Figure 2

Microbial diversity analysis. (a) Simpson diversity index as a measurement of alpha diversity. An ANOVA test and a LSD (Least Square Difference) test were conducted (a–c indicate significance groups). (b) Redundancy analysis (RDA). Dots and triangles correspond with each sample on the first or second sampling year, respectively. Black points stand for the centroid of the first and second sampling year. Colour is indicative of the temperature gradient, and lines show the physical-chemical factors constrained into the ordination. (c) pairs between predicted functional groups (Supplementary Table S2), and physical-chemical factors. Dark blue indicates stronger positive correlations and dark red stronger negative correlations. Asterisks denote the significance levels (***p < 0.001, **p < 0.01 and *p < 0.05). P values were adjusted for multiple testing using the Bonferroni correction.