Graph showing paired connections for pigment content (а: chlorophyll a, k: carotenoids), nitrate concentration and abiotic variables (t: air temperature; l: water level; f: total precipitation; K_w: water exchange coefficient). (A): system of connections for pigment content; (B): system of connections for precipitation levels and hydrological variables. Line thickness indicates connection strength. The graph was plotted using only those connections that have statistically significant Pearson's correlation coefficients of more than 0.60 (shown above the lines).