Fig. 1

A 2-year microbial survey across three canyon-shaped reservoirs. A Maps of Klíčava (top), Žlutice (middle), and Římov (bottom) reservoirs. Sampling stations are indicated as open (epilimnion) and closed (hypolimnion) circles. The location of water inflows and dams are indicated by closed triangles and squares, respectively, outside the maps. The bold lines represent a scale of 1 km. B Comparison of the key environmental profiles. Each box plot includes all the samples collected during the study. The lower and upper edges of the boxplots correspond to the first and third quartiles, the whiskers extend to the largest or smallest value at 1.5 times the interquartile, and the black bars across the box represent median values. Dots that exist beyond one of the whiskers represent outliers. C Identification of four successional seasonal phases (spring, clear-water, summer, and fall/winter) at the lacustrine regions based on key environmental profiles from the year 2019 (data from the year 2018 is not included). K: Klíčava, Z: Žlutice, R: Římov, E: Epilimnion, H: Hypolimnion