Figure 3.

Elemental map analysis of a section of T. pseudonana.

Cross-sectional girdle band view of T. pseudonana with the corresponding (a) phosphorous, (b) oxygen, and (c) silicon elemental maps, overlaid on an SEM image (d). Differences in the field of view between the x-ray maps and the SEM image are due to the difference in the detector positions relative to the sample. As expected, silicon is concentrated within the cell walls. Phosphorous signals coincide with lipid-enriched portion of the cell. Oxygen signals are relatively high over the entire field of view but there are areas of enrichment, mainly along the cell wall