Most of the Alpine lakes lie in valleys that were formed during the uplift of the mountai....

Most of the Alpine lakes lie in valleys that were formed during the uplift of the mountain chain of the Alps. Parts of the northern lakes (Lakes , Luzern, , , , Attersee) are situated in the foothill zone of the Alps or even some distance beyond. Scientific study of Alpine lakes started in Switzerland with F.A. , who studied the stationary oscillations of the water level (seiches) caused by the wind and also made classic observations on the interrelationship between physical and biological processes in lakes. In the lakes of the Eastern Alps the phenomenon of the (zone of rapid decrease of lake temperature below the warm surface stratum in summer) was first studied in the Wrther See (1891). In the same lake, in 1931, it was discovered that there was an absence of total water circulation during the winter in lakes with wind-sheltered sites. The increasing pollution of Lake Zrich brought attention to chemical and biological changes, and, by the late 20th century, a number of i! nstitutes were studying the pollution of the Alpine lakes. The water composition of the Alpine lakes is quite uniform.