Bacterial diversity dynamics in a long-term petroleum-contaminated soil.

Bacterial diversity dynamics were investigated in the soil samples in different distances and depths from/at a long-term petroleum-contaminated site. Microbial activity in the soil samples showed ATP values closely correlated with organic matter content (OC) and total petroleum hydrocarbon (TPH). Bacterial community diversity (H) and evenness (J) using PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and PCR-T-RFLP (terminal restriction fragment length polymorphism) results showed positive correlation with concentration of TPH or OC, but tmoA (toluene monooxygenase gene)-based bacterial H and J using a PCR-T-RFLP result did not. No significant difference of H and J values in the bacterial and the tmoA communities was observed. The bacterial community structure characterized by PCR-DGGE and PCR-T-RFLP techniques showed similarity according to soil sampling distance rather than soil sampling depth. Canonical correspondence analysis demonstrated that OC including TPH had the most significant effect on the bacterial community diversity at the long-term petroleum-contaminated site.