groundwater, total petroleum hydrocarbons, microbial community structure, co-occurrence network, Environmental technology. Sanitary engineering, TD1-1066

In order to investigate the relationship between prokaryotic microbial communities and total petroleum hydrocarbon(TPH) contamination, high-throughput sequencing technology was used to investigate the microbial community structure in groundwater contaminated with petroleum hydrocarbons(TPH 0.01-2.09 mg/L). The results showed that the bacterial community was more sensitive to petroleum hydrocarbon contamination. At the phylum level, the largest relative abundance of archaea and bacteria were Euryarchaeota(34.63%-92.73%) and Proteobacteria(72.18%-83.34%), respectively. The abundances of Methanogens spp. in archaea and Acinetobacter, Rhodobacter, Pseudomonas, and Novosphingobium in bacteriain of the wells with high concentration petroleum hydrocarbons were significantly higher than that of other wells. Compared with archaea, bacterial community structure was more closely related to the tolerance of petroleum hydrocarbons. Other physical and chemical properties of groundwater, such as pH, sampling depth, ORP, temperature, and DO, also had impacts on community structure. The top 100 sequences with the highest abundance were selected from the archaeal operational taxonomic(OTU) group and bacterial amplicon sequence variant(ASV) group to construct a co-occurrence network. Through co-occurrence network analysis, three ecological modules related to petroleum hydrocarbon degradation processes were identified, and the relative abundance differences of the three modules were significantly related to TPH tolerance, with Euryarchaeota and Proteobacteria as the main members of the modules.