Dynamics of hydromechanical indicators, diversity and quantitative development of phytoplankton in small lakes as a feedback to biological manipulations in progress

Russian. Рассмотрены некоторые особенности динамики видового состава и количественного развития фитопланктона двух малых озер при проведении на них биоманипуляций с использованием хищных рыб. Дана оценка качественной значимости динамики и высказываются возможные предположения по связи выявленных изменений c гидрохимическим режимом и развитием планктонных беспозвоночных.

English. There were reviewed some peculiarities in dynamics of species composition and quantitative development of phytoplankton in two small lakes at biological manipulation with application of predatory fish in progress. The research was realized in the conditions of the Republic of Belarus. There was estimated the qualitative importance of dynamics and there were set force the possible assumptions on the interconnection between the changes discovered with hydrochemical condition and development of backboneless plankton. Comparison of experimental water quality of lakes confirmed the trophic type (status) of water bodies, and their differences in 2011 and subsequent years could be explained by seasonal factors and the result of ongoing manipulation. Dynamics of the major hydro-chemical indicators of water bodies (water clarity, the content of basic nutrients) for a three-year period of observations fit into the overall presentation of the impact of biomanipulation on the principle of ‘top-dawn’. In carrying out the ‘top-dawn’ biomanipulation in phytoplankton communities of lakes there were marked structural changes consisting in a change of species diversity, including availability protococcal forms, change of the relative importance of the individual departments and taxa of algae, decreasing the quantitative (absolute and relative) values of taxon-indicators of polluted water.