Initial plant tests (calibration phase)

The main objectives of the test phase (calibration phase) were to ensure that the plant’s basic functions were working properly, as well as to define key parameters. The experiences are documented in a technical-scientific manual, which will help researchers to become familiar with the opportunities offered by the FSA and provide important information for the planning of projects in the future. During the test phase, further objectives were among other things to compare the research results obtained from the mesocosms with different types of natural aquatic systems, to verify the stability and the dynamics of the biocoenosis in the mesocosms as well as the biological synchronicity of identical systems in uncontaminated state.

The comparison of selected natural flowing and stagnant water bodies (reference ecosystems) with the stream and pond mesocosms showed that the FSA provides the overall conditions for modelling various types of water bodies (Fig.1). However, it also became apparent that in the case of streams operated in circulation mode in the summer, only simulation of summer warm stream systems is possible, since the exposed streams warm up quickly and no cooling (ground) water is added to them. Summer cold rivers can only be simulated in the indoor streams during the cold season.

In studies on the synchronicity of the systems (parallel development of all systems with regard to the biological dynamics and their impact on functional parameters like O 2 , nutrient budget etc.), it was asserted that the design and construction of mesocosm systems must pay particular attention to the placement of soft sediment and to identical direct and indirect lighting.

If this is not considered, the systems can diverge rapidly and no definite statements on the effects of pollution can then be deduced from the results. Sediment management management, in particular of the flowing water systems, will therefore play an important role in management of the FSA in future.