Study of photosynthetic pigments in the hyperhaline Kuyalnik Estuary and its inflows (Ukraine, north-western Black sea region)

Purpose. To investigate the interannual and intraannual analysis of the content of chlorophyll "a", "b", "c" and pheophytin in the Kuyalnik estuary (KE) and its tides for the period 2008-2012, to evaluate the spatial distribution of chlorophyll "a" in the water area of the estuary in different seasons year and reveal the connection of the specified characteristics with the abiotic factors of the environment. Methods. Hydrochemical, biological and static analyses. The original geo-informational database of comprehensive monitoring of the KE basin was used. Results. According to the results of generalization, analysis and systematization of the experimental studies materials of the photosynthetic pigments content (chlorophylls ‘a’, ‘b’, ‘c’) and pheophytin (the primary product of chlorophyll decomposition) in the surface waters of the hyperhaline Kuyalnik Estuary (KE) and its main water inflows (Velykyi Kuyalnyk river, drainage channels from the Peresyp and Korsuntsivsky ponds) during the period of low water content in the estuary (2008-2012) the interannual and intraannual distribution of pigment content is presented, their ratio in the specified water bodies and the spatial distribution of chlorophyll "a" content in the water area of KE in different seasons of the year are evaluated. It has been revealed that in the periods of low water content in KE and high salinization of its waters production activity is insignificant, but it does not stop. Adaptive mechanisms of algal communities in relation to extreme conditions of KE (salinization, decreasing of water level and increase of water temperature, decreasing of freshwater inflow) are expressed in an increase in the share of auxiliary pigments (chlorophylls "b" and "c"). The obtained ratios of pigments indicate mainly the dominance of diatom algae in all water bodies of the basin during the research period. A correlation analysis of the relationships between the concentrations of chlorophylls "a", "b", "c", concentrations of different chlorophylls and pheophytin and between chlorophyll "a" and the main abiotic factors of the environment (temperature, pH, dissolved oxygen in water, BOD₅, COD, ammonium nitrogen and phosphorus phosphate) were carried out. Conclusions. The results of the study of the pigment fund Cl indicate that the characteristics of the content of photosynthetic pigments and their ratio can be used as integral characteristics of the productivity and ecological state of water bodies.