Fig. 2

Schematic map of sampling sites and profiles of microbial communities. a The locations of Haima, Site F, and Haiyang 4 cold seeps, constructed with GeoMapApp (www.geomapapp.org). In our sampled cold seep site (CS), gas bubbles were found at the center of a dense mussel bed. At the CS site, sediment was evenly divided into four layers, meanwhile the non-seep (NS) site was collected from the adjacent non-cold seep background. Each layer had five replicates. b The abundance of genes implicated in methane, sulfur, and nitrogen cycles at the non-seep and five cold seep sites. Each row represents a gene and each column represents a sampling layer. For each gene, the total abundance of all samples was logarithmically transformed and shown on the right side (white-green block). The respective abundances of samples were logarithmically transformed and scaled by row (blue-red block). The depths of samples are shown on the top (white-purple block). c Mantel test between environmental factors and SSU rRNA gene. Red curves indicate significant correlations (p < 0.05), while gray curves indicate insignificant correlations (p > 0.05), and the line width represents the r statistic of the Mantel test. Pairwise comparisons of environmental factors were conducted and shown in the heat map. The color gradients and size of the squares represent Pearson correlation coefficients. d The stacked bar chart at the phylum level, based on annotations and respective abundance of SSU rRNA gene sequence clusters