Structurally Dynamic Models

If we follow the modelling procedure proposed in Fig. 2.2, we will attain a model that describes the processes in the focal ecosystem, but the parameters will represent the properties of the state variables as they are in the ecosystem during the examination period. They are not necessarily valid for another period, because we know that an ecosystem can regulate, modify and change them if needed as a response to the change in the prevailing conditions determined by the forcing functions and the...

Ecotoxicological Case Study II Contamination of Agricultural Products by Cadmium and Lead

Agricultural products are contaminated with lead and cadmium originating from air pollution, the application of sludge from municipal waste water plants as a soil conditioner, and from the use of fertilizers. The uptake of heavy metals from municipal sludge by plants has previously been modelled (see J0rgensen, 1975, 1976b). This model can briefly be described as follows. Depending on the soil composition it is possible to find a distribution coefficient for various heavy metal ions, i.e., the...