where phytoplankton standing stock at the beginning of grazing to Bt =standing stock at the end of grazing Thus the Eq. (3) allows change in phytoplankton standing stock if reproduction, grazing and mortality of the algae are taken into account. Fig. 1 consists of 3 curves determining(1) increase in phytoplankton standing stock(exponential since eliminating is lacking); (2) changes in grazing rate; (3) changes in phytoplankton standing stock as a result of a momentary action of both reproduction and elimination. From(3), knowing the coefficients k and ku, initial Bo, and finite Bt phytoplankton standing stock, one can determine the amplitude A for curve(2)