Archaeal community structure along a gradient of petroleum contamination in saline-alkali soil

The response of archaeal communities to petroleum contamination in saline-alkali soil was characterized by analyses of three soil samples with different total petroleum hydrocarbon concentrations. Through the construction and screening of 16S rRNA gene clone libraries based on DNA extracts from these soils, nine distinct phylogenetic groups were identified. Statistical analyses showed that the distribution of archaeal community structures differ significantly along the gradient of petroleum contamination in these three saline-alkali soils. Five phylogenetic groups were dominant in the control soil, two of which were also abundant in the lightly contaminated soil. Four phylogenetic groups were dominant in heavily contaminated soil, one of which was also abundant in the lightly contaminated soil. The halophilic genus of Haloferax and the haloalkaliphilic genus of Natronomonas were more abundant in heavily contaminated soil. These results suggested that the genera of Haloferax and Natronomonas may have a role in the natural attenuation of petroleum-contaminated saline-alkali soil.