the aquatic macrophytes weaken the positive interaction of algae triggered by the pollution. These
plants even transform positive interaction to negative one (Fig. 2 e C1). In the culture of blue and green algae, the aquatic
macrophytes enhanced the negative interaction. C. pyrenoidosa was affected more significantly by the plants than M. aeruginosa
(Fig. 2 e C2). Similarly, for the combination of both green algae C. pyrenoidosa and S. obliquus, these aquatic
macrophytes enhance their competitive effects in the unpolluted condition, and weaken their positive interaction in
the pollution conditions. Moreover, effect on algal interaction increased with the number of the macrophyte species
(Fig. 2 e C3)