The Features of Production Processes in the Lakes of the Valaam Archipelago

Abstract

The paper reports the characteristics of primary production and destruction processes in small lakes of the Valaam archipelago. The study was carried out on 11 small lakes where the natural regime of functioning is preserved. Studied lakes have different origins, morphometric and hydrochemical parameters. Investigated lakes were characterized by high concentrations of nutrients, especially in the bottom layers. Structure of phytoplankton community differed between lakes. In total, 306 species of phytoplankton had been found in the lakes of the Valaam archipelago. The highest species richness was registered for green algae, diatoms, euglenids and cyanoprokaryota. The lakes of the Valaam archipelago differed in species composition, ratio of taxonomic groups, phytoplankton abundance and biomass. Abundance of phytoplankton and biomass varied from 0.1 to 676.6 million cells/l and from 0.1 to 105.2 mg/ l, accordingly. A wide range of photosynthetic rate (from 0.0 to 4.3 mgO2/ l day and destruction (from 0.0 to 4.2 mgO2/l day) had been shown for all studied lakes. High values of the maximum primary production (Amax) were typical for Igumenskoe, Leschevoe, Krestovoe and Vitalevskoe Lakes, low values were recorded in lakes Simnyahovskoe, Antonievskoe and Nikonovskoe. Mean values Amax (1.14 ± 0.08 mgO2/l day) and maximum destruction Rmax (1.19 ± 0.07 mgO2/l day) were high in all the lakes. In most cases (90%), the maximum photosynthesis rate was registered in the water layer from a surface down to a lower border of the Secchi depth. Data on chlorophyll α content in small lakes of the Valaam archipelago are provided for the first time. It was shown that most of the lakes are mesotrophic with signs of eutrophia (TSI 50–68).