A new method for measuring microbial biodiversity and its change through time was developed. It is known for some toxonomical groups that a given species assemblage within a complex community can be correlated with environmental quality and resistance of the community to environmental change. As an example the diatom species composition inferred total phosphorus load of a lake may be mentioned. In this example a given diatom species assemblage, which is only a part of the complex lake community, indicates within a certain range the level of total phosphorus load and the susceptibility of the lake towards changes of this load. Undoubtedly, the diagnosis and monitoring of environmental quality in general may be improved considerably if the applied methodology includes the whole microbial biodiversity. But how can we measure microbial biodiversity? A real diagnostic procedure has been missing so far. Our work, based on analyses of various ecological, biological and biochemical properties (including species counts, complex lipids, fatty acids, pigments and others) of sediment samples of 24 European lakes, makes a significant contribution to a complete picture of the interdependency of total biodiversity and lake quality changes.
New analytical procedures were designed and authentic reference samples of biomarkers are now available for standardised measurements by classical biological and gas chromatography (GB) or gas chromatography mass spectrometry (GS/MS) methodologies. The resulting discipline, we call it ecochemometry, allows tentative answers to striking ecological problems, not only for lakes but also for other aquatic systems, sediments and soils. Such knowledge can be used by authorities who are charged with setting and monitoring environmental quality standards as well as by scientists working in environmental research who like to integrate microbial biodiversity in their concepts.