Ecological aspects of mass development of Gonyostomum semen (Ehr.) Dies. (Raphidophyta)

Abstract

Mass development of Gonyostomum semen (Ehr.) Dies. (Raphidophyta) registered in a small slightly mineralized, slightly acidic, polyhumic, and eutrophic forest lake (Krivoye) located on the northern coast of the Rybinsk reservoir within the territory of the State Darwin reserve (Vologda region, Russia) is described. Some morphological characteristics and quantitative indices of the development of G. semen, and also biotic and hydrochemical parameters of the aquatic medium, are presented. Possible reasons of water "bloom" caused by Raphidophyta are discussed. It has been found that the abundance of G. semen is conditioned by a low content of calcium, low values of pH, intensive color of waters and their high trophic level.