Abstract
The effects of aluminium sulphate (6 ppm Al3+) on freshwater plankton (phyto‐and zoo‐) and the water quality have been studied using the “enclosure”; method in the shallow eutrophic Lake Comabbio (Lombardy, Northern Italy). Soon after Al3+addition dramatic modifications of the physical, chemical and biological characteristics, were detected. Several days after the beginning of the experiment the “microecosystems”; began to recover with the exception of PO4 concentration and Zooplankton structure.