Fig. 6

Potential contribution of viruses to biogeochemical cycle in activated sludge (AS). A The glycoside hydrolases (GHs) encoded by AS viruses. The schematic shows the degradation of complex polysaccharides by different GHs encoded by AS viruses. The blue font indicates the classes of GHs. B Contribution of AS viruses to the sulfur (S) cycle. The schematic shows three pathways of the S cycle, including sulfur oxidation, assimilatory sulfate reduction, and dissimilatory sulfate reduction. Key genes in each pathway are indicated on the arrows with black font. AMGs carried by viruses are colored in brown. C Contribution of AS viruses to the nitrogen (N) cycle. The schematic shows the major pathways of the N cycle. The different arrow colors represent different pathways. Key genes in each pathway are indicated on the arrows with black font. AMGs carried by viruses are colored in green. D Contribution of AS viruses to the phosphorus (P) cycle. The schematic shows the pathways of organic phosphoester hydrolysis. Key genes in this pathway are indicated on the arrows in black font. AMGs carried by viruses are colored in gold