To better understand the confounding role of beam-induced radiolysis on correlated nonmonotonic fluctuations in Bragg reflections, we acquired dose series of stationary crystals at cryogenic temperatures. Crystals dry mounted on TEM grids were cooled to ~100K preceding data collection. Supplementary Figure illustrates patterns of intensity decay for representative crystals of biotin (A-B), Zn(II)-methionine (C-D), Zn(II)-histidine (E-F), and Co(II)-porphyrin (G-H) (Supplementary figures 13 through 16 show this, and correlated fluctuations in reflection intensities, for additional crystals of each type, interrogated under the same conditions). Crystals that had shown anomalous correlated changes in Bragg reflections when illuminated at room temperature, showed similar changes at 100 K, albeit to a milder extent than their roomtemperature counterparts. However, the duration of anomalous intensity changes was generally more extended at 100K, past the first 1.0 e -/Å 2 of beam exposure (Fig ).