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IMPORTANCE OF TEMPERATURE IN MODELLING PCB BIOACCUMULATION IN THE LAKE MICHIGAN FOOD WEB
Zhang, X. AND R G. Kreis. IMPORTANCE OF TEMPERATURE IN MODELLING PCB BIOACCUMULATION IN THE LAKE MICHIGAN FOOD WEB. Presented at International Association for Great Lakes Research International Conference, Green Bay, WI, June 10-14, 2001.
In most food web models, the exposure temperature of a food web is typically defined using a single spatial compartment. This essentially assumes that the predator and prey are exposed to the same temperature. However, in a large water body such as Lake Michigan, due to the spatial gradient of temperature, the immediate exposure temperature can be quite different among organisms of a food web. To accommodate the differential exposure temperature of organisms in a food web, organism-specific descriptions for exposure temperatures would be required in modeling practice. This work investigates the necessity of introducing a multi-compartment approach to define the exposure temperatures in food web model frameworks. It analyzes the influence of temperature to key model parameters in a bioenergetics-based bioaccumulation model, and the propagation of the temperature dependencies along model calculations of the bioaccumulation rate of different PCBs in lake trout. It shows that, in most cases, inadequate definition of the exposure temperature can significantly alter the model estimates of the PCB fluxes between fish and their environment. Time dependent model simulations of PCB bioaccumulation were further conducted using an individualized and an indiscriminate approach for exposure temperature. The results demonstrate the importance of refining the model definition for exposure temperature.