Estimation of Primary Production in the Water of the Coastal Zone of Lake Baikal Based on Daily Variations in CO 2 Concentration in Different Seasons of 2005–2021

The gross and net primary production is estimated for the most characteristic seasonal life cycles of Baikal plankton based on long-term measurement series of carbon dioxide concentrations in the near-water atmosphere and surface and bottom water and “water–air” carbon dioxide fluxes. The calculations are carried out according to the scheme similar to the diel technique. With regard to the conditions of the coastal zone, the methodological issues are analyzed, neglect of which can lead to a significant uncertainty in these characteristics. We show that it is impossible to correctly estimate the net primary production only from CO 2 concentration measurements in this technique. For periods of open water, the net primary production is calculated from the daily average CO 2 flux. The estimates of the productivity for individual series of measurements in different periods quite adequately show the main features and are consistent with long-term observations.