Typical MIP image and X–Y cross section of TPM tomograms of three living diatom cells. Cell No. 1: (a) MIP. (b) and (c) X–Y cross sections at depths of (b) 1.0 and (c) 2.0 μm from the cell surface. Cell no. 2: (d) MIP. (e) and (f) X–Y cross sections at depths of (e) 1.0 and (f) 2.0 μm from the cell surface. Cell no. 3: (g) MIP. (h) and (i) X–Y cross sections at depths of (h) 1.0 and (i) 2.0 depth. Scale bar = 2 μm.