Fig. 3: Microscopy images of microaggregates and attached bacteria.

Epifluorescence microscopy images of axenic Minutocellus polymorphus (a, b) and co-cultures of M. polymorphus and Marinobacter adhaerens HP15 (c, d), Vibrio thalassae (e, f), and Pseudoalteromonas carrageenovora (g, h) under blue (a, c, e, g) and UV (b, d, f, h) excitation wavelengths. Images were taken during the exponential phases of growth. Red: chlorophyll-a autofluorescence, blue: DAPI-bound nucleic acids. White arrows: diatom-attached bacteria; blue arrows: bacterial aggregates. Amorphous material is considered TEP.