Structurally dynamic models of lakes

Abstract

Lakes as all other ecosystems are adaptive, have self-organization, and change the species compositions in accordance with the variable forcing functions. Therefore, models that can capture this dynamics are needed, which means that the properties (represented in models by the parameter) of the biological components of the model are continuously changed. This paper presents what is denoted as structural dynamic models (SDMs) that can capture this dynamics of changing the ecosystem structure. A SDM uses a goal function to determine the changes of the parameters. Eco-exergy is used as goal function, 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. In 23 case studies, it has been possible to use SDM to describe the structural changes with an acceptable standard deviation. Of these cases, 12 were lake models and an attempt is made in this paper to summarize the experience gained by the use of SDMs on lakes. The three most characteristic case studies are presented in more detail and conclusions on the applicability of SDM on lakes are summarized.

Where the Ecological Gaps Remain, a Modelers' Perspective

“…Most disciplines begin with simplifying assumptions as a foundation to build from and ecology has been no exception-note the simplicity of the Lotka-Volterra assumptions for predators and prey. Indeed, the vast majority of extant ecological and ecosystem models still assume fixed parameterisations and even for those that don't (e.g., Jørgensen, 2012) they most often assume fixed functional relationships and formulations. This means, as touched on above, that more remains to be done in terms of representing appropriate levels of variability and dynamic change.…”

Disturbance of Sustainability of the Reservoir Ecosystem: A Model Approach for Assessing and Forecasting the Long-term Process of Eutrophication

“…An efficiency of the method (as the actual progress in the explanation of ecosystem processes) determines the right of existence of the SDM. The use of the SDM had been possible in more than 23 studies at the time of publication of the review [21]. The results of the next section were obtained through the use of the SDM in the study of long-term trends in the ecosystem state for the Novosibirsk reservoir.…”

“…A step forward in this direction is the approach of non-equilibrium thermodynamics, which allows to present a structural change as the passage through the chain of conditionally stable states of the aquatic ecosystem. Structural-Dynamic Modeling (SDM) [21] serves as a basis for the study of qualitative changes in the state and assessment of future development stages of aquatic ecosystems.…”