Structure and functional genes associated with carbon, nitrogen, phosphorus, and sulfur cycling processes in periphyton: A comparison between natural and artificial rivers

Abstract Periphyton in aquatic ecosystems plays vital roles in the elemental cycle process and is vulnerable to anthropogenic interference. However, few studies have explored the elemental cycles of carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) in the natural and artificial rivers using functional genes and microbial interactions in periphyton. In this study, the DNA metabarcoding and the quantitative microbial element cycling smart chip were employed to investigate the differences in the microbial‐mediated CNPS cycling processes between the Feng and Zao Rivers, representing natural and artificial rivers, respectively. Compared with the more C‐fixation (7.55 × 10 4 ± 2.12 × 10 4 copies/ng) and nitrification (4.75 × 10 3 ± 2.95 × 10 3 copies/ng) gene abundance in the artificial river, the C‐degradation (2.98 × 10 4 ± 1.31 × 10 4 copies/ng), denitrification (3.62 × 10 4 ± 7.25 × 10 3 copies/ng), and S‐reduction (6.66 × 10 3 ± 4.26 × 10 3 copies/ng) gene abundance were more in the natural river. In the natural river, the low levels of TN (5.37 ± 0.40 mg/L), DO (3.27 ± 0.32 mg/L), NH 4 + (0.05 ± 0.05 mg/L), and NO 3 − (4.36 ± 0.88 mg/L) could support C‐degradation, denitrification, and S‐reduction. Conversely, higher NO 3 − levels (8.47 ± 2.13 mg/L) promoted nitrification in the artificial river. Moreover, more bacterial genera were involved in the CNPS cycling in the artificial river, whereas the bacterial‐algal relationship was more complex in the natural river. This study could provide insights into the biodiversity and ecological functions of periphyton in different river types.