Seasonal primary production cycle in Lake Onega

A long-term average curve of seasonal changes in the primary production of phytoplankton in the pelagial zone of Lake Onega has been plotted on the basis of experimental data approximated by a prescribed function. Long-term average values of primary production for each day of the growing season and its integrated and daily average values for different periods of the season have been calculated. Interannual variation of the seasonal process of primary production has been analyzed, and its quantitative estimations are given. The influence of basic environmental factors on the seasonal dynamics of primary production is discussed.