Fig 8. Biomass survival as a function of cell exposure duration, UV wave length, and the mineral type.

After three days of re-growth, cyanobacterial populations survived better when they were shielded by biotite and phlogopite than by muscovite, even though the muscovite thickness (0.177 mm) was greater than those of phlogopite and biotite (both at ~0.1 mm). Relative to UVB, exposure to UVC resulted in a lower survival rate. Likewise, longer exposure resulted in a lower survival rate. Unprotected cells were nearly completely killed in 24 hrs. Error bars indicate standard deviation from experimental duplicates.