The mutual influence between corrosion and the surrounding soil microbial communities of buried petroleum pipelines

Buried petroleum pipeline corrosion and leaks cause inevitable changes in the microbial communities of the surrounding soils. In addition, soils with different microbial communities can make different contributions to buried pipeline corrosion. Three kinds of soil samples of buried petroleum pipelines under different corrosion and petroleum contamination conditions were collected from the Shengli Oilfield of China to investigate the mutual influence between corrosion and the microbial communities of the surrounding soil. The 16S rRNA gene high-throughput Illumina MiSeq sequencing was used to analyze the microbial communities of different surrounding soils. Electrochemical tests were performed for steel corrosion investigation. The results showed that the microbial diversity of the surrounding soils of corroded pipelines with/without petroleum contamination (O-soil and C-soil, respectively) decreased significantly as compared with that of the non-corroded and non-contaminated ones (NC-soil). The C-soil contained more abundant Balneolaceae (Balneola, KSA1), Flavobacteriaceae (Muricauda, Gramella) and Desulfuromonadaceae (Pelobacter, Geoalkalibacter). The O-soil possessed a greater abundance of Halomonas, Pseudoalteromonas, Psychrobacter and Dietzia, which were reported to have a capacity for hydrocarbon degradation. Moreover, electrochemical measurements indicated that the microcosm of the C-soil and NC-soil promoted steel corrosion, while the C-soil community showed a slightly higher corrosion rate. However, the O-soil community mitigated the steel corrosion. These observations suggested that pipeline corrosion increased proportions of microorganisms, which are likely related to fermentation, sulfur respiration, iron respiration and manganese respiration in surrounding soils and enhanced the soil corrosivity, while petroleum contamination weakened the corrosion ability and promoted the growth of hydrocarbon-degrading organisms in the microbial community.