Figure 4.

Taxonomic distribution of microbial communities growing on plastic additives. (a) Heatmap of taxonomic family abundances for each combination of inocula and substrate (State2, NC = blue, tetradecane = yellow, DEHT = green), for each biological replicate (N = 3). Only families with > 0.5% abundance are shown and taxa were ordered using Bray–Curtis dissimilarity-based hierarchical seriation at the family level. Color intensity (white to dark gray) represents increasing relative abundance. (b) Volcano plots show log₂-fold changes in relative abundance for each family following enrichment on DEHT (left) or tetradecane (right) compared with the NC, as determined by DESeq2 analysis of family-level counts. Each point represents a bacterial family; red points indicate significantly differentially abundant families (adjusted P < .05), while grey points are nonsignificant. Horizontal dotted lines mark the significance threshold (adjusted P = .05), and vertical dashed lines indicate two-fold change boundaries (|log₂FC| = 1). (c) Top 20 families with the largest absolute fold changes for DEHT (green) and tetradecane (orange) enrichments vs NC. Shrunken log₂-fold changes (± SE) as calculated by DESeq2 are shown. Bars correspond to mean abundance shifts relative to the NC. All log₂FC values are significant (P < .001).