Fig. 4
From: UV radiation limited the expansion of cyanobacteria in early marine photic environments
UV-C attenuation in cell free, Fe(III)–Si-supplemented growth media. a Attenuation (% absorbance at 254 nm wavelengths) of UV-C radiation in unfiltered, cell-free growth medium supplemented with varying amounts of Si and Fe(III) (diamond: Fe(III) only; square: 0.6 mM Si; triangle: 2.0 mM Si). b UV-C attenuation in solutions that have been sequentially filtered to separate dissolved (<0.025 μm), nanoparticulate (0.025–0.22 μm), and colloidal (>0.22 μm) Fe(III)–Si fractions. Attenuation effects of the A+ medium have been subtracted. Error bars (if not shown than smaller than symbols) represent standard deviation at 2σ uncertainty
