Box-and-whiskers plot of the number of attached bacteria cells per frustule or capsule in xenic A. minutissimum biofilms incubated for 11 to 31 days.

Bacteria were counted in SEM images, if they were in direct, visible contact with the valve face of either a frustule or a completely encapsulated diatom cell (see figures 2B and 3A for illustration). 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.