Use of algae for monitoring rivers in Hungary

Algological monitoring in Hungary started in the 1960s – 1970s and its technical guidelines were elaborated by 1984. Streams and rivers are monitored at 155 sampling stations by a sampling frequency of 4-52/year. Based on trophic scales (chlorophyll-a, algal numbers) trophic states are established. A saprobic classification is made according to the list of saprobic indicators species. The paper summarizes the opinions of many Hungarian algologists involved in monitoring about the advantages and pitfalls of the existing monitoring system. Since the authors’ conviction is that computer problems and methods for handling large databases and the exploration of their information content will become one of the major difficulties in connection with algological monitoring, a pilot study was made on an already existing databank. The outcome of this study was that, however much the original single data-sets were different, large databanks can be useful in searching for variables that can be used for monitoring water quality. simple variables (e. g. the ratio of diatoms to non-diatoms) and multivariate methods can be applied with a godd measure of success