Realization of new production in coastal upwelling areas: A means to compare relative performance

A theoretical basis for analyzing new production of upwelling centers under various conditions and for comparing the relative performance of different upwelling centers has been developed using the concept of shift-up or acceleration of NO3− uptake. NO3− concentration at the beginning of an upwelling cycle determines the rate of acceleration, the maximal specific NO3− uptake rate, and the maximal new production rate achieved. The relationship between initial NO, concentration and new production rate is nonlinear and a doubling of initial NO3− concentration results in a threefold increase in new production. The tendency for new biomass to increase during an upwelling cycle varies widely between different upwelling regions and, by comparing theoretical predictions with data, the performance of an upwelling system can be judged against optimal expectations and the realization of potential new production by the system estimated. Among upwelling centers at Cap Blanc (northwest Africa), 15°S (off the coast of Peru), and Point Conception (California), the least of this potential is realized at Point Conception.