Distribution of the number of bacteria cells adherent to diatom valve faces of different surface types (frustule or capsule) in xenic A. minutissimum biofilms.

Bacteria were counted in SEM images, if they were in direct, visible contact with the valve face of either a frustule (N = 54) or a completely encapsulated diatom cell (N = 71; see figures 2B and 3A for illustration). Samples were taken from 11 to 31 days old cultures. Boxes represent 1st and 3rd quartile. Black center lines represent medians. Whiskers extend to 1.5-fold of the inter-quartile range. Diamond symbols represent means. Black dots are outliers.