Figure 5.

(a) Spearman correlation coefficients of relative abundance of bacterial families with assay measurements of cell biomass (SGI) and cell death (PI), redox activity (DCPIP), and esterase activity (FDL). Only bacterial families with > 0.5% abundance are shown. Red (Spearman’s ρ = 1) indicates a positive and blue (Spearman’s ρ = –1) indicates a negative correlation between assay data and taxa abundance. Prevalence (Prev.) of each family is plotted, indicating the proportion of samples in which that family was found. Abundance (Abun.) shows a bar plot of the proportion of sequencing reads matching taxa from that family across all samples. (b) Scatterplots show the relationship between log2 fold change from DESeq2 differential abundance analysis and the corresponding Spearman correlation coefficient (ρ) between each bacterial family’s relative abundance and the indicated assay variable (SGI, PI, DCPIP, or FDL). Each point represents a bacterial family colored by its phylum-level taxonomy, with panels faceted by compound (rows: DEHT and Tetradecane) and assay (columns). Dashed lines mark zero values for log2 fold change and correlation, while solid black lines indicate linear regression fits. R² values in each panel represent the proportion of variance in correlation explained by log2 fold change. This figure illustrates how taxonomic responses to hydrocarbon exposure relate to functional assay responses across microbial families.