SEM images of associated diatom flora A, B Orthoseira circularis (Ehrenberg) R.M. Crawford C, D Eunotia cf. pseudominor Pavlov & Levkov E Humidophila contenta (Grunow) Lowe et al. F Hantzschia amphioxys (Ehrenberg) Grunow G, H Nitzschia brevissima Grunow I Pinnularia borealis Ehrenberg sensu lato J Pinnularia sp. Scale bars: 10 µm (A, B, D, F, H, I, J), 5 µm (C), 4 µm (E), 3 µm (G).