This readme file describes the data file "Periphyton_Leys_et_al_MolEcol.txt" accompanying the above publication. For any further queries please contact marie.leys@gmail.com. - The table has 390 rows and 5 columns (excluding the column headers). - Each row correspond a single estimate of periphyton biomass on a specific stone (5 replicates per site and date), site and date. - Periphyton biomass was estimated following Uehlinger (1991). Uehlinger U (1991) Spatial and temporal variability of the periphyton biomass in a prealpine river (Necker, Switzerland). Archiv Für Hydrobiologie, 123, 219-237 - A describition is given for each column header: column 1 ("Stone_replicate"): identifier of the stone from 1 to 5. Five measurements were taken per site on a specific date, each measurement was taken on a different stone. column 2 ("Valley"): The glacieriezed basin where sampling was done. column 3 ("Site"): sampling sites column 5 ("Date"): date of periphyton filtering column 5 ("Periphyton"): estimate of periphyton biomass in mg.m-2 - Missing values are represented as NA. Measurement was not possible when the stream was ice or snow covered. - Additional information and spatial coordinates of the sampling sites are provided in the supplementary Table S2 of the associated publication.