Fig. 4.

Minidiscus spp. in light microscopy. The dominating nano-sized Minidiscus centric diatoms (2–5 µm diameter) seen in light microscopy at station 74 (5.8 million cells L⁻¹) showing the impossibility of identifying it with the latter technique, while it remains possible to count it and compare with parallel SEM identification. The yellow Lugol stain background was removed using the camera’s autowhite function. The scale bar is 10 µm