Project Summary: We propose to construct a practical zooplankton population dynamics model based on novel advances in the biomass spectrum theory (Platt and Dernman 1977; Zhou and Huntley submitted). Testing and application of the theory will use eddy resolving CTD OPC (Optical Plankton Counter: Focal Instruments Inc.) data collected in the California Current region during June July 1993 and September October 1993. The novel advances in the biomass spectrum theory explicitly include population dynamics parameters such as rates of individual growth, birth, and mortality. We first developed a general biomass spectrum theory of size structured zooplankton population dynamics based on Platt and Denman's model (1977), and then demonstrated that this theory can be practically applied to estimate zooplankton population dynamics rates and productivity from observations of the biomass spectrum. In this theory, zooplankton, including all species and stages, are classified by weight. For estimating population dynamics rates from field observations and verifying modeling results, we ftu-ther developed an objective interpolation method which removes the effects of advection ftom observations and calculates statistical properties of the spatiotemporal interpolation. This objective interpolation method will be applied to zooplankton data obtained in the California Current region. The results, together with the biomass spectrum theory and individual population growth models. will be used to estimate rates of population dynamics. These rates and zooplankton spatiotemporal distributions allow us realistically to construct and verify a population model. Then we will develop a numerical model based on the biomass spectrum theory and analyzed population dynamics rates, which takes the phytoplankton and physical fields from observations or modeling, and outputs zooplankton spatiotemporal distribution and productivity. This model provides the trophic link between models of phytoplankton and fish, and can be directly embedded into an existing hydrodynamic ecosystem model for ecosystem study and prediction of secondary production. This approach assertively addresses the central GLOBEC paradigm First, it directly addresses population dynamics at the mesoscale. Second, it couples modeling with observations derived from new sampling technology (OPQ. Third, this research involves a conscious effort to provide a model that can assimilate field data and therefore can be used to both guide and interpret GLOBEC observations in Northeast North Pacific Ocean.
