Spatio-temporal shifts in the archaeal community of a constructed wetland treating river water.

The distribution of archaeal community and the associated environmental variables in constructed wetland (CW), especially in free water surface flow CW (FWSF-CW), remain poorly understood. The present study explored the spatial and temporal dynamics of archaeal community in an FWSF-CW used for surface water treatment and evaluated the driving environmental variables. The archaeal density varied considerably among sites and seasons, ranging from 3.37×108 to 3.59×109 16S rRNA gene copies per gram dry sediment/soil. The archaeal population density was adversely affected by high temperatures and tended to be lower during summer than during spring and winter. Moreover, considerable spatio-temporal variations of archaeal richness, diversity and community structure also occurred in the FWSF-CW. Higher nutrient contents correlated with a lower archaeal richness and diversity. Nitrate and carbon/nitrogen ratio were found to play important roles in shaping the overall archaeal community structure. Euryarchaeota and Bathyarchaeota were the dominant archaeal phyla in wetland sediments, while Thaumarchaeota tended to be dominant in wetland soils. In addition, the wetland archaeal community was related to vegetation type.