Temperature and water fluctuations southern Caspian sea 

A special temperature fluctuation exists in waters of Southern Caspian Sea Depth survey of upto 100 m indicates that there are two thermal phenomena annually, One thermal phenomenon occurs in summer and autumn and the other one in winter and spring. The least disolved oxygen concentration at various depth was recorded in depth of 100 m and was 7 mg/l, This is an indication of good mixing of lake strata because of two cold cycles in winter and spring...... Reference