Microbial diversity in Huguangyan Maar Lake of China revealed by high–throughput sequencing

Huguangyan Maar Lake is a typical maar lake in the southeast of China. It is well preserved and not disturbed by anthropogenic activities. In this study, microbial community structures in sediment and water samples from Huguangyan Maar Lake were investigated using a high–throughput sequencing method. We found significant differences between the microbial community compositions of the water and the sediment. The sediment samples contained more diverse Bacteria and Archaea than did the water samples. Actinobacteria, Betaproteobacteria, Cyanobacteria, and Deltaproteobacteria predominated in the water samples while Deltaproteobacteria, Anaerolineae, Nitrospira, and Dehalococcoidia were the major bacterial groups in the sediment. As for Archaea, Woesearchaeota (DHVEG–6), unclassified Archaea, and Deep Sea Euryarchaeotic Group were detected at higher abundances in the water, whereas the Miscellaneous Crenarchaeotic Group, Thermoplasmata, and Methanomicrobia were significantly more abundant in the sediment. Interactions between Bacteria and Archaea were common in both the water column and the sediment. The concentrations of major nutrients (NO3−, PO43−, SiO32− and NH4+) shaped the microbial population structures in the water. At the higher phylogenetic levels including phylum and class, many of the dominant groups were those that were also abundant in other lakes; however, novel microbial populations (unclassified) were often seen at the lower phylogenetic levels. Our study lays a foundation for examining microbial biogeochemical cycling in sequestered lakes or reservoirs.