Characterization of substrate microbial communities in vertical flow mesocosms as impacted by both planting pattern and species richness

This study investigated the effects of three planting patterns and related plant species richness on the structure and metabolic activities of microbial communities in vertical flow mesocosms fed with piggery wastewater. The planting pattern impacted the microbial community composition in the current mesocosm substrates, with 17, 12 and 10 fatty acids occurring in the substrates of monocot (M), dicot (D) and M + D planting pattern, respectively. In contrast, the planting pattern did not impact fatty acid abundance and the utilization intensity of six carbon guilds. Plant species richness from each planting pattern differently impacted fatty acid methyl ester (FAME) profiles, i.e. greater M richness enhanced the abundance of 18:3ω6c (fungi), D richness simultaneously enhanced the abundance of both i15:0 (Gram-positive bacteria) and 18:1ω9c (Gram-negative bacteria) and M + D richness increased the abundance of 18:0 (Gram-positive bacteria), 18:1ω9c and 18:2ω6c (fungi), respectively. Similarly, greater M, D and M + D richness enhanced the utilization of the amino acid, polymer and carbohydrate guilds, respectively. Therefore, the current study highlights the importance of plant species richness in distinguishing the microbial community in constructed wetland (CW) systems.