Relationship between nitrogen transformation and its related genes: comparison among riparian, marsh, and full-scale constructed wetlands

AbstractWetlands are known as effective ways for nitrogen pollutants removal. Three types of wetlands (riparian, marsh, and full-scale constructed wetlands (CWs)) were investigated in this study. Research endeavor was focused on: (1) the abundances and distribution of functional microbes in different kinds of wetlands, and (2) the relationship between nitrogen transformation and its related genes. Results from incubation experiments showed that the topsoil (0–20 cm) of riparian wetlands was more efficient for reducing ammonium, with a rate of 1.50 μg g−1 h−1, than the subsurface (20–40 cm). It was also found that full-scale CWs performed most effectively for the removal of nitrite (1.14/1.13 μg g−1 h−1) and nitrate (3.77/3.44 μg g−1 h−1). According to quantitative real-time PCR and principal component analysis, the highest -N transformation rate in the topsoil (0–20 cm) of riparian wetlands can be mainly attributed to the amoA and Nitrospira 16S rRNA genes. The similar transformation rates between two dep...