In a recent publication (Jamart el al., Deep-Sea Research, 24, 753–773, 1977) we describe a numerical two-dimensional (time and depth) model of phytoplankton growth and nutrient distribution in the Pacific Ocean off the northwestern U.S. coast. The numerical model consists of coupled integro-partial differential equations expressing conservation of chlorophyll α, nitrate, and ammonium. The relevant physical and biological processes are represented by conventional functions and parameters. The system is “closed” by specification of grazing pressure and light intensity. A long-term simulation ova spring and summer months (for convenience, called the “standard run”) represents well the main features of observed chemical data and biological variables, including the formation and deepening of a subsurface chlorophyll maximum. In this paper, a sensitivity analysis of the system is carried out by comparing the “standard run” with the results of twenty numerical experiments, in each of which a single function or parameter in the model is modified. The formation of the subsurface chlorophyll maximum is simulated, more or less realistically, in all experiments. Moreover, the results suggest that the chlorophyll distribution adjusts in time and depth so as to optimize the transfer of carbon to secondary producers. The level of the carbon output is determined mainly by the resources available to the primary producers.
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Jamart et al. (1979) studied this question.