Factors of Dynamics of Plankton Crustacean Communities under Eutrophic Conditions

Russian Journal of Ecology - It has been shown that the main drivers of the dynamics of cladoceran and copepod abundances can be predators (fish), the quantity and/or quality of food in terms of...     

The use of bioluminescent biotests for study of natural and laboratory aquatic ecosystems

A set of bioluminescent tests was developed to monitor water quality in natural and laboratory ecosystems. It consisted of four bioluminescent systems: luminous bacteria, coupled enzyme system NADH:FMN-oxidoreductase-luciferase and triplet enzyme systems with alcohol dehydrogenase and trypsin. The set of biotests was applied for a small forest pond (Siberia, Russia), laboratory microecosystems polluted with benzoquinone and a batch culture of blue-green algae. Thereby effects of natural water compared to those of models of heavy pollution and “bloom” of blue-greens on the bioluminescent tests were revealed. The set of biotests was not affected by a natural seasonal variability of water quality in the unpolluted pond, but responded to the heavy pollution and the “bloom” of blue-greens. The set of biotests could be recommended as the alarm test to control the acute toxicity of natural water bodies.     

Allochthonous and Autochthonous Food Sources for Zoobenthos in a Forest Stream

Russian Journal of Ecology -     

Modelling the effect of planktivorous fish removal in a reservoir on the biomass of cyanobacteria

In 2002, a “top-down” biomanipulation (reduction of biomass of planktivorous fish Carassius auratus) had been successfully carried out in a small reservoir of the river Bugach (Krasnoyarsk, Russia), after which the cyanobacterial blooming ceased. However, the reservoir ecosystem was absolutely free of Daphnia – the main link of trophic cascade. As supposed, the reduction of blooming was the result of suppression of a direct stimulation effect of planktivorous fish on cyanobacteria, revealed earlier in laboratory experiments. The question arose as to whether the effect of stimulation of cyanobacteria revealed in laboratory may lead to the changes in biomass of cyanobacteria in the reservoir, observed after the biomanipulation.To test this supposition, a mathematical model describing growth of cyanobacteria in the reservoir was developed. The modelling results and field data on biomass of cyanobacteria in summer closely coincided. Modelling calculations showed that direct influence of planktivorous fish could cause the second summer peak of water blooming by Microcystis. On the contrary, removal of crucian carp from the reservoir will not affect the level of water blooming caused by cyanobacteria Anabaena, as this species’ growth is not stimulated by fish.