Effect of media and heterotrophs on autotrophs and algicidal effect. Effect of media and heterotrophs on autotrophs, and algicidal effect of BUZ 2 on autotrophs; (a) White bars: autotroph in BG11 (white bar at day 0 is common starting cell density for all treatments), light gray bars: autotroph in the mixture of SM/BG11 (1:1), dark gray bars: autotroph in the presence of heterotrophic BUZ 2, black bars: autotroph in the presence of heterotrophic BUZ 3 in SM/BG11. Values represent the means from four to eight cell counts per treatment ± st. dev. Significant differences are indicated by different letter according to a P value of 0.05. (b) Algicidal effect of BUZ 2 on the autotroph calculated according to Jung et al (2008); white bars: algicidal effect compared to cyanobacterial culture in BG11, grey bars: algicidal effect compared to cyanobacterial culture in SM/BG11 mixture (1:1).