Fig. 2

Metatranscriptomic analysis and environmental relationships of genes pertaining to phosphonate metabolism and methane production. A Standardized abundance profile (z score) for each functional gene. B Network analysis between each selected cluster of function and environmental parameter based on Spearman’s correlations. A connection indicates a strong (Spearman’s |r|>0.5) and significant (false discovery rate-corrected p<0.01) correlation. The thickness of a connection between two nodes represents the value of Spearman’s coefficient. Solid lines indicate positive correlations; dotted lines indicate negative correlations. The color of each node represents a specific category: gray = environmental parameter; purple = genes pertaining to methane metabolism; pink = phosphonate biosynthesis related genes; light green = genes from the C-P lyase gene cluster; dark green = other phosphonate catabolism-related genes; blue = phosphate response genes. C Taxonomic constitution and expression values of identified phnJ genes across the sampling period