Fig. 4: Silicon metabolism-related parameters for diatom taxa obtained using PDMPO.

Box plots of (A) new frustule surface area (µm² cell⁻¹ d⁻¹), (B) bSi production (pmol Si cell⁻¹ d⁻¹), and (C) degree of silicification (fmol Si µm⁻²) in control (Ctrl; dark gray), +Fe (light gray), and +DFB (white) treatments at 72 h for Thalassiosira (all centric diatoms not including Chaetoceros), Chaetoceros, and Pseudo-nitzschia (45 and 90 µm size groups). The center line represents the median and the boxes display the upper and lower quartiles with whiskers extending 1.5 times the interquartile range. Open diamonds show the arithmetic mean of a given sample. Black dots represent data from individual cells. Samples with <5 cells imaged were excluded and denoted nd. Significance was determined within each taxonomic group by Welch two-sample t test when comparing between two treatments or one-way ANOVA and Tukey’s HSD post hoc test when comparing among three treatments. Different lowercase letters delineate the statistically significant different groups within a taxa (p < 0.05). The vertical axes are plotted on a logarithmic (log₁₀) scale. Statistical test results and significance are shown in Table S5.