where Q = biomass of organisms consumed; M= biomass of dead organisms during the whole observation period. Let us consider 3 cases: (A) If phytoplankton grazing is non-uniform during the whole day according to Eq. (2), then the corresponding value Q obtained with the help of q from (5) is included in the calculation of the production(16) if Bt=B0 then, from (16) To calculate q we find the amplitude a from(4'')If we calculate Q from the Eq. (10), the value for production or, substituting A from(4") for the case when Bt=B0 we get