The Dynamics of Phytoplankton Pigment Characteristics of Lake Teletskoye

Abstract

Photosynthetic phytoplankton pigments were investigated in the surface layer of the pelagic zone of Lake Teletskoye during ice-free periods in 1998–2000. Pigment characteristics were also monitored at the lake outflow, the Biya River, from July 1998 till September 2001. Processes of lake phytoplankton development and functioning are closely represented at the river site, as are changes of pigment composition that follow dynamic regularities. On the basis of seasonal fluctuations of pigment concentrations, five phases in planctonic algal development were revealed. Comparisons of phytoplankton seasonal dynamics in this deep oligotrophic lake with those of different lake types of the temperate zone were considered. The trophic status of the pelagic zone and outflow at the Biya River indicated by chlorophyll a content corresponds to ultraoligotrophic–oligotrophic conditions. The relationship between green and yellow pigments classifies Lake Teletskoye with water bodies of “carotene” type. The low values of pigment index indicate an active physiological state of microalgae over the whole year. A weak linear relationship between chlorophyll a content and temperature, as well as lack of correlation with mineral nitrogen and silicon, testify to a complex interdependence resulting from synchronous effects of abiotic and biotic factors. The development of phytoplankton in the lake is limited by extremely low concentrations of dissolved reactive phosphorus and silicon.