Figure 1.

(a) Chlorophyll-a concentrations (μg L⁻¹) in the top 2 mL (top light grey bars) and bottom 2 mL (lower dark grey bars) of 100 mL P. rubescens suspensions from De Kuil incubated for 1 h in the absence or presence of different concentrations ballast (50, 100, and 200 mg lanthanum modified bentonite (LMB) L⁻¹) combined with the flocculent polyaluminium chloride (PAC) (2 mg Al L⁻¹). Also included are the Photosystem II efficiencies (PSII) of the cyanobacteria collected at the surface of the tubes (filled circles) and at the bottom (open circles). Error bars indicate 1 standard deviation (SD, n = 3). Similar letters indicate homogeneous groups that are not different at the p < 0.05 level. (b) Similar to the panel (a), but now after 24 h incubation.