Bacterial structure and spatiotemporal distribution in a horizontal subsurface flow constructed wetland

Area of Science:

• Environmental Microbiology
• Wetland Ecology
• Molecular Biology

Background:

• Constructed wetlands (CWs) are engineered systems that mimic natural wetlands for wastewater treatment.
• Horizontal subsurface flow constructed wetlands (HSF-CWs) are effective in removing pollutants but require understanding of their microbial communities.
• The bacterial community structure is crucial for the efficiency of nitrogen removal processes in HSF-CWs.

Purpose of the Study:

• To investigate the bacterial community structure in HSF-CWs planted with Phragmites australis.
• To compare bacterial diversity between the rhizosphere (RH) and deep-layer (DL) zones.
• To identify key bacterial groups involved in nitrogen cycling and removal.

Main Methods:

• 16S rRNA gene cloning and sequencing technique was employed.
• Bacteria-specific primers (008F and 1492R) were used for gene amplification.
• Six clone libraries were constructed and analyzed, totaling 1,284 sequences.

Main Results:

• Proteobacteria were the dominant phylum (41.57% in RH, 42.17% in DL).
• Bacteroidetes, Planctomycetes, and Chloroflexi were other major groups.
• Deltaproteobacteria and Gammaproteobacteria subclasses were predominant in RH and DL, respectively.

Conclusions:

• Archaea and Bacteria in HSF-CWs are essential for the nitrogen cycle.
• The microbial community structure identified is efficient in removing nitrogen from wastewater.
• Understanding bacterial communities can optimize HSF-CW performance for wastewater treatment.