This is an experimental study of the interaction of nutrient flux and food web controls in regulating the productivity of lakes. Four lakes will be manipulated in a 2 X 2 design that tests the capacity of alternative food web structures in response to increased nutrient loading. The theoretical framework for this program is focused on stability and compensatory capacity of ecosystem processes. It is based on scale-dependent perspectives that range from diel dynamics to paleolimnological calibration and from single species to entire communities. Models developed by the program will range from population dynamics of individual cohorts to integrated indicators of trophic level responses. Results of this study will provide both conceptual and tactical advances in furthering the use of food web management techniques as a means for improving water quality. This is an excellent research team that has been involved previously in trophic cascade research. The facilities available for this research are outstanding.