Figure captions
Figure 1 Changes in the amoA gene abundance of AOA, AOB,
comammox Nitrospira clade A and clade B during N addition and N
cessation. Different letters denote significant differences among
treatments (P < 0.05).
Figure 2 Principal component analysis (PCA) patterns of
community compositions of AOA (a), AOB(b), comammox Nitrospira clade
A(c) and clade B(d) during N cessation. points are marked according to
fertilization treatments.
Figure 3 Whole co-occurrence network of AOA operational
taxonomic units (OTUs), AOB OTUs, and Nitrospira clade A OTUs and clade
B OTUs during N cessation. A summary of node statistics is provided to
bottom of the network.
Figure 4 Changes in net N mineralization rates and
nitrification rates during N cessation. Different letters mean
significant differences at P = 0.05 level under different treatments.
Figure 5 Structural equation model (SEM) analysis of the
effects of N addition (a) and N cessation (b) on AOB and nitrification.
Numbers at arrows are standardized path coefficients.
R2 values associated with response variables indicate
the proportion of variation explained by relationships with other
variables.
Figure 6 A conceptual framework of ecosystem nitrogen (N)
cycling processes to N addition (a) and N cessation (b) based on this
study.