Additional file 2 of Increased microbial sequestration of soil organic carbon under nitrogen deposition over China’s terrestrial ecosystems
Creators: name: Liao, Shu
name: Tan, Siyi
name: Peng, Yan
name: Wang, Dingyi
name: Ni, Xiangyin
name: Yue, Kai
name: Wu, Fuzhong
name: Yang, Yusheng
Publisher: name: figshare
Year: 2020
Subjects: subject: Microbiology
subject: FOS: Biological sciences

description: Additional file 2. Text S1. Supplementary notes for data compilation. Figure S1 Concentrations of amino sugar biomarkers plotted against microbial necromass C. (a) Total amino sugars versus total microbial necromass C, (b) glucosamine versus fungal necromass C, (c) muramic acid versus bacterial necromass C. All data were collected at the control plots without N addition. Pearson’s r and P values from linear regressions are shown in each panel. Figure S2 Differences in the effect sizes of N addition on (a) total microbial, (b) fungal, and (c) bacterial necromass C before and after the data that were calculated by amino sugar biomarkers were included in our dataset. The red boxes show the data that were obtained directly from the articles (n=13, 8, and 8 for panels a, b and c, respectively). The blue boxes show the data that were obtained directly from the articles plus the data that were calculated by corresponding amino sugar biomarkers (all n=118). Fungal and bacterial necromass C were calculated by glucosamine and muramic acid biomarkers, respectively. The individual effect sizes were used for comparison in this analysis. The significant differences were tested by Wilcoxon rank-sum test due to the unequal sample sizes. Figure S3 Differences in the influence of N addition on (a, d) total microbial, (b, e) fungal, and (c, f) bacterial necromass C between forest (red; n=14) and cropland (blue; n=103). The individual effect sizes (above) and percent changes (below) were used for comparison in this analysis. The sample size was only 1 for grassland, which was not included in this analysis. The significant differences were tested by Wilcoxon rank-sum test due to the unequal sample sizes. Given that percent changes were calculated by individual effect sizes (see Response Metrics), the P values were the same for the differences in individual effect sizes and percent changes. Figure S4 Frequency distribution of the effect sizes for (a–c) amino sugars and (d–f) microbial necromass C in response to N addition. The solid curves are Gaussian distributions fitted to the frequency data, and the vertical dotted lines are drawn at effect sizes of zero. Sample sizes and P values of the normal distribution test are shown in each panel. Figure S5 Concentrations of (a–c) amino sugars and (d–f) microbial necromass C at control versus N addition plots. Error bars represent the variances of individual effect sizes calculated by means, standard deviations, and sample sizes for controls and N addition on both the X- and Y-axes. The dotted blue lines show 1:1 lines. Adjusted R2 and P values from linear regressions for testing the relationships between the control and N addition plots are shown at the top of each panel, and sample sizes and p values from Bray-Curtis analyses for comparing the differences between the control and N addition plots are shown at the bottom of each panel. Figure S6 Percent changes in amino sugars under different magnitudes (upper) and durations (lower) of N addition. (a, d) Total amino sugars, (b, e) glucosamine, (c, f) muramic acid. Error bars represent the 95% bootstrap confidence intervals that were calculated by weighted effect sizes. The between-group heterogeneities (Qb) and the probabilities (P) of the effects of N addition on amino sugars across different magnitudes and durations are shown in each panel. The vertical dotted lines are drawn at percent changes of zero. The responses of these variables to different magnitudes and durations of N addition are considered significant (P&lt;0.05) if the 95% bootstrap confidence intervals do not overlap with zero. Table S1 The study sites at which microbial necromass C was measured under N addition. Table S2 Soil biogeochemical properties at the study sites at which microbial necromass C was measured under N addition. Table S3 The hydrolysis conditions used to determine the concentrations of amino sugars in soils. Table S4 Total and between-group heterogeneities (Q) and probabilities (P) of the effects of N addition on amino sugar biomarkers and microbial necromass C. Table S5 Individual effect sizes for soil microbial necromass C in response to N addition. Table S6 Individual effect sizes for soil microbial biomass C in response to N addition. Table S7 Weighted effect sizes and percent changes in microbial necromass C and biomass C under N addition. Table S8 Standardized coefficients of partial least square (PLS) regressions. Table S9 Estimates of changes in soil biogeochemical variables under N addition in meta-analyses.