Fig. 5: Environmental and biotic features of the locations of mesocosm experiments M1, M2 and M3 and major effects of the supply of B12 and α-ribazole in the course of the experiments.

Treatment effects include changes in the composition of prokaryotic and eukaryotic communities and changes in transcription of genes encoding different proteins in Gammaproteobacteria (mainly SAR86 clade), Pelagibacteraceae and Prochlorococcus. -: decrease; +: increase. d1, d2, d3, d4, d6: day 1, 2, 3, 4 and 6; h3: hour 3. ++ or -- indicate strong changes. When no + or no – is given no significant change between a treatment and the control was detected. M3 was not analysed for metatranscriptomics (accentuated in grey). For further details and specific responses of individual lineages see Figs. 4 and 6 and Supplementary Figs. S5 and S7 to S12. For other abbreviations see text.