Figure 2.

The effect of black carbon on S. aureus biofilm structure. Biofilms of S. aureus SH1000 were cultured in the presence or absence of 30–100 μg/ml BC. Biofilms were imaged by scanning electron microscopy at increasing resolution (a–d) and light microscopy was used to quantify biofilm thickness (e.g., n = 18). Images are representative of the entire biofilm structure. Viable bacterial cells were measured by sequential removal and quantification of planktonic, loosely‐adhered, and biofilm bacteria (h, n = 4). Error bars represent ± 1 SEM. Significance was determined by t‐tests (g) or ANOVA (h) *=p ≤ 0.05, **=p ≤ 0.01, ***=p ≤ 0.001, ****=p ≤ 0.0001.