Sediment Fungal Communities of Constructed Wetlands Dominated by Zizania latifolia and Phragmites communis and Their Effect on Organic Pollutant Removal

Abstract

The purpose of the study was to investigate the relationship between wetland plants and fungal communities with a focus on their combined functions to remove organic pollutants. Two constructed wetland (CW) systems, covering a total area of 4.24 hm2, were established to treat the agricultural non-point source pollution using, respectively, Zizania latifolia (CW1) and Phragmites communis (CW2) as the dominant plant species. The obtained results showed that CW1 performed much better than CW2 in terms of promoting the abundance and diversity of the sediment fungal community identified by high-throughput sequencing technology. The enhanced fungal activity was shown to be one of the main factors that raised the pollutant removal rates and reduced the contents of the target pollutants (COD, TN, TP and NH4+-N) to levels below the stipulated national standards. Significant differences in abundant fungi were observed between the CW units and their inlet and outlet sampling sites, indicating that the plant species and pollutant concentrations were the key factors affecting the diversity and activity of the sediment fungal community. The findings of the study provided not only a better understanding of the plant–fungi symbiotic system but also useful information for the development of CW technology.