Adult body size in marine zooplankton varies with season and latitude. Larger body sizes are associated with colder seasons and higher latitudes. Since warmer environments and seasons also tend to process less prey, the interaction of food and temperature may have important influences on body size. Because body size affects all aspects of an individual's ecology, explanations of body size must consider it a possible life history adaptation to a changing environments in ways that are not yet well understood. This project will begin the development of a set of size-classified population models, and use them to predict optimal body size patterns on the basis of maximization of individual fitness. The models will incorporate size-specific growth, mortality, and fecundity rates and the responses of those rates to temperature and food. Models will be parameterized based on information in the literature. The resulting models will be simulated in the context of seasonally varying temperature and food signals, to see how the optimal life history responses affect population dynamics.
