Content of photosynthetic pigments in Phragmites communis (Cav.) Trin. ex Steud., Salvinia natans L. (All.), Utricularia vulgaris L. and Ceratophyllum demersum L. during the season in the area of the Bardača pond (Republika Srpska)

It is known that aquatic macrophytes are an important part of freshwater ecosystems, and that they play a different role in their structure and functioning. Their presence and distribution depends on water temperature and transparency, nutrient content, conductivity, pH, chemical composition and water circulation. Therefore, the goal of our research was to determine the influence and interrelationship of physicochemical parameters of water on the content of photosynthetic pigments in aquatic macrophytes of Lake Necik, in the Ramsar area of Bardača (Republic of Srpska). Content of total chlorophyll (a + b) during the growing season (June–October) ranged from 0.231 to 1.145 mg g−1 FW in Phragmites communis Trin. ex Steud., from 0.061 to 0.541 mg g−1 FW in Salvinia natans L. (All.), from 0.063 to 0.626 mg g−1 FW in Utricularia vulgaris L. and from 0.063 to 0.443 mg g−1 FW in Ceratophyllum demersum L. Research has shown that floating and submerged macrophytes have a lower ratio of chlorophyll a/b compared to emergent hydrophytes, which is most likely the result of stress caused by increased light intensity and temperature. Seasonal variations in the content of photosynthetic pigments indicated that the species Phragmites communis proved to be more tolerant to the stress caused by the influence of various abiotic factors, while Salvinia natans proved to be more sensitive. Spearmon’s correlation coefficient of the physicochemical parameters of water and the concentration of photosynthetic pigments of macrophytes showed a significant influence of certain abiotic factors (temperature, transparency and nutrients) on the content of pigments in the leaves of Phragmites communis, Salvinia natans, Utricularia vulgaris and Ceratophyllum demersum L