Fig. 1

Summary of the sample generation, sample preparation and data analysis of this study. Samples were retrieved from soils (a), generated from fresh polymers by treatment with UV radiation (b), or from incubating fresh polymers from one year in the soil under controlled lab conditions (c). Sample preparation for STXM-NEXAFS analysis. The polymer was glued on a block and microtomed in thin sections (d). The sections were deposited on Si₃N₄ membranes for STXM analysis (e). NEXAFS stacks were acquired on the edge of the section (f). The light blue part corresponds to the area outside the polymer thin section, while the dark blue part corresponds to the edge of the polymer thin section. For data analysis the spectra were background corrected and normalized (g), analysed by hierarchical cluster analysis to identify changes of the spectra over depth (h) and finally the spectra of the different clusters were displayed (i)