Chapter 2 - Structurally Dynamic Models of Lakes

Lakes as all other ecosystems are adaptive, have self-organization, and change the species compositions in accordance with the variable forcing functions. We need therefore models that are able to capture this dynamic, which means that the properties (represented in models by the parameter) of the biological components of the model are continuously changed. This paper presents structurally dynamic models (SDMs), which are able to capture this dynamic of changing the ecosystem structure. An SDM uses a goal function to determine the changes of the parameters. As goal function is used eco-exergy which is the work capacity (work energy) of the ecosystem. The use of this goal function can be considered a translation of Darwin’s theory to thermodynamics. SDM has been used in 23 case studies to describe the structural changes with an acceptable standard deviation. Twelve of these cases were lake models, and this paper attempts to summarize the experience gained by using SDMs on lakes. The three most characteristic case studies are presented in more detailand conclusions on the applicability of SDM on lakes are summarized.