with the soil organic matter content, and negativelycorrelated with soil pH. The total petroleum hydrocarbons enhanced themicrobial metabolic intensity in wet meadow soils.The bacteria were dominant in salina-alkalina meadow soils in westSongnen Plain, and a certain concentration of oil pollutants acceleratedthe growth of bacteria and improved the bacteria population. The longerthe soils were polluted, the stronger the adaptability of bacteria was topetroleum.