One important aspect of environmental quality is the functioning of ecosystems. It concerns the biogeochemical cycles, such as the carbon cycle and the nitrogen cycle, and biological purification of ecosystems. These functions, regulation functions or life support functions (LSF), are largely performed by organisms: plants, animals and bacteria. From this point of view biodiversity, the occurrence of organisms in a sufficient abundance and diversity that LSF can be performed on a sufficient level, is a point of interest of environmental policy. To substantiate the environmental policy in this field it was assigned to investigate the possibilities to develop an indicator system for several LSF, to quantify the function in relation to the biodiversity.
In this report we describe the results of a survey of the possibilities to develop an indicator for the self-cleaning capacity of surface water, based on a description of the processes such as the carbon cycle and the degradation of organic micropollutants such as polycyclic aromatic hydrocarbons and chlorinated compounds; the nitrogen cycle with nitrification and denitrification; the sulfur cycle; the phosphorous cycle; the immobilization of heavy metals and the physical transport of pollutants in mowing, water-flow, dredging, and sedimentation.