THECAMOEBIANS AS A TOOL FOR RECONSTRUCTION OF PALEOENVIRONMENTS IN SOME ITALIAN LAKES IN THE FOOTHILLS OF THE SOUTHERN ALPS (ORTA, VARESE AND CANDIA)

A study of thecamoebians was carried out on three sediment cores colle cted in three Northern Italian lakes (Orta, Varese, Candia). The recog nition of distinct morphotypical populations (''morphs'') within three species of thecamoebians in varying paleolimnological settings result ed in a refined understanding of the environmental parameters controll ing their distribution. For example, D. proteiformis morph ''proteifor mis'' is well adapted to environments rich in organic matter and sulph ides whereas D. proteiformis morph ''rapa'' tolerates polluted and aci dified waters (presence of copper sulfates, ammonium sulfates, high co ntent of ammonium and nitrite nitrogen, and water with pH values betwe en 3.9 and 4.5). Although most questions about the ecology of thecamoe bians are still unresolved, this study strongly suggests that with fur ther research these protozoans can be a valuable tool for paleoenviron mental reconstructions and detection of environmental deterioration.