Soil Physico-Chemical Properties And Bacterial Diversity In Daqing Oil Contatminated Soil

With the accelerated development of social industrialization process, the demand for oil is becoming more and more higher while the pollution of oil or its derivatives increasing seriously. The petroleum pollutants entered into soil, which results high pressure for self-healing of oil contaminated soil and would influence plant growth and harm for human health. Soil microorganism could adjust energy flow and cycle of matter in soil ecosystem by digest animal, plant and oil residues, and this function plays a pivotal role in growth and development. Therefore, in this work, we stuied different types of soil in Daqing district, expecially the oil contamintated soil, including physical and chemical properties, micro community structure and soil microbial diversity, which laid a foundation for bioremediation of petroleum contaminated soil in the future.Soil around the oil well in Daqing district as the object of study, farmland, forest land and zonal alkali soil as control, nine different locations soil were collected for comparethe difference of physicochemical property. The results as followed:a significant difference between moisture content in all soil samples:forest land has the highest water content, and farmland and forest land are fenerally higher than that of alkali and oil soil:no significant difference about pH value among samples; a highly significant difference in the electrical conductivity of soil among samples, and conductivity in oil contaminated soil was obviously higher than that of farmland and forest land. The correlation analysis between soil physical and chemical preoerties showed that pH and conductivity had a significant positive correlation (r=0.963**). In different enzyme activity determination test, phosphatase activity in farmland was the highest, and in alkali soil was the lowest:polyphenol oxidase activity in oil pollution was the highest, the lowest existed in oil well soil; the activity of sucrase in farmland and oil pollution soil was the highest, and the lowest was in alkali soil, and the same tendancy was in fluorescein diacetate esterase. The correlation analysis between soil physico-chemical properties and enzyme activity showed that phosphatase and fluorescein diacetate esterase had a significant positive correlation (r=0.97**). in polyphenol oxidase and conductivity (r=0.677**), but no significant correlation found among five enzymes. Soil microbial count results suggested that three types of bacteria in samples had a significant difference, bacteria was much higher in soybean farmland that that in oil well; fungi was generally higher in farmland and forest land than that in oil soil:alkali soil had more actinomycetes that oil well. In all soil samples, the total number of bacteria was about93.3%～99.36%. followed by actinomycetes (0.54%-6.44%), fungi (less than1%). With the Roche454(GS FLX Titanium System) high-throughput sequencing system, we compared the genetic diversity of16S rRNA in nine different kinds of soil samples, and the results suggested that Actinobacteria (22.92%～80.62%), Proteobacteria (3.3%～36.71%), Acidobacteria (0.38%～18.53%), Chloroflexi (1.55%～9.124%), Verrucomicrobia (0-0.84%), Planctomycetes (1.69%～8.42%), Nitrospirae (0.22%～1.76%), Bacteroidetes (0.51%～7.5%) and Gemmatimonadetes (0.8%～9.6%) were dominant bacterial phylum in all samples with more than90%in the total bacteria content. The relative abundance of bacterial class was significant or extremely significant correlation with soil moisture content. pH valum and conductivity. According to the distribution of bacteria and based on genus level, nine different soil were clustered into three groups, alkali spot1and2were grouped together (G1),60and70centuries oil well were togethered in G2, and the other five samples clustered into the same group (G3). Nitriliruptoria was the dominant bacterial class in the two alkali soil samples with the relative abundance of39.45%and32.64%, respectively. Nocardioides, Pseudomonas and Sphingomonas were the dominant bacterial class in other seven samples, which were aerobic bacteria and involved in biodegradation process.