Fig. 2: Microbial community diversity, composition, and assembly processes.

The box plot (A) illustrates differences in α-diversity (ACE and Shannon) indices of benthic microorganisms between Pre-COVID and Post-COVID periods, while PCoA (B) visualizes bacterial community β-diversity. Bray-Curtis dissimilarity (BCD) analysis is shown in boxplots (C), and the relative richness of dominant bacterial phyla at the seepage surface is displayed (D). A Venn diagram (E) highlights shared and unique ASVs between the two periods, and a box plot (F) compares the relative abundance of core ASVs. Phylogenetic and taxonomic turnover distributions, based on βNTI and RCbray values, are presented (G), followed by the proportions of assembly processes across Pre and Post-COVID periods (H). Significance levels: *P < 0.05, **P < 0.01, ***P < 0.001.