Pigment characteristics of algocenoses in small rivers of the northwestern coast of Lake Ladoga

Data on the spatial dynamics of the content of chlorophylls a, b and c, carotenoids and pigment indices of phytoplankton and periphyton in small rivers (tributaries of the western coast of Lake Ladoga) are presented. The chlorophyll a content of river phytoplankton varied from 1.8 to 49.8 mg/m3, in periphyton – from 8.5 to 262 µg/g of substrate, that corresponded to a mesotrophic status, and in some river parts – to a eutrophic status. The chlorophyll a content of phytoplankton decreased towards the river mouth in the Avloga and Vyun rivers, in the Morye river it increased downstream, and in the Sosnovka river it was distributed relatively evenly. The chlorophyll a content of periphyton increased downstream in the Avloga and Sosnovka rivers, while in the Morye and Vyun rivers it decreased. In the total of chlorophyll pigments in both algocenoses, chlorophyll a prevailed, its fraction being 56–96%. The ratios of additional pigments (chlorophyll b and c) indicated the predominance of green algae, diatoms, and euglenoid algae in the studied communities. In general, comparison of pigments and carotenoids has revealed favorable conditions for the functional activity of both phytoplankton and periphyton communities, that allows classifying the studied rivers as slightly polluted.